Tag Archives: battery

Scientist accidentally invents a rechargeable battery that could virtually last forever

Mya Le Thai holds her invention. Credit: Steve Zylius, UC Irvine.

From the pacemaker to stainless steel and Velcro, some of the world’s most useful inventions were made by accident. A nanowire battery might someday make this impressive list, too. Made by accident at the University of California at Irvine while a Ph.D. student was toying with nanowires in the lab, the rechargeable battery could last for decades.

The lithium-ion battery inside your laptop or smartphone is only designed to last 300-500 charge-discharge cycles, or roughly 2-3 years. It all depends on how you use it. For instance, as a general rule of thumb, 5 to 10 shallow discharge cycles are equal to one full discharge cycle. Partial-discharge cycles are actually recommended to boost battery life, while you should avoid as much as possible completely discharging the battery.

Suffice to say, no matter how careful you are, that Li-ion battery will eventually stop charging. Most will end up in landfills, wasting a lot of resources that have gone into the mining of lithium and the manufacturing of the battery, as well as resulting in environmental pollution.

This is why scientists are always on the lookout for batteries that can store a decent amount of charge and can withstand a much higher number of cycles while avoiding toxic components or unsustainable manufacturing.

A stroke of genius

One such battery may be a promising nanowire alternative. Funny enough, Mya Le Thai, who in 2016 used to be a P.hD candidate at the University of California at Irvine, made it completely by accident.

Nanowires are tiny conductive wires less than 100 nanometers in diameter with good properties as batteries. But their tiny size makes them extremely fragile, which causes them to fray and crack easily after a number of charging cycles.

One faithful day, Le Thai switched the liquid electrolyte that bathed the nanowire assembly with a gel capacitor. During subsequent tests, she later found, much to her surprise, that the nanowire battery had been cycling through more than 10,000 charges and was still going. A few days later, it was still cycling for more than 30,000 instances. It kept on going for a month.

The gel, which is thick like peanut butter, slowly seeps into the pores of the nanowires made of manganese oxide. This makes them softer, which greatly reduces their fragility.

“If you could get 100,000 cycles out of a lithium-ion battery it might mean you never need to buy two of them,” said Reginald Penner, chair of the university’s chemistry department. “We’re talking about a lifetime of 20 years, maybe even longer than that.”

Electron microscope image of the nanowire whose pores are filled with the gel. Credit: Penner Lab, UCI.

Le Thai and others in Penner’s team are still experimenting with gel-wrapped nanowire batteries. Meanwhile, the market is betting big on them due to their fast charging and much longer lifetime, compared to lithium-ion. The nanowire battery market is set to grow from $53 million in 2021 to $243 million by 2026, by one estimate. Most of this growth will be fueled by the high adoption rate of electric vehicles in the coming 4-5 years.

Polymer-coated red bricks could turn your entire home into a battery

Artist impression showing core-shell architecture of a nanofibrillar PEDOT-coated brick electrode. Credit: D’Arcy laboratory, Department of Chemistry, Washington University in St. Louis.

Red bricks have been the building material of choice for centuries. They’re cheap, great thermal insulators, and add a quaint look to neighborhoods. But that’s not all — imagine plugging your mobile device straight into your brick house to charge it. Researchers at the University of St. Louis showed that such a scenario is possible, converting red bricks — and by extension your entire house — into batteries for energy storage.

Julio D’Arcy, an assistant professor of chemistry at Washington University in St. Louis, previously published a number of papers showing plastics can be used to store energy when they can conduct electricity.

“They are a lot of fun – we also have record breaking devices that can be cycled 350,000 times using our plastics and which continue to put out energy. Using a brick was a natural evolution for us because its pigment is basically a form of iron corrosion which we have used in the past and which we knew we could tailor to our advantage to produce an even better electrically conducting plastic,” D’Arcy told ZME Science.

To essentially turn plastics into supercapacitors, D’Arcy and colleagues employed iron corrosion in chemical syntheses. In their new study, the researchers worked somewhat in reverse. Instead of adding iron corrosion to plastic, they put a coat of polymers onto red bricks, whose pigments contain iron oxides.

The conductive plastic coating developed by the researchers, known as PEDOT, is composed of nanofibers that percolate through the inner porous networks of the bricks, serving as ion sponges that can both store and conduct electricity. Alas, the process also turns the bricks blue instead of red.

“We do this by flowing gases that react with the red pigment. A brick, when coated by our polymers, behaves like a semiconductor because the polymer coating is responsible for this behavior. We have in essence converted an inert and stable construction material into a semiconductor. When you apply a potential to our polymer, it experiences this potential and retains it (this can be achieved using a solar cell that is connected to a polymer-coated wall). Connecting two polymer bricks together allows us to develop a positive potential on one brick and a negative on the other thereby creating a two-electrode system that can store electricity when these bricks are sandwiched together, this is similar to stacking bricks on a wall except the stacking here enables the flow of electricity between bricks,” D’Arcy explained.

But although this sounds straightforward, the researchers had to overcome a number of challenges. To penetrate the brick to its pores and initiate the chemical reaction that applies the polymer, a specific flow rate for the gases is required. The researchers carried out no fewer than 1,000 syntheses before finding a process that works best to convert bricks into batteries.

This all works with both regular and recycled bricks. In fact, the researchers used off the shelf bricks bought at Home Depot in Missouri, with each brick costing no more than 65 cents.

Does this all mean you could turn your brick walls into a home-sized battery? Indeed, that’s something that might be possible in the future. Solar panels on the roof could generate energy during the day, while the bricks would power the home during the night. According to D’Arcy, an averaged-sized American house could store up to 300Wh of energy.

“Our bricks have an energy density that is 2 orders of magnitude lower than a lithium-ion battery. However, our bricks do not catch on fire because they use water in the device and also our device can be recharged 10,000 times!” D’Arcy explained.

There are quite a few practical challenges that need to be overcome before polymer-coated bricks become a thing. For now, the researchers are focused on improving the energy density.

“We are actively working on increasing the amount of energy that can be stored in our bricks – when we increase the energy density by one order of magnitude, we would like to power mobile devices. We believe that we are close to this goal because current findings in our lab show promising results,” D’Arcy concluded.

The findings were described in the journal Nature Communications.

The UK may soon get its first cryogenic energy battery

Energy storage company Highview Power has announced its intention to build a cryogenic energy storage facility in the north of England, a first for the U.K.

Image credits Highview Power.

A decommissioned power plant will be converted to house the cryobattery, according to Highview Power. After completion, the installation will have a 50 MW/250 MWh capacity (roughly as much energy as 25,000 households use in a day) that it will store without using water, toxic materials, and with no emissions. The energy to be stored here will be sourced from renewable sources, the company adds.

So how does it work?

I have bad news: there will be very little cryogenics going on at the cryobattery. In fact, no freezing or unfreezing of people is so far planned. Bummer.

However, what the battery will do is use electricity sourced from renewable sources (such as wind or solar) to compress huge volumes of air and store them in tanks. It’s a ‘cryo’ battery because there is a point, if you compress air enough, where it turns into a (very very cold) liquid; that’s the form it will be stored in. When energy is needed in the grid, the compressed air will be allowed to warm up, decompress, and escape the tanks — all while powering a turbine.

Highview Power said that they pitched the concept to the U.K. government, which is looking for ways to meaningfully reduce the country’s carbon emissions. They further note that the compressed air approach is much cleaner than conventional batteries. The cryobattery doesn’t involve the use of any toxic chemicals, it doesn’t need rare or advanced materials to be built (which means less environmental damage since you don’t need to produce and extract them), and doesn’t produce any emissions. Additionally, it can hold energy for up to several weeks at a time, which is longer than in traditional batteries.

The system is expected to boost local grid stability and reliability by storing renewable energy when bountiful, and releasing it when needed. Highview noted that the process is well-established already, having been used for natural gas storage. The company plans to build more cryogenic batteries across the U.K. in the future, and CEO Javier Cavarda said they’re also in talks with officials from Spain, South Africa, and several Middle Eastern countries.

Nobel Prize in Chemistry awarded to trio that created today’s lithium-ion batteries

The Royal Swedish Academy of Sciences has decided to jointly award the Nobel Prize in Chemistry 2019 to John B. Goodenough, M. Stanley Whittingham (USA), and Akira Yoshino (Japan) “for the development of lithium-ion batteries“.

Image credits Nobelprize.org

This year’s Nobel Prize for Chemistry recognizes the importance of the lithium-ion battery in today’s world. Such batteries are lightweight, rechargeable, and powerful enough for a wide range of applications. From mobile phones to laptops and electronic cars, the lithium-ion battery keeps our world in motion. They’re also one of the cornerstones of fossil-fuel-free economies, as they’re able to store energy from renewable sources for long stretches at a time (they can withstand many recharge-discharge cycles).

No breaking down

The advantage of lithium-ion batteries is that they are not based upon chemical reactions that break down the electrodes, but upon lithium ions flowing back and forth between the anode and cathode.

Lithium-ion batteries have revolutionized our lives since they first entered the market in 1991. They have laid the foundation of a wireless, fossil-fuel-free society, and are of the greatest benefit to humankind.

The lithium-ion battery can trace its origin back to the oil crisis of the 1970s, the commission explained. Against this backdrop, a researcher named Stanley Whittingham was working to develop energy technologies that would not depend on the use of fossil fuels. His work with superconductors paved the way for the development of an innovative cathode for lithium batteries. This cathode was built from titanium disulfide which, at a molecular level, has spaces that can fit – intercalate – lithium ions. Today, the concept is known as electrode intercalation.

The anode in a Li-Ion battery (the positively-charged part) is made of metallic lithium, which is a strong electron donor. Coupled with the new cathode, such a battery could produce just over two volts of power, which is a lot. However, this battery was also very unstable, as metallic lithium is highly reactive — and it posed a real risk of explosion.

John Goodenough predicted that replacing the titanium disulfide in the cathode with a metal oxide would boost the battery’s capacity (measured in volts) to even greater heights — a hypothesis he proved in 1980 using cobalt oxide. His battery produced up to four volts, paving the way towards much more powerful batteries.

Akira Yoshino built on Goodenough’s findings to produce the first commercially viable lithium-ion battery in 1985. He replaced the lithium in its anode with petroleum coke, a carbon-based material that could intercalate lithium ions. The resulting battery was a lightweight, robust battery that could withstand hundreds of cycles without any drop in performance. The secret to their success is that they don’t rely on chemical reactions to generate power (these break down electrodes over time) but on the physical flow of lithium ions between the anode and cathode.

Lithium-ion batteries have revolutionized our lives since they became commercially-available in 1991. Whenever you poke at your phone, hit the power button on your laptop, or start your Tesla, know that the work of these three laureates made it possible.

The million-mile battery promised by Tesla is here

Elon Musk promised a battery that could take an e-vehicle a million miles and last for years at a time. Jeff Dahn, one of the pioneers of the modern lithium-ion batteries, has now delivered on that promise.

Image credits Paul Brennan.

In a new paper, Dahn announced that the company will soon be in possession of a battery that would make its robot taxis and long-haul electric trucks viable. Dahn is a Professor in the Department of Physics & Atmospheric Science and the Department of Chemistry at Dalhousie University, as well as a research partner of Tesla.

Charge for days

“Cells of this type should be able to power an electric vehicle for over one million miles and last at least two decades in grid energy storage” Dahn says.

Dahn’s research group is recognized as one of the most renowned and prestigious worldwide in the field of electrochemistry. Their new paper details the new power cell they created and a benchmark of its capabilities for further research.

The power cell is constructed using a nickel-rich NCM (nickel-cobalt-manganese) alloy for its cathode. The team explains that the alloy they used, known as NCM 523 (50% Nickel, 20% Cobalt, 30% Manganese), is stable and an excellent reference and starting point for further developments. Other elements that the team tested include graphite anodes, and different mixes of solvents, additives, and salt for the electrolyte solutions

All in all, the cells have a specific capacity (the ratio of energy storage ability to weight) 20% higher than that of the cathodes used in Li-ion batteries that power today’s mobile electronic devices. What’s more, the findings can be turned into useable batteries right away.

“However, since the goal of the study was to provide a reliable benchmark and reference for Li-ion battery technology, the specific energy density of the batteries described is not the highest compared to what can be really reached by advanced Li-ion batteries,” says Doron Aurbach the batteries and energy storage technical editor for the journal that published the study.

“Based on the study, Li-ion batteries will soon be developed that make driving over 500 kilometers (over 300 miles) from charge to charge possible.”

The paper “A Wide Range of Testing Results on an Excellent Lithium-Ion Cell Chemistry to be used as Benchmarks for New Battery Technologies” has been published in the Journal of The Electrochemical Society.

Tesla’s new batteries could last for one million miles or two decades of energy storage

Tesla’s electric vehicles are designed to last a very long time. That’s because Elon Musk wants to, at some point, launch a huge fleet of autonomous taxis, and the economics of this venture only make sense if each car can operate for hundreds of thousands of miles, preferably around a million.

While the other parts are already up to the task, the lithium-ion batteries are rated for only 300,000 miles (480,000 km).

However, Tesla researchers say that they’ve now completed tests showing the new battery pack they’re working on could last for up to a million miles (1.6 million km) or 20 years of operation if used for energy storage in a home or by a utility. That’s two to three times longer than current commercially available battery packs offered by Tesla.

The new battery is based on a next-generation single-crystal nickel-manganese-cobalt (NMC) cathode, as well as a new electrolyte.

Tesla researchers led by Jeff Dahn tested the new technology for the last three years, including “long-term charge-discharge cycling at 20, 40 and 55°C, long-term storage at 20, 40 and 55°C, and high precision coulometry at 40°C,” according to their new study published in the Journal of The Electrochemical Society.

Even at 40°C, which is pretty extreme, the cells lasted for about 4,000 charge-discharge cycles. If an active cooling system is added, which is already present in Tesla’s battery pack, then the cells can last up to 6,000 cycles or roughly 1 million miles.

“This situation may change with the proposed introduction of “robo taxis”, long haul electric trucks and vehicle-to-grid applications. In the former, vehicles will be driving all day, much like a conventional taxi and undergoing nearly 100% DOD cycling. Long haul trucks will almost certainly run in near 100% DOD situations,” the researchers wrote, describing the enormous potential their improved battery life could have on transportation.

Tesla not only builds its own cars but also its own batteries via Gigafactories. Having top-down control over the supply chain means that Tesla is at an economic advantage over the competition that could enable it to control a fleet of thousands of autonomous Tesla taxis around the world.

Imagine a fleet of around the clock Ubers that only stops to charge, making trips and deliveries. Tesla owners would also be able to send their cars off to make money for them when they’re not using them, when they’re sleeping or away on vacation, for example. I don’t know about you, but this all sounds like the future — I like it!

Credit: Pixabay.

Breakthrough could double energy density of lithium-ion batteries

Credit: Pixabay.

Credit: Pixabay.

Lithium-ion batteries power everything from cell phones to electric vehicles. Naturally, consumers want devices that last for longer and longer, but increasing energy density has proven challenging due to engineering roadblocks. Every once in a while though, there are breakthroughs — like the recent research at Penn State that might not only double the energy density of lithium-ion batteries but also make them safer and extend their lifespan.

Cleaner electrodes

Li-ion batteries are enabled by a protecting layer on the negative electrode, which self-forms as a result of electrolyte decomposition, a process called solid electrolyte interphase (SEI). This so-called passivation layer is important because it offers just enough electronic resistance to limit electrolyte decomposition. However, through repeated use, this layer’s growth leads to capacity fade and increased cell resistance.

Over time, needle-like dendrites grow on the lithium electrode, inhibiting performance and safety.

“This is why lithium metal batteries don’t last longer—the interphase grows and it’s not stable,” Donghai Wang, Professor of Mechanical and Chemical Engineering at Penn State, said in a statement. “In this project, we used a polymer composite to create a much better SEI.”

A reactive polymer composite, picturing the electrochemical interface between lithium metal anode and electrolyte is stabilized by the use of a reactive polymer composite. Credit: DONGHAI WANG.

A reactive polymer composite, picturing the electrochemical interface between lithium metal anode and electrolyte is stabilized by the use of a reactive polymer composite. Credit: DONGHAI WANG.

To bypass this roadblock, the engineers devised a new SEI — a reactive polymer composite made up of polymeric lithium salt, lithium fluoride nanoparticles, and graphene oxide sheets. Many thin layers of this polymer react to make a claw-like bond to the lithium metal surface so that it doesn’t react with the electrolyte molecules. This was achieved by controlling the surface of the lithium at the level of individual atoms and molecules.

The reactive polymer also decreases the weight and manufacturing cost, further enhancing the future of lithium metal batteries.

“With a more stable SEI, it’s possible to double the energy density of current batteries, while making them last longer and be safer,” Wang said.

The research was published in the journal Nature Materials.

Conventional CAES.

The North Sea could become the UK’s largest battery — one that lasts for the whole winter

The UK’s coast may be useful as a huge battery of renewable energy, new research suggests.

Beach.

A beach on the North Sea, Denmark.
Image credits Willfried Wende.

Rocks off the UK’s coast could be used as long-term storage for renewable energy, according to earth scientists from the Universities of Edinburgh and Strathclyde. The energy storage method involves pumping compressed air into local, porous sandstone formations, which can later be released to generate large quantities of electricity.

Air pockets

Using such a technique on a large scale could store enough compressed air to cover the UK’s winter energy needs — when demand is highest — the authors explain.

“This method could make it possible to store renewable energy produced in the summer for those chilly winter nights,” says lead author Dr. Julien Mouli-Castillo of the University of Edinburgh’s School of GeoSciences.

“It can provide a viable, though expensive, option to ensure the UK’s renewable electricity supply is resilient between seasons. More research could help to refine the process and bring costs down.”

The main drawback of renewable energy such as wind or solar is that it isn’t very reliable. Sometimes they produce a lot of energy, sometimes they don’t produce any. This variation in output is highly dependent on weather conditions, which tend to vary by season. That’s why renewable energy is best paired with storage systems such as batteries, for example, so that any surplus can be stored and released as needed.

Engineers and geoscientists from the Universities of Edinburgh and Strathclyde used mathematical models to assess the potential of compressed air energy storage (CAES) processes in the UK. Such systems are is already in use in certain sites in Germany and the US. CAES involves using an electric motor to compress air and pump it at high pressure into porous geological layers when energy is plentiful. When supply can’t keep up with demand, this air is released to power turbines that generate electricity and feed it into the grid.

In essence, CAES-type systems act as a compressed-air electrical battery.

Conventional CAES.

A conventional CAES-type installation. The one proposed in this paper does away with the ‘fuel’ and ‘combustion’ bits, essentially turning it into a renewable-energy battery.
Image credits Julien Mouli-Castillo et al., (2019), Nature Energy.

The team predicted the UK’s storage capacity by combining the results of their modeling with a database of geological formations in the North Sea. Porous rocks beneath UK waters (in the North Sea) could store about one and a half times (160%) the UK’s typical electricity demand for January and February (77–96 TWh), they found.

Setting up a CAES system for the UK would be quite expensive and laborious, the team notes, since the infrastructure needs to be built from the ground-up — we’d need to drill injection wells and lay down long stretches of undersea cables, for example. But measures can be taken to reduce costs and labor associated with its installment. For example, locating injection wells close to sources of renewable energy, or installing new ones close to areas where drilling is planned.

Such measures would also make the system as a whole more efficient, they add. Roundtrip energy efficiency (the ratio between energy input and energy retrieval in a storage system) predictions based on the UK’s current grid and generation area layout would be around 54–59%, with a potential storage cost in the range US$0.42–4.71 per kWh1.

The paper “Inter-seasonal compressed-air energy storage using saline aquifers” has been published in the journal Nature Energy.

Australia opens first off-the-grid, solar-powered classroom, using Tesla battery

Sustainability is coming to the classroom, as an Australian school inaugurates the first of several off-the-grid modules. The classroom is powered by solar energy, using a Tesla battery for energy storage.

Image credits: ARENA.

After successful trials supported by the Australian Government, the new classroom technology was installed in Brisbane, one of Australia’s largest cities. It features rooftop photovoltaic (PV) panels and a Tesla Powerwall battery for energy storage, ensuring that electricity is provided at all points, and reducing costs in the process.

A key element that allowed this innovation is the battery.

Tesla batteries came in ready to take the world by storm, striving to solve one of the main problems with renewable energy: storage. Renewable energy (solar and wind especially) have a big problem with availability — you can have a lot of energy at some point in the day, when it’s windy/sunny, and long periods with reduced availability. How do you store the energy?

Despite great efforts, progress in the battery domain has been slow, and few (if any) realistic options exist for energy storage at a household level. Tesla promised to change all that with its Powerwall batteries, which are essentially rechargeable lithium-ion batteries intended for home energy storage or similar applications.

An Australian tech start-up called Hivve had the idea to use it for classrooms. They received support from the national government and were able to implement this idea, saving an estimated $3,000 yearly per classroom, as well as $30,000 in upfront costs of connecting a new classroom to the power supply.

Image credits: ARENA.

The result is an off-the-grid classroom with sufficient electricity, and substantial savings (despite an initial investment). It also incorporates solar PV generation, real-time energy metering, CO2 metering, data capture, and communications to the overall function. Hivve also mentions some relevant stats:

  • The energy consumption for 3 regular non-HIVVE classrooms is 11,400 KWh per year (baseline comparison).
  • The energy consumption for 3 classrooms when 1 of the classroom is a HIVVE classroom is 0.
  • When all 3 classrooms are HIVVE classrooms, there is an estimated net energy generation of 22,800 KWh (7,600 KWh per classroom) per year (i.e. export).
  • Therefore, in the instance where 3 HIVVE classrooms are installed, instead of one classroom consuming 3,800 KWh per year, that one classroom will now generate 7,600 KWh per year.

Image credits: ARENA.

Several other classrooms are already being set up in a similar fashion. The classrooms will be monitored and evaluated over a 12 month period, and if everything goes according to plan, off-the-grid classrooms will likely become more and more common. It’s a promising concept.

“The success of the Hivve project could lead to a nation-wide adoption of the modular classrooms, reducing reliance on the grid and even providing a significant amount of electricity back to the NEM.” said Ivor Frischknecht, CEO of the Australian Renewable Energy Agency (ARENA).

Credit: Pexels.

New cathode might triple energy storage of lithium-ion batteries

Credit: Pexels.

Credit: Pexels.

Lithium-ion batteries represent the most widely used energy storage medium for mobile demand, such as smartphones, electric vehicles, and renewable energy. Scientists around the world are actively working on devising new ways to make these batteries last longer. Now, a significant breakthrough might triple the energy density of lithium-ion batteries.

The news was reported by a team of researchers at the University of Maryland (UMD), the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, and the U.S. Army Research Lab. Writing in a new study published in Nature Communications, the researchers described a new cathode material, an engineered form of iron trifluoride (FeF3).

Unlike most cathodes used in commercial energy storage hardware, iron trifluoride is composed of environmentally-friendly and cheap elements. Both iron and fluoride offer inherently higher capacities than traditional cathode materials.

A battery essentially consists of electrochemical cells connected in series or parallel to provide voltage and capacity. Each cell contains a positive (cathode) and negative (anode) electrode, which divided by an electrolytic solution, simply called an electrolyte, with dissociated salt that allows ion transfer between electrodes.

Typically, graphite anodes used in most lithium-ion batteries have a much larger capacity than cathodes. “Cathode materials are always the bottleneck for further improving the energy density of lithium-ion batteries,” said Xiulin Fan, a scientist at UMD and one of the lead authors of the paper.

“The materials normally used in lithium-ion batteries are based on intercalation chemistry,” said Enyuan Hu, a chemist at Brookhaven and one of the lead authors of the paper. “This type of chemical reaction is very efficient; however, it only transfers a single electron, so the cathode capacity is limited. Some compounds like FeF3 are capable of transferring multiple electrons through a more complex reaction mechanism, called a conversion reaction.”

Substituting the cathode material with oxygen and cobalt prevents lithium from breaking chemical bonds and preserves the material's. Credit: Brookhaven National Laboratory

Substituting the cathode material with oxygen and cobalt prevents lithium from breaking chemical bonds and preserves the materials.
Credit: Brookhaven National Laboratory

The FeF3 cathode has the potential to triple the energy density of lithium-ion batteries, according to the researchers. If this potential is ever fully reached, it could accelerate our transition away from fossil fuels to renewable energy. Imagine driving an electric vehicle with three times the range currently available or a home that can store three times as much energy from its solar panels during the night.

Of course, FeF3 cathodes aren’t exactly new to science. However, historically this type of cathode has been plagued by three major complications: poor energy efficiency (hysteresis), a slow reaction rate, and side reactions that can cause poor cycling life.

The researchers overcame these challenges by doping the FeF3 nanorods with cobalt and oxygen atoms through a process called chemical substitution. This tweak allowed the researchers to manipulate the reaction pathway of the cathode, making it more “reversible.”

“When lithium ions are inserted into FeF3, the material is converted to iron and lithium fluoride,” said Sooyeon Hwang, a co-author of the paper and a scientist at Brookhaven’s Center for Functional Nanomaterials (CFN). “However, the reaction is not fully reversible. After substituting with cobalt and oxygen, the main framework of the cathode material is better maintained and the reaction becomes more reversible.”

Using a technique called transmission electron microscopy (TEM), researchers at the Center for Functional Nanomaterials (CFN) fired a powerful beam of electrodes on the new cathode nanorods. The imaging experiment, which had a resolution of 0.1 nanometers, revealed the exact size of the nanoparticles that comprise the cathode structure. This step was important, as it showed the researchers that the cathode had a fast reaction speed when changing between different phases of the charge-discharge process.

Unfortunately, TEM can only be used to peer inside a limited area of the sample. So the researchers turned to the National Synchrotron Light Source II (NSLS-II), where they directed the X-ray Powder Diffraction (XPD) beamline through the cathode material. By analyzing how the light scattered, the scientists could “see” additional information about the material’s structure.

Researchers say that their strategy could be applied to other high-energy conversion materials.

Opportunity.

Opportunity braves the worst sand storm it’s ever faced, might not make it

Shoutout to the Opportunity rover for signaling home amid the worst Martian sandstorm it’s ever faced.

Mars map.

This global map of Mars shows a growing dust storm as of June 6, 2018. The map was produced by the Mars Color Imager (MARCI) camera on NASA’s Mars Reconnaissance Orbiter spacecraft. The blue dot indicates the approximate location of Opportunity.
Image and caption credits NASA/JPL-Caltech/MSSS.

On Sunday morning, NASA received a transmission from the Opportunity rover. Usually, that’s not really out of its character — but the bot is currently braving a massive sandstorm on the Red Planet. The rover hailed home to let ground control know it still has enough juice in its battery to maintain communications, according to NASA. Science operations, however, remain suspended in a bid to conserve energy.

Oppy phone home

The transmission was a welcome break for NASA engineers, as the dust storm has been steadily picking up steam in the past few days. The rover is weathering it out in Perseverance Valley, shrouded in perpetual night. NASA’s Mars Reconnaissance Orbiter first detected the storm on Friday, June 1. The rover team began preparing contingency plans soon afterward.

It’s not the first such storm Opportunity had to face — it braved another in 2007. This event, however, is much worse than the last one. The storm’s atmospheric opacity (how much light it blocks) has been estimated at 10.8 tau as of Sunday morning — the 2007 storm only reached about 5.5 tau. This is roughly equivalent to the incredible smogs we’ve seen in China. Because of this, the bot cannot use its solar panels to recharge.

The storm has grown to over 18 million square kilometers (7 million square miles) since its detection. Such storms aren’t extreme for Mars, but they are infrequent. NASA doesn’t yet fully understand how they form or build in strength, but they seem to be self-reinforcing — a feedback loop that amplifies itself as it grows. Such storms can last up to several months at a time.

This dust blanket could be what makes or breaks Opportunity’s resolve.

Dusty but not yet dead

Opportunity.

You could say it’s an Opportunity to show what you’re made of, little rover!
Image credits NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

I say that because the dust is both a boon and a curse for Opportunity as of now. The rover’s main problems are that it cannot recharge (its solar panels are dusted over, and there’s not enough sunlight) and that communication with ground control is spotty at best (radio signals can’t pierce through the storm).

But the dust also hides a silver lining. Data beamed back by the rover shows its internal temperature is roughly stable at about minus 29 degrees Celsius (minus 20 Fahrenheit). The dust storm — which retains heat — seems to be insulating Opportunity from the extreme temperature swings on Mars’ surface. It’s not an ideal temperature by any means, but it’s still not as bad as it could get.

The team’s worst fears right now is that if the rover experiences cold temperatures for too long, it might damage its batteries. This fate befell Spirit, Opportunity’s twin craft in the Mars Exploration Rover mission, in 2010. Engineers plan to use the network to monitor and administer the rover’s energy levels in the following weeks — they need to somehow save as much battery charge as possible while keeping the rover from getting too cold. It has onboard heaters for this purpose, but they drain a lot of energy. One idea the team is considering is activating other equipment to expel energy, which would heat up the bot.

Science operations have been temporarily put on hold for sunnier days. Mission control has requested additional coverage from NASA’s Deep Space Network, a global system of antennas that talks to all the agency’s deep space probes, in an effort to maintain contact with Opportunity.

But I wouldn’t count Opportunity out just yet. It has proved its mettle aplenty in the past. Not only has it gone through dust storms before, but it made it with surprising gusto — the rover has accrued 15 years in the line of duty despite only being intended to last 90 days.

So hang in there little buddy, and don’t let the cold bite your batteries.

The new Li-ion battery developed by researchers in China capable of operating at -70 degrees C. Credit: Yongyao Xia and Yonggang Wang.

New lithium-ion battery operates at -70 C, a record low

Chinese researchers devised a lithium-ion battery fitted with organic electrodes that still functions at -70°C, a new record low. At this kind of temperature, and even higher, most lithium-ion batteries — which power everything from smartphones to Tesla Roadsters — lose their ability to conduct and store energy.

The new Li-ion battery developed by researchers in China capable of operating at -70 degrees C. Credit: Yongyao Xia and Yonggang Wang.

The new Li-ion battery developed by researchers in China capable of operating at -70 degrees C. Credit: Yongyao Xia and Yonggang Wang.

Once temperatures dip below a certain threshold, most batteries drastically lose performance. For instance, at -20°C lithium-ion batteries perform at only 50% of their optimal level. At -40°C, the same batteries only have 12% of their room temperature capacity. This can spell trouble in frigid environments like in some parts of Canada or Russia, where temperatures can plunge below -50°C, nevermind outer space where thermometers can measure an ungodly -157°C.

The main reason why cold disrupts lithium-ion batteries has to do with the electrolyte, which is the chemical medium responsible for carrying ions between electrodes (the positively charged cathode and the negatively charged anode). When it gets cold, the electrolyte in most lithium-ion batteries lose some of its capacity to conduct charge and the electrochemical reactions that occur at the interface of the electrolyte and electrodes are hampered.

This is typically the kind of trouble you run into when using ester-based conventional electrolytes. But battery researchers at the Department of Chemistry of Fudan University in Shanghai, China, took an alternative route. They also used an ester-based electrolyte but chose one that has a super low freezing point, enabling it to conduct charge even at extremely low temperatures. Then, for the electrodes, the scientists chose organic compounds: a polytriphenylamine (PTPAn) cathode and 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA)-derived polyimide (PNTCDA) anode. The advantage of such electrodes over those typically employed in Li-ion batteries is that there is no need for intercalation — a process where ions are continuously integrated into their molecular matrix but which slows down as it gets colder and colder.

Experiments suggest that “the rechargeable battery can work well at the ultra-low temperature of -70 degrees Celsius,” according to Dr. Yong-yao Xia, lead author of the new research published in the journal Joule. 

Previously, other researchers have tried to avoid having their batteries fail in the cold by developing special additives or by externally heating the batteries. Some have even used liquefied gas electrolyte, but these sort of workarounds add extra weight and can be expensive. The electrodes used by Xia and colleagues, on the other hand, cost only a third of the price of electrodes in typical Li-ion batteries.

“Compared to the transition-metal-containing electrodes materials in conventional lithium-ion batteries, organic materials are abundant, inexpensive, and environmentally friendly,” Xia says.

Next, the team will focus on improving the battery, whose specific energy is still rather low compared to lithium-ion batteries available on the market. They would also like to tweak the assembly process which could use optimizing.  “But even though it has low specific energy, it provides the most promising potential in special field applications,” Xia says.

Scanning electron microscope images show an anode of asphalt, graphene nanoribbons and lithium at left and the same material without lithium at right. Credit: Rice University.

Scientists add asphalt to lithium batteries that charge up to 20 times faster

Just a touch of asphalt is enough for high-capacity lithium metal batteries to charge 10 to 20 times faster than the commercially available lithium-ion variety. Additionally, the novel batteries last longer and are safer than current alternatives.

Scanning electron microscope images show an anode of asphalt, graphene nanoribbons and lithium at left and the same material without lithium at right. Credit: Rice University.

Scanning electron microscope images show an anode of asphalt, graphene nanoribbons and lithium at left, and the same material is shown without lithium at right. Credit: Rice University.

These findings were reported by a group of scientists at Rice University led by chemist James Tour. The team used porous carbon made from an asphalt derivative — specifically, untreated gilsonite — to develop the anode for their high-capacity battery. The asphalt was mixed with conductive graphene nanoribbons, and the composite was coated with lithium metal through electrochemical deposition.

When put to the test, the battery exhibited a discharging/charging rate of 20 mA/cm2 — 10 times faster than that of typical lithium-ion batteries (LIBs). The discharge rate was also up to 20 times faster than LIBs, the authors reported in the journal ACS Nano. What’s more, the device exhibited stability even after more than 500 charge-discharge cycles.

“The capacity of these batteries is enormous, but what is equally remarkable is that we can bring them from zero charge to full charge in five minutes, rather than the typical two hours or more needed with other batteries,” Tour said in a statement.

Applications requiring high-power density, as well as rapid charge and discharge could make good use of such devices. Electric cars, which are getting cheaper and rising in sales, will need a fast charging infrastructure if they’re ever to take off, for instance. When it takes just a few minutes to charge electric cars with enough power for them to drive hundreds of miles, their popularity will increase exponentially.

Due to their exceedingly high specific capacity and extremely low electrochemical potential, lithium metal batteries have been on the minds of scientists for some time. What prevented them from reaching the market is an inherent flaw concerning dendrite formation. These are mossy deposits which invade the battery’s electrolyte, which with time short-circuit the anode and cathode. When this happens, the battery fails and can even explode. Up until now, this has remained a challenge for its practical applications.

The asphalt-derived carbon prevents any dendrite formation, however. Previously, Tour and colleagues showed that lithium metal batteries whose anode is composed graphene and carbon nanotubes also prevented the formation of dendrites. The new asphalt composite anode, however, is far simpler and cheaper to make.

“While the capacity between the former and this new battery is similar, approaching the theoretical limit of lithium metal, the new asphalt-derived carbon can take up more lithium metal per unit area, and it is much simpler and cheaper to make,” he said. “There is no chemical vapor deposition step, no e-beam deposition step and no need to grow nanotubes from graphene, so manufacturing is greatly simplified.”

An aqueous lithium-ion battery is a lot safer than what's currently available on the market. Credit: Control Hazards.

New water-based lithium-ion battery will never explode in your face

An aqueous lithium-ion battery is a lot safer than what's currently available on the market. Credit: Control Hazards.

An aqueous-based lithium-ion battery is a lot safer than what’s currently available on the market. Credit: Control Hazards.

Collaborating with the military, University of Maryland researchers made a 4-volt lithium-ion battery that runs on an aqueous-based electrolyte. With no organic solvents in its composition, the battery can’t possibly ignite or explode like the typical non-aqueous lithium-ion variety. OK, now someone please send Samsung a memo.

“In the past, if you wanted high energy, you would choose a non-aqueous lithium-ion battery, but you would have to compromise on safety. If you preferred safety, you could use an aqueous battery such as nickel/metal hydride, but you would have to settle for lower energy,” says co-senior author Kang Xu, a lab fellow at the U.S. Army Research Laboratory specializing in electrochemistry and materials science.

“Now, we are showing that you can simultaneously have access to both high energy and high safety.”

Safer batteries for everyone

This video shows how when punctured repeatedly with a nail, a four-volt aqueous lithium-ion battery initially maintains its voltage, and no fire, smoke, or explosion occurs. This contrasts with the instantaneous short-circuit and explosive risk of an analogous non-aqueous battery.

Previously, the same team demonstrated an aqueous battery back in 2015. That version could deliver only 3 volts but, worst of all, also had a very poor cycling ability due to the so-called ‘cathodic challenge’. The problem with using salt-water solutions as electrolyte is it messes up one of the two ends of the battery (anode or cathode electrode).

Not only was the aqueous-based lithium-ion battery upgraded to 4 volts, it also features an innovative coating on the electrode’s surface that avoids its degradation.

The hydrophobic coating is a carefully fashioned gel that expels the water molecules from the electrode’s surface. When the battery is charged for the first time, the coating decomposes and forms an interphase that permanently separates the solid anode from the liquid electrolyte.

Moreover, the interphase greatly enhances water’s rather narrow electrochemical stability window, which is ∼1.23 V under thermodynamic equilibria. With the electrodes kinetically protected, the researchers manage to come up with a battery that operates beyond the above limit.

It’s important to mention at this point that the electrolyte has to also contain salt. The video below shows a lithium metal reacting violently with water, but slowly and undetectably with water-in-salt electrolyte (sWiSE).

Protected from debilitating reactions with water, the battery can now also use anode materials with desirable properties such as graphite or lithium metal that offer better energy density and cycling ability.

“The key innovation here is making the right gel that can block water contact with the anode so that the water doesn’t decompose and can also form the right interphase to support high battery performance,” says co-senior author Chunsheng Wang.

The greatest upside of this kind of battery is safety. It’s basically impossible for it to catch fire or down-right explode, unlike typical lithium-ion batteries based on highly flammable organic solvents. Just take a look at this Stanford study which visually shows how thermal runaway causes battery components to melt at temperatures exceeding 1,085°C.

Even if the battery is punctured, the interphase layer reacts with the lithium or lithiated graphite anode preventing any smoking or fire, the authors reported in the journal Joule. 

There are, of course, drawbacks. One would be cycling ability, which severely degrades after 100 charges. Wang and colleagues, however, think they go get to 500 cycles or more which would make the battery competitive with organic electrolyte batteries.

“This is the first time that we are able to stabilize really reactive anodes like graphite and lithium in aqueous media,” says Xu. “This opens a broad window into many different topics in electrochemistry, including sodium-ion batteries, lithium-sulfur batteries, multiple ion chemistries involving zinc and magnesium, or even electroplating and electrochemical synthesis; we just have not fully explored them yet.”

Pictured: Seokheun Choi. Credit: Binghamton University, State University of New York.

Scientists develop spit-activated battery

Pictured: Seokheun Choi. Credit: Binghamton University, State University of New York.

Pictured: Seokheun Choi. Credit: Binghamton University, State University of New York.

A team at the Binghamton University, State University of New York has taken microbial fuel cells to the next level. They’ve found a way to make tiny paper-based microbial fuel cells that activate only when the user adds a few drops of saliva. Once activated, the battery delivers power. It’s in minute amounts but still enough to power critical electronics like point-of-care diagnostic biosensors.

“Typically, those applications require only several tens of microwatt-level power for several minutes, but commercial batteries or other energy harvesting technologies are too expensive and over-qualified. Also, they pose environmental pollution issues,” said Seokheun Choi who Assistant Professor at Binghamton University Electrical and Computer Science.

Spitting energy

A microbial fuel cell or MFC harnesses the power of respiring microbes to convert organic substrates directly into electrical energy. A normal fuel cell transforms chemical energy into electricity using Redox (oxidation-reduction) reactions. Microbes naturally oxidize and reduce organic molecules because bacterial respiration is essentially one big redox reaction in which electrons are being moved around.

MFCs aren’t by far the most appealing power generators since reactions can take some time to kick off and not a lot of electricity can be produced. They’re great, however, for niche applications like converting waste into useful energy. They’re also very reliable off-grid power generators when you need to monitor things such as water quality in places where other means are practically impossible.

The Binghamton MFC is innovative for a couple of reasons. It’s very portable and cheap, essentially being made of paper with a bacterial substrate. The cell is freeze-dried which enables long-term storage of cells without degradation. To activate the cell, one only needs to add some saliva, a resource that is always readily available.

As far as power density goes, it’s only a few microwatts per square centimeter. But even such tiny power can be enough to use essential electronics in remote areas found in developing countries. When 16 such MFCs were connected in series on a single sheet of paper, the power was enough to light an LED.

Choi and colleagues are now looking to improve power performance so the spit-activated MFC can power applications in the hundreds of milliwatts range.

Findings appeared in the journal Advanced Material Technologies.

 

Not the batteries you're looking for

Solid energy — how batteries power the world

If you can’t plug it in but need it powered, you better have a battery handy. Often overlooked, they keep our world in working order. But what are they? How do they work? And how come you can use a lemon to power a light bulb? Let’s find out.

Not the batteries you're looking for

Hint: one of these things is not a battery.
Image credits Tookapic / Pixabay.

Technology lets us do some pretty amazing stuff. Talking on the phone in the middle of nowhere, for example. Or reading these words even though I’ve just finished typing them, halfway across the world, a few seconds ago. You can whoosh through the sky in a chair, which probably drives birds green with envy. We’ve sent people and robots to outer space, a place that will freeze you, choke you, and give you the mother of all sunburns while you’re drifting along lazily because your legs aren’t any good there — all in complete safety. Doing all this eats up energy, however. A lot of energy.

Herein lies the issue. Because nature is sometimes annoying, you can’t carry around electricity like you can do with water — electricity either flows or doesn’t, you can’t fill up a bucket with it and use it later. Generators, on the other hand, don’t fit inside an iPhone, and strapping power-lines to a space shuttle kinda defeats its purpose. Thankfully, there’s a way you can carry power around with you.

Annoying when they run out in your mouse, thrown away more often than you can remember but making the world go round, let’s take a look at the unsung heroes of the modern day: batteries.

What batteries are made of

Electricity can’t be stored as such, but what you can do is transform it into another kind of energy and store that — which is exactly what batteries do. They store energy in chemical bonds and release it when needed as a flow of electricity.

It sounds complicated, but they’re actually surprisingly simple devices — you probably have the materials to build a (fairly weak) battery lying around your house. Batteries are formed from voltaic cells. Each is built using a positive negative electrode (cathode and anode), something to isolate the two (a separator), and something to bridge them — a conductive medium known as an electrolyte which gives ions a way to flow between the electrodes.

Zinc Battery Section

Image credits Mcy Jerry / Wikimedia.

The cathode is submerged in the electrolyte, forming what’s called a positive half-cell. The anode and electrolyte combo forms a negative half-cell. These half-cells don’t do much on their own, but their atoms very much want to mingle — which is exactly why you need a separator (we’ll get to that in a moment).

Today, most batteries you’re likely to see (with the exception of car batteries) are known as “dry”, meaning they use a paste electrolyte which is less likely to leak. While they maintain a more or less constant structure across the board, materials vary widely. Zinc/Carbon batteries are ubiquitous non-rechargeable batteries as they’re laughably cheap to manufacture. Zinc/Manganese Dioxide with a Potassium Hydroxide electrolyte is also commonly used mix as it offers a good price-weight-output ratio.

Nickel variants (with Cadmium or metal hydride cathodes) are common for rechargeable batteries as they can sustain a large number of cycles even if they’re limited in regards to energy density — metal hydride cathodes offer better output at the expense of cycle life. And of course, there’s the Lithium Ion variety used in your phone — these are more expensive to produce but they have solid output and low weight.

How batteries work

The electrolyte allows the two ends of the battery (the electrodes) to trade ions (charged atoms) in a Redox reaction. Cations ( + charged ions) migrate to the anode where they dump excess electrons, leading to an electron build-up at the anode over time.

Since all electrons hold the same electrical charge they generally don’t really like one another. So they do all they can to get as far away from their kind as possible. In a battery, the only place they can go and do that is the cathode. This buildup — electrons wanting to move from one point to another — creates an electrical potential in the battery.

They can’t, however, move freely about through the electrolyte. Electrons need either a carrier in the form of ions to shuttle them to the other end of the battery, or for the cathode and anode to touch to disperse in a short-circuit. Since no ion in its right mind wants to move towards a point of the same electrical charge and the separator keeps the two electrodes well, separated, all those electrons are just dying for a way to flow to the cathode.

Then you come in the picture to deliver them from anguish. When you socket the battery in a computer mouse, for example, you complete its electrical circuit by bridging the anode and cathode together — giving the electrons a way to flow.

This is electricity.

What batteries can’t do

The hook with chemically storing energy is that over time the cathode becomes depleted of ions, which are now all snugly bound on the outside of the anode. This is why batteries run out.

For some of them (called secondary charge or rechargeable batteries) this process can be reversed by pumping electricity back into the battery. These are built from materials that can store an electrical charge, and need to be charged before their first use. After use, the influx of electricity pushes cations ( + charged ions) towards the anode where they dump excess electrons, refreshing the electrodes.

Over time, they lose their ability to hold a charge. One thing to look out for in secondaries is bloating — exposing the battery to extreme temperatures, extreme temperature shifts, as well as overcharging (which overheats the battery), can make them bloat. If the seals break they start leaking acid. Not good. The lead-acid battery that runs your car is a rechargeable battery, for example.

jumper-cables

Thankfully re-chargeable.
Image credits StockSnap / Pixabay.

Primary charge batteries, on the other hand, use materials that can generate a change. They can be used right after assembly and don’t require charging. In theory, you could re-charge them. However, the chemical reactions that power them are very hard to reverse so it’s usually not economically viable, however. It’s also r-e-a-l-l-y unsafe, since the casings aren’t able to take the much higher thermal strain. Manufacturers strongly recommend against trying to do so for good reason. Results vary from “a bit of charge” to “fire”, “acid leaks everywhere and fire”, to “fireball-belching, acid-spewing, boom“.

So don’t do that. Don’t.

Backyard power

There’s actually a lot of wiggle room in what materials can form a battery. A Magnesium/Copper/Lemon cell can reach a better output than run-of-the-mill batteries (1.6 volts compared to 1.5 volts). Potato batteries have even been suggested as a viable source of power for people living off-grid. As long as you have a type of acid and two different metals available, you can make a battery — though the output will vary quite wildly from system to system.

So grab an LED, some fruit, and go experiment. Maybe you’ll hit on the battery of the future

Snap! Back together. Credit: YouTube

Self-healing battery pulls itself back together if you cut it in half — still delivers electricity

Snap! Back together. Credit: YouTube

Snap! Back together. Credit: YouTube

Simple electronics made of micro-sized magnetic particles dispersed inside conductive materials can pull themselves back together using magnetic attraction if fractured.

“It’s actually a pretty simple concept,” said Amay Bandodkar at the University of California, San Diego, who led the research team. “This started when we asked ourselves, how can we simply implement a self-healing feature into existing electronics without making them unnecessarily complicated or expensive? This was our solution.”

Bandodkar and colleagues experimented with various self-healing batteries, sensors, and circuits. Previous self-healing electronics which we showcased use conductive fluids that are released from capsules when a crack or rupture is detected to fill in the blanks. The UCSD team, however, used conductive graphite material mixed with small magnetic particles made from neodymium magnets. Both materials are dirt cheap and readily available. You can even get them from a supermarket, Bandodkar said.

Employing this magnetic mixture as a printing ink, the team 3-D printed simple electronics before subjecting them to a strong electromagnetic field. This is to ensure that all the microparticles are aligned in the same direction and, if displaced by a rupture, glue back together in their original orientation.

You can get an idea of how all of this works in the demonstration videos below.

https://www.youtube.com/watch?time_continue=94&v=bO377ZglVTU

https://www.youtube.com/watch?v=Eu9nrKbbwBI

It’s worth noting that while the batteries and circuits can self-heal and continue operating normally afterward, cracks and fracture signs still show. You might not think much of that, but the other downside is that these electronics are essentially magnetic and in many situations, that’s not acceptable. But Bandodkar is one step ahead of us and said the next version will come with electromagnetic shielding so users can breathe easily that their hard drives aren’t in peril.

via Popular Mechanics

New material acts as both battery and supercapacitor. Credit: William Dichtel, Northwestern University

New storage device combines attributes of both capacitors and batteries

New material acts as both battery and supercapacitor. Credit: William Dichtel, Northwestern University

New material acts as both battery and supercapacitor. Credit: William Dichtel, Northwestern University

A novel nanomaterial combines the best of batteries and supercapacitors. The new storage device has a high energy density but also fast charge and discharge time. The Northwestern University researchers who were responsible for the new hybrid device say electric cars could charge significantly faster and improve their driving range using this technology.

In it’s simplest form, a capacitor is made of two parallel plates with a dielectric material in between them, keeping them apart. When a voltage is applied over the two plates an electric field is created, with one of the plates being positively charged while the other is negatively charged. Thus, charge or energy becomes stored in the capacitor in the form of  an “electrostatic field” between the two plates.

Once it’s charged, a capacitor basically stores that energy like a battery — the bigger the capacitor the more charge you can store. For instance, there are tiny plastic capacitors in your computer to supply power to the integrated circuits but also ultracapacitors that are powerful enough to power a commuter bus.

In a supercapacitor, there is no dielectric between plates; rather, there is an electrolyte and a thin insulator such as cardboard or paper. When you charge a supercapacitor, ions build on either side of the insulator to generate a double layer of charge. So, although they’re limited by a lower voltage (otherwise the electrolyte is destroyed), supercapacitors can hold much more energy than a capacitor.

While batteries and capacitors may seem very similar, there are crucial differences between the two. The potential energy in a capacitor is stored in an electric field, where a battery stores its potential energy in a chemical form.

Chemical storage of energy yields greater energy densities (capable of storing more energy per weight) than capacitors. However, when a battery is discharging it can be slower than a capacitor’s ability to discharge because there is a latency associated with the chemical reaction to transfer the chemical energy into electrical energy.

The major takeaway is that batteries store energy in chemicals while capacitors store them in electric fields. Also, capacitors charge and discharge quickly (at least ten times faster), last longer, but can store a lot less energy per weight than batteries.

Combining the best of these worlds might yield significant benefits, yet this has always proven to be an engineering challenge. Northwestern University chemist William Dichtel and colleagues claim they’ve edged really close to achieving a reliable hybrid by mixing covalent organic frameworks (COFs) — a strong and stiff polymer littered with tiny pores — and a very conductive material. COFs are also inexpensive and easy to make compared to carbon-based materials for pseudocapacitor electrodes.

“COFs are beautiful structures with a lot of promise, but their conductivity is limited,” Dichtel said. “That’s the problem we are addressing here. By modifying them — by adding the attribute they lack — we can start to use COFs in a practical way.”

The team devised a coin-sized battery cell starting from an electrode surface. Organic molecules are then carefully guided to self-assemble and condense into a honeycomb grid onto the substrate. In the resulting holes or pores, the researchers then deposited a conducting polymer. Each pore is very tiny, only 2.3 nanometers in width or roughly 40,000 times thinner than a human hair or sheet of paper. The COF, however, is full of these pores which add up to a lot of surface area.

Tests show that the nanomaterial can store roughly 10 times more electrical energy than the unmodified COF, and it can get the electrical charge in and out of the device 10 to 15 times faster. Stability was also reported to be outstanding as the material performed reliably even after 10,000 charge/discharge cycles, as reported in ACS Central Science.

“It was pretty amazing to see this performance gain,” Dichtel said. “This research will guide us as we investigate other modified COFs and work to find the best materials for creating new electrical energy storage devices.”

Tesla just changed one word in its mission statement – and it’s a big change

Earlier this week, Tesla and SpaceX founder and mastermind Elon Musk tweeted that he is contemplating what’s next for Tesla, after accomplishing all the objectives they set out to do in 2006. But while the official statement is still yet to be announced, a subtle change speaks greatly about their plans for the future: “sustainable transport” has been changed to “sustainable energy”.

As was previously spotted by Bloomberg, the previous mission statement looked like this:

Now, it looks like this:

Why this matters

Tesla has already been making innovations in sustainable cars for years already, and the next logical step is to move in renewable energy – namely solar energy. Specifically, we’re looking towards their acquisition of SolarCity, and this makes a lot of sense. If you have an electric car you’d charge at home or some charging station, then you’re going to need more electricity, and solar is the easiest renewable to incorporate in urban areas. As Bloomberg and ScienceAlert reported, this is more than a business move. This could very well pave the way for a new solar/car revolution.

“Tesla Motors Inc.’s bid to buy the biggest US rooftop solar installer has little to do with selling cars. Rather, it’s about solving two of the biggest problems standing in the way of the next solar boom. And perhaps a good deal more,” Bloomberg reporter Tom Randall wrote in an article last month.

Normally, we wouldn’t care about things like this – but this is not just about a company looking to expand into a different market. What they’re looking for is to merge three big puzzle pieces into one sustainable conglomerate. Those pieces are cars, solar energy, and batteries. As we previously reported, Tesla has been diving into the battery world for quite a while, and while SpaceX has more ambitions in outer space, Tesla seems convinced to take care of things down here on Earth.

Origami battery that runs on a few drops of water could revolutionize biosensors

An engineer from Binghamton University, State University of New York designed a new disposable battery that could power biosensors and other small devices in areas where conventional batteries are just too expensive. The battery only uses one drop of dirty water to generate energy. But the best part — it folds up like an origami ninja star.

Image credit: Jonathan Cohen/Binghamton University.

Seokheun Choi, assistant professor of computer and electrical engineering at Binghamton University, working with two of his students developed the new device that’s powered by the bacteria found in dirty water. This isn’t Choi’s first origami battery — his first design was shaped like a matchbox and consisted of four modules stacked together. The star version is made out of eight small batteries connected in a series, measures in at around 6.35 centimeters (2.5 inches) wide and has a better power output and increased voltage than the first one.

“Last time, it was a proof of concept. The power density was in the nanowatt range,” said Choi. “This time, we increased it to the microwatt range. We can light an LED for about 20 minutes or power other types of biosensors.”

Paper-based biosensors are currently used for pregnancy and HIV tests, but their sensitivity is limited says Choi. His battery could allow these sensors to employ fluorescent or electrochemical biosensors with a much better accuracy, even in developing countries.

“Commercially available batteries are too wasteful and expensive for the field,” he said. “Ultimately, I’d like to develop instant, disposable, accessible bio-batteries for use in resource-limited regions.”

The battery unfolds into a star with one inlet at its center and the electrical contacts at the points of each side. After adding a few drops of dirty water on the inlet and the device can be opened into a Frisbee-like shape, allowing each of the eight fuel cells to function. Each module is a sandwich of five functional layers with its own anode, proton exchange membrane and air-cathode.

While Choi’s first battery could be produced for about 5 US cents, the star is a bit more expensive — roughly 70 US cents. This is because the battery is also made with carbon cloth for the anode and copper tape in addition to the filter paper. The team plans to produce a fully paper-based device that has the power density of the new design with lower price tag.