Lithium-ion is just the beginning. Here’s a peek at the future of batteries

By the time Colonel Brent Wilson became base commander at Oahu’s Camp Smith, he’d been deployed in the Gulf and Iraq wars and led numerous defense operations in Kosovo. But the foe he faced at the Hawaiian base was different from any he’d seen on the battlefield as a Marine Corps helicopter pilot. He had to contend with an aging energy infrastructure regularly trampled by tropical weather.

The Crescent Dunes plant is a tremendous success story for U.S.-developed technology that is leading the world in solar energy storage

“The whole power grid was going down routinely and put us out of business,” explains Wilson who, at the time, was also part of the team responsible for defense operations throughout the Pacific. “You can’t really have that.”

But the battle against bad infrastructure also had an underutilized ally: Sunlight. Wilson started a campaign to install solar panels and industrial batteries that could keep the vital parts of the operation online when storms hit. That experience eventually helped springboard him into a second career: Selling batteries big enough to power your home off the grid.

The battery boom

The battery market has ballooned in the past several decades and is expected to increase by another 12% in the next five years, according to Mordor Intelligence. By 2025, it will be a $90 billion market. Over the past decade, companies like Tesla, Dyson, and Daimler have all made billion-dollar investments in the industry, either acquiring smaller companies or building new factories. If that classic scene from The Graduate were filmed today, the one-word career advice given to Dustin Hoffman’s character wouldn’t be “plastics,” it would be “batteries.”

Lithium ion battery

What will propel all that growth? Lithium-ion battery price decreases, personal electronics, and electric cars churning through them, and, among other factors, more homeowners and power companies looking to store solar and wind energy.

Along with that growth comes a lot of waste. Unfortunately, most batteries wind up in landfills. Recycling rates for lithium-ion cells are horrendous: About 5% for the United States and European Union. Researchers are finding ways to make lithium-ion batteries more recyclable, but even if that happens, we still need to change the habits of people and corporations who don’t recycle batteries at all and dispose of them by tossing them in the trash.

Further, some experts say there’s a limited amount of lithium available, although how limited is up for debate. The mining of it and cobalt (which is commonly used for a lithium-ion battery’s positive electrode) comes at a high environmental and human cost. Plus, cobalt’s price has risen notably in the past several years.

This all begs the question: Are there cheaper, more environmentally friendly batteries out there? Could we be using something better? What does the future hold?

A lot of people are researching the possibilities. Since the 1990s, more than 300,000 battery-related patents have been filed (more than 30,000 in 2017 alone). While a large percentage of these inventions are related to lithium-ion tech, plenty of work is being done on solid-state electrolyte, silicon-based anode, lithium-air, graphene and other options, some of which are eco-friendly, and others that are environmentally no better than lithium-ion but possibly more efficient.

While most of these new battery types probably won’t be marketed as widely as lithium-ion (at least in the next couple of decades), they can serve really big niche markets. Here are some of the popular ones.

Lithium iron phosphate

Soon after Col. Wilson retired from the military, executives from a solar panel company asked him to dip into his years of energy storage acquisition knowledge (the military is one of the world’s biggest battery users), take a trip to CES in Las Vegas, and survey the current crop of home batteries. After the trip, he created a giant spreadsheet to explain why he was dissatisfied with the options he saw. The best batteries were either overpriced for the average homeowner ($30,000-plus) or didn’t have enough power. He then worked with NeoVolta to create a line of batteries, which typically cost in the very low double digits.

Environmentally minded chem-heads will quickly tell you that lithium-iron-phosphate energy storage is just another type of lithium-ion battery, albeit one with some notable advantages: It’s cheaper, has more dense energy, longer life and won’t catch fire if the insides rupture (which can happen with lithium-ion batteries). The downsides? It’s extremely heavy (which is why it’s better if it’s sitting on your back porch and not in your phone), the case still has lithium in it, and the recycling pathway is unclear.

As such, few have adopted lithium-iron-phosphate batteries, making it tough to know how good their recycling rate is. Some researchers contend they are easier to break into component parts.

Lithium-sulfur

Some experts are betting on lithium-sulfur energy storage to replace lithium-ion since the batteries tend to be lighter and more energy-dense. Sulfur is also plentiful and cheaper.

What’s the difference between how lithium-ion and lithium-sulfur batteries work? Professor Linda Nazar, whose lab at Canada’s University of Waterloo has been studying lithium-sulfur batteries for the past 10 years, uses a parking garage analogy to describe the differences. Whereas the charging and discharging of a lithium-ion battery is like driving cars in and out of a parking garage, the lithium-sulfur battery is “almost tearing down the entire parking garage structure and then rebuilding it when you recharge the cell.”

The chemical reaction is akin to what happens in a lead-acid battery where there is a complete structural and chemical transformation. These “conversion” batteries have their own advantages and challenges. “They have the advantage of being able to store more electrons,” says Nazar. On the other hand, sulfur has relatively low conductivity and the volume of the batteries changes after discharging. The team at the University of Waterloo lab is tweaking the components in the battery to increase the cycle life and optimize the battery’s reactions. If some of the battery’s challenges are solved, Nazar envisions them being used in aviation as well as drones. The Zephyr planes and UAVs, which have flown accomplished some of the long electric-powered flights, often rely on lithium-sulfur batteries.

Sodium-ion

As it turns out, the periodic table element that’s so bad for your heart is pretty good for batteries. Research in sodium-ion batteries started in the 1970s, around the same time as lithium-ion energy storage. The two elements are neighbors on the periodic table. Then lithium-ion took off and sodium-ion was considered a less energetic also-ran for the next three decades.

“It looks like the best thing around,” says Nazar, whose lab also works with sodium-based energy storage. “Sodium-ion batteries give one the possibility of working with earth-abundant elements — positive electrodes made out of things like iron, manganese, and titanium — elements that are much lower cost. But getting that chemistry to work well is a challenge because it’s just not the same as lithium.”

Nazar notes that some companies don’t think it’s worth investing in sodium-ion batteries because the cost of lithium-ion batteries is dropping all the time.

“I think it is probably worth investing a lot of resources in sodium-ion batteries,” she says. “If there’s an a-ha moment that has sodium-ion batteries working really well, with high-energy density, that would be a huge step forward.”

Sugar

Believe it or not, you can run a battery on sugar like a toddler hopped up on cake pops. Sony first published research about the reaction in which maltodextrin is oxidized to create energy in 2007. Although the material availability and eco-friendliness of sugar batteries is much higher than lithium-ion ones, the voltage created by their chemical reaction is notably lower. So, you’ll probably want to hold off feeding your Tesla a box of Crunchberries.

Although the original concept first appeared in 2007, the sugar battery concept still has some juice left in it. In 2016, a Massachusetts Institute of Technology team led by Professor Michael Strano created a device called the Thermopower Wave, which is much more efficient than previous sugar battery incarnations and can power a commercial LED light. This is an exciting development because sugar is highly abundant, so If we can figure out a viable way to produce these batteries, we could presumably scale that technology up quickly. Unfortunately, commercial availability is likely several years away.

Flow

A flow battery is structured differently than most other ones: Instead of packing a bunch of reactive materials together in one unit (like normal batteries do), flow batteries store reactive liquids in separate containers and then pump them into the system to create energy. They’re also huge and designed for grid energy storage — not for electronics and things that can fit comfortably in the palm of your hand.

The original flow battery reportedly weighed 1,000 pounds and was invented in the late 19th century to power the cleverly named French airship “La France.” Interest in the modular energy storage has waxed and waned since then.

“I think what’s really driving an explosion and interest in flow batteries is not so much about making the next generation of batteries for phones or computers, but medium-to-large scale energy storage,” explains Timothy Cook, a professor of chemistry at the University of Buffalo. So, unless you’re building a steampunk cell phone, it’s unlikely you’re going to be carrying around any flow batteries activated with microscopic pumps. However, as more homes install solar power, the market for “personalized energy” storage will grow.

While making lithium-ion batteries more powerful means increasing the size of the battery, the design of the flow batteries makes it possible to increase energy by increasing the size of the liquid reservoirs. San Diego Power and Electric recently installed one that can power 1,000 homes.

“You don’t have to change any of the dimensions of the membrane [where the chemical reaction occurs], you just have to flow the larger volume of liquid through it for a longer time and you can extract that energy out,” explains Cook. “So it’s much much much easier to scale up or scale down or you can basically customize it to the installation.”

Flow batteries also have many more charging cycles than most batteries. The ability to replace the liquids or replace other modular parts means that the potential life of a battery is almost indefinite.

Even though companies currently sell industrial-size flow batteries, professor Cook doesn’t expect widespread acceptance for another five to 10 years. He even imagines a day when electric cars might use the tech. Cook describes a car pulling up to a “gas station,” discharging the spent electrolyte, and then refilling with a freshly charged one. Instead of waiting a half-hour for your car to reboot, the wheels can be spinning again in a matter of minutes. But, of course, that future is way down the road.

Paper

Making a battery out of paper has many advantages: It’s thin, flexible, and, if fabricated with the right materials, biodegradable. A team at Stanford University developed early paper batteries by coating thin sheets with a carbon and silver saturated ink. More recently, eco-heads have grown excited about the batteries being developed at Binghamton University. Professor Seokheun “Sean” Choi has made a few different incarnations of it, including one powered by spit — or more scientifically, human saliva — and another powered by bacteria. A recent incarnation of the biobattery developed by Choi and Professor Omowunmi Sadik uses poly (amic) acid and poly (pyromellitic dianhydride-p-phenylenediamine) to make the energy sources biodegradable.

“Our hybrid paper battery exhibited a much higher power-to-cost ratio than all previously reported paper-based microbial batteries,” Choi said when the innovation was announced. Although the commercial use of these eco-friendly paper batteries has been limited given their low electric output (one can power an LED light for about 20 minutes), researchers hope to see them used in electronics, wireless devices, medical applications like pacemakers, aircraft, and automobiles. Choi has written a paper about utilizing them as single-use power sources for point-of-care diagnostic tools in developing countries where batteries may not be readily available.

Air

Air can actually be electric, and not just in that moment when you pop your collar after a Phil Collins tune comes booming out of your Ferrari’s speakers. Zinc-air batteries, which are about the size of Smarties candies and powered by the reaction between oxygen and zinc, have been used in hearing aids for many years. Zinc is also cheap and abundant, making the technology economical as well as eco-friendly.

But there are limitations when trying to make this tech rechargeable. Dendrite crystals can form during charging and short out the battery. Ways have been tested to replace the zinc such as “mechanically recharging” the battery by physically replacing the materials, an approach that has been tried in Singapore’s electric buses. Numerous other experiments have been attempted with lithium-air and metal-air batteries with varying degrees of energy density, power level, and cost. Over the past decade, Tesla has filed several patents related to charging lithium-air batteries, so their potential may exist far beyond your hearing aids.

Iron

A few years ago, University of Idaho chemistry professor Peter Allen started expressing his fascination with battery science on YouTube. Almost immediately he found that viewers really respond to battery material, which inspired him to build a rechargeable iron battery as an educational demonstration. That project has led to more than 100 demonstration videos explaining the steps, problems, and learnings of an educational battery project.

“I don’t want to pitch myself as a battery expert, per se,” acknowledges the professor, whose area of expertise is biological chemistry. In doing the YouTube videos, he realized that there was a lot to be taught and learned by building a relatively cheap do-it-yourself battery.

“Parts of the iron battery technology have been around for 100 years, so I think a lot of folks who might come into this with a lot of foreign knowledge would just say, ‘Well, that’s that’s trodden ground — there’s nothing to be found there,’” he says. “But being a little naive, I walked into it and said, ‘Well, let’s try it, you can find something interesting anyway.’”

After two years, more than 30 battery variations, and a lot of help from undergraduate students, Allen has learned how to balance the liquid and solid materials to create an optimal amount of energy density but with low power.

“Then we got into this whole question of: ‘If you have a chemistry that works, but works slowly, how do you speed it up?’”

Even if the team solves that challenge, current technology dictates that the best applications for an iron battery will likely be a neighborhood microgrid energy storage unit or solar farm power capture, given the space required and the speed of energy sent from the unit.

Who will win?

Will Allen’s iron battery ever be commercially viable? He isn’t sure that he team’s current findings, which have been published in a scientific journal, will get them there.

Having reviewed numerous battery inventions, he realizes only a few of them will actually make it to market. In scientific research, he explains, there’s a “valley of death.”

“You have the basic research that comes up with something really cool,” he says. “There’s a question of whether it can be commercialized. And there’s no money to ask that question.” Researchers who find enough money to answer that initial question will then, if they’re lucky, find investors who want to refine and commercialize the idea. “But there’s a gap between the basic research and necessary refining to make a battery commercial.”

In 2019, venture capitalists sunk $1.7 billion into battery startups, with 1.4 billion of it going to lithium-ion related research. But flow batteries, zinc-air, liquid metal, and many other technologies also got written checks. While lithium-ion energy storage will likely dominate energy storage for at least another 10 years, many others already look like they’ll power their way out of the valley of death.

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