Batteries Still Suck, But Researchers Are Working on It


Better batteries mean better products. They give us longer-lasting smartphones, anxiety-free electric transport, and potentially, more efficient energy storage for large-scale buildings like data centers. But battery tech is frustratingly slow to advance, due to both the chemical processes involved and the challenges that exist around commercializing new battery designs. It remains incredibly tough for even the most promising battery experiments to find their way out of research labs and into the devices we carry.

That hasn’t stopped people from trying. In recent years researchers and technologists have presented a variety of ways in which the materials in rechargeable lithium batteries—the kind in your phone right now—can be tweaked to improve battery density and, more importantly, battery safety. These technologies aren’t going to make it to market in time for the Next Big Product Launch, but as we watch our phones slurp up the last dribble of power at the end of a long day, we can dream about the future.

Battery Basics

Complex battery technology can make even the most tech-savvy person feel like they need a PhD in chemistry to make sense of it, so here’s an attempt to break it down. Most handheld and portable electronics use lithium ion batteries, which are made up of an anode, a cathode, a separator, an electrolyte, a positive current, and a negative current. The anode and cathode are the “ends” of the battery; a charge is generated and stored when the lithium ions (carried by the electrolyte) move between the two ends of the battery.

Lithium ion is still considered to be one of the lightest and most efficient battery solutions. But because it only has so much physical energy density, there are limits to how much of a charge it can hold. It’s also sometimes dangerous: if something goes awry with the separator, and electrodes come in contact with one another, the battery starts to heat up. And liquid electrolytes are highly flammable. This often is what leads to exploding batteries. “[Electric] car crashes, Samsung phones–those are mostly thermal runaway problems,” says Partha Mukherjee, who researches energy storage and conversion at Purdue University’s school of mechanical engineering.

Some of the solutions being worked on now introduce alternative materials that increase the efficiency and thermal stability of batteries—for example, using silicon nanoparticles for the anode instead of commonly-used carbon graphite, or using solid electrolytes instead of liquid ones.

Silicon Anode

Typically, graphite anode materials are used in lithium ion batteries. But microscopic silicon particles have been emerging as a more efficient replacement for graphite–and at least one company thinks this technology will come to market within the next year.

“An atom of silicon can store about 20 times more lithium than atoms of carbon,” says Gene Berdichevsky, the CEO of California-based Sila Nanotechnologies and an early Tesla employee. “Essentially, it takes fewer atoms to store the lithium, so you can have a smaller volume of material storing the same amount of energy” as a typical graphite material. He says Sila Nano will launch its first battery product for the consumer market early next year. At launch, Berdichevsky expects to see 20 percent improvement in battery life over traditional lithium ion batteries.

Others have already pursued a silicon anode as a solution to today’s battery problems; there’s an entire consortium dedicated to the cause, which includes the Argonne, Sandia, and Lawrence Berkeley National Laboratories. Berdichevsky and Sila co-founder and CTO Gleb Yushin say what sets their research apart is that they believed they’ve solved the “expansion” problem. Silicon has a tendency to swell, essentially destroying batteries with every charge. Sila’s tech involves tucking the microscopic silicon particles into tiny spherical structures inside the battery that leave some room for the silicon to expand.

That may sound like a simple solution, but Berdichevsky says it’s been anything but. “It’s taken us seven years and 30,000 iterations in our lab, no exaggeration, to develop a method for creating this structure,” he says. Berdichevsky also says the challenge with developing any battery tech is to create something that “doesn’t make one thing better while making other things worse, which is the nature of academia because it’s happening in a lab.”

Lithium Metal

Batteries made with lithium metal have a reputation to overcome: soon after they were commercialized in the late 1980s by Moli Energy, they caused enough fires to warrant a massive recall of all of the cells on the market. But Mukherjee at Purdue University, and others, say lithium metal batteries have been enjoying some renewed interest over the past five years. New designs are emerging which use lithium metal for the negative anode part of the battery instead of graphite, enabling the battery to hold a higher charge.

Much of this interest in higher-charge batteries has been driven by the growth of electric cars; as ARPA-E researchers noted in this paper published in Nature last December, “the present lithium ion material platform” is unlikely to meet the US Department of Energy’s electric vehicle pack goals for weight, energy density, and cost by 2022. Meanwhile, building cells with lithium metal electrodes could increase the energy density of the same batteries by as much as 50 percent.

Last week, researchers from Yale University published a paper in the scientific journal Proceedings of the National Academy of Sciences that detailed a new approach to working with lithium metal electrodes. Hailaing Wang, the lead researcher, described it as “aggressively trying to use 80 to 90 percent of the lithium” in a battery, otherwise known as deep-cycling. Before the batteries were assembled, the researchers immersed a glass fiber separator in a lithium nitrate solution. Then, while the batteries were operating, the slow release of that lithium nitrate and its decomposition were found to “greatly improve the performance of lithium metal electrodes.”

But the biggest problem with lithium metal is that it still makes for extremely volatile batteries that generate a lot of heat. Wang and his team were able to successfully demonstrate that this combination of technology–lithium metal plus protective additives–works in the lab. Real-world use is a different matter. “We were operating at a low scale, and the conditions were well controlled, so safety was not a concern,” Wang said over the phone. He described it as “good progress, but still far from being commercialized.”

Solid State

Battery wonks sometimes use “solid state” and “lithium metal” interchangeably, since they can apply to different parts of a battery and co-exist within the same battery structure. And, like lithium metal, solid state batteries have gotten an increasing amount of attention in recent years because of their potential use in EVs. A solid state battery is one that replaces either the battery’s electrodes, its liquid electrolyte, or both, with some type of solid like ceramic or glass. Because you’re replacing the highly flammable materials (aren’t you glad you were paying attention at the start of class?) with something solid, the idea is that the battery can withstand higher temperatures, which in theory means higher capacity.

One Woburn, Massachusetts-based company is taking a slightly different approach. Ionic Materials is replacing the liquid electrolyte with an ionically-conductive polymer, or plastic, that’s also a fire retardant material.

“People are working on variations of anodes and cathodes, but the real block [to battery advancement] is the electrolyte, which is what we’re trying to improve upon,” says Mike Zimmerman, CEO of Ionic Materials. He noted that ceramic and glass can be brittle, and can give off gases when exposed to moisture, so he believes those solids are less-than-ideal solutions for solid state batteries. One of Ionic Materials’s key investors told WIRED’s Steven Levy last year that the company is trying to combine the best aspects of the low-cost alkaline batteries with power and rechargeable nature of lithium ion. If the company can crack that formula, it believes it can even power an entire smart grid with its technology.

Again, that doesn’t mean solid state batteries will flood the market anytime soon. Last year Toyota admitted it was having issues developing high-capacity solid state batteries. Then, in April, a senior vice president of research and engineering at Nissan said that development of solid state batteries is “practically a zero at this stage.”

But one other move may give Ionic Materials an advantage: it says it doesn’t plan to do its own manufacturing, but instead wants to license its technology to existing battery makers. For most innovators in battery tech, even if they solve the problems of materials, chemistry, and safety, building a facility to produce batteries at scale is a tremendous challenge. It turns out that, unless you have the leverage of Elon Musk, you can’t just build your own giant Tesla Gigafactory.


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