Mobile technology is increasing in power exponentially, but battery tech isn’t keeping up. We’re reaching the physical limits of what conventional lithium-ion and lithium-polymer designs can do. The solution might be something called a solid-state battery.
What’s A Solid-State Battery?
In a conventional battery design—most commonly lithium-ion—two solid metal electrodes are used with a liquid lithium salt acting as an electrolyte. Ionic particles move from one electrode (the cathode) to the other (the anode) as the battery charges, and in reverse as it discharges. The liquid lithium salt electrolyte is the medium that allows that movement. If you’ve ever seen a battery corrode or get punctured, the “battery acid” that oozes (or sometimes explodes) out is the liquid electrolyte.
In a solid-state battery, both the positive and negative electrodes and the electrolyte between them are solid pieces of metal, alloy, or some other synthetic material. The term “solid-state” might remind you of SSD data drives, and that’s not a coincidence. Solid-state storage drives use flash memory, which doesn’t move, as opposed to a standard hard drive, which stores data on a spinning magnetic disc powered by a tiny motor.
Though the idea of solid-state batteries has been around for decades, advances in their development are just beginning, currently spurred on by investment from electronics companies, car makers, and general industrial providers.
What’s Better About Solid-State Batteries?
Solid-state batteries promise a few distinct advantages over their liquid-filled cousins: better battery life, faster charging times, and a safer experience.
Solid-state batteries compress the anode, cathode, and electrolyte into three flat layers instead of suspending the electrodes in a liquid electrolyte. That means you can make them smaller—or at least, flatter—while holding as much energy as a larger liquid-based battery. So, if you replaced the lithium-ion or lithium-polymer battery in your phone or laptop with a solid-state battery the same size, it would get a much longer charge. Alternatively, you can make a device that holds the same charge much smaller or thinner.
Solid-state batteries are also safer, since there’s no toxic, flammable liquid to spill, and they don’t output as much heat as conventional rechargeable batteries. When applied to batteries that power current electronics or even electric cars, they might recharge much faster, too—ions could move much more quickly from the cathode to the anode.
According to the latest research, a solid-state battery could outperform conventional rechargeable batteries by 500% or more in terms of capacity, and charge up in a tenth of the time.
What Are the Disadvantages?
Because solid-state batteries are an emerging technology, they’re incredibly expensive to manufacture. So expensive, in fact, that they aren’t installed in any major consumer-grade electronics at the time of writing. In 2012, analysts writing for the University of Florida Software Analysis and Advanced Materials Processing department estimated that a typical cell phone-sized solid-state battery would cost about $15,000 to manufacture. One big enough to power an electric car would cost $100,000.
Part of this is because the economies of scale aren’t in place—hundreds of millions of rechargeable batteries are made each year right now, so the manufacturing cost of the materials and equipment are spread out across huge supply lines. There are only a few companies and universities researching solid-state batteries, so the cost to produce each one is astronomical.
Another issue is the materials. While the properties of various metals, alloys, and metallic salts used for conventional rechargeable batteries is well-known, we don’t currently know the best chemical and atomic composition for a solid electrolyte between metallic anodes and cathodes. Current research is narrowing this down, but we need to gather more reliable data before we can gather or synthesize the materials and invest in manufacturing processes.
When Will I Get to Use a Solid-State Battery?
As with all emerging technology, trying to figure out when you’ll get your hands on it is guesswork at best.
It’s encouraging that many enormous corporations are investing in the research needed to bring solid-state batteries into the consumer market, but shy of a major breakthrough in the immediate future, it’s hard to say whether there will be a great leap forward. At least one car company says it will be ready to put one in a vehicle by 2023, but doesn’t guess how much that car might cost. Five years seems overly optimistic; ten years seems more likely. It might be twenty years or more before the materials are settled upon and the manufacturing processes are developed.
But as we said at the beginning of the article, conventional battery tech is starting to hit a wall. And there’s nothing like potential sales to spur on research and development. It’s at least slightly (very, very slightly) possible that you might be able to use a gadget or drive a car powered by a solid-state battery soon.