Win-win solid-state battery discovery
Metal Tech News - November 11, 2022
Last updated 11/14/2022 at 11:51am
Energy-dense, stable ceramic lithium battery electrolyte offers new use for a plentiful rare earth element.
In what could be a win-win discovery for the future of long-range electric vehicles and the rare earths mining sector, engineers at California-based American Elements have invented a ceramic electrolyte material for use in solid-state lithium-sulfur batteries.
Lithium-sulfur batteries can store somewhere between two and five times as much energy by weight than the current generation of lithium-ion batteries. For auto manufacturers and consumers, this would translate to a car that could travel 600 to 1,500 miles on a single charge with a battery roughly the same weight that is being installed in the EVs currently rolling off assembly lines.
Put another way; a person could travel eight to 20 hours at a highway cruising speed of 75 miles per hour before needing to plug in. Even at the low end, this is further than most want to travel in a day.
At the very least, a one-hour recharge of the batteries in both the EV and driver is likely warranted after a trek equivalent to traveling from New York to Florida (about 900 miles).
These range-anxiety-eliminating lithium-sulfur batteries, however, have some drawbacks that need to be overcome before they are ready for commercial use.
Solid ceramic solutions
The main problem that must be resolved before lithium-sulfur batteries are ready for a test drive on global highways is that every time you charge them, little tree-like structures called dendrites sprout up and grow on the anode (negative electrode) side of the battery. As these troublesome dendrites branch out, they degrade the anode and electrolyte and eventually short out the battery entirely.
Pulsedeon, a battery materials sciences company out of Finland, has developed a solution that uses lasers to deposit a thin ceramic composite layer that prevents the growth of these unruly dendrite spikes.
The other issue is that while lithium-sulfur batteries can store more electricity per pound, they tend to be larger. To keep the size as small as possible, scientists are looking into ceramic electrolytes – this is where the American Elements discovery comes into play.
The electrolyte developed by engineers in the material science center of this Los Angeles-based purveyor of advanced materials is a ceramic compound made with lithium, lanthanum, and zirconium oxide nanoparticles. American Elements says this solid sulfur-lithium battery electrolyte is energy-dense and stable in a wider range of temperatures than typical liquid electrolytes used in today's commercial lithium-ion batteries.
It is the liquid electrolytes that are the main culprit of headline-grabbing lithium-ion battery fires in EVs and electronic devices.
"With this significant invention, American Elements is demonstrating its commitment to fostering innovations in efficient energy storage technologies that help address performance and safety concerns about the current generation of lithium-ion batteries," said American Elements Chairman and CEO Michael Silver.
Overabundant rare earth
How does this solid-state ceramic battery improvement technology help the rare earths mining sector?
The obvious answer is lanthanum is a rare earth element, but it goes beyond that.
While often talked about as one commodity, rare earths are, in reality, a group of 15 elements – each with its own unique characteristics.
"There are literally hundreds of uses for rare earths – they are unique materials, almost alchemistical magic," Silver said during a 2011 critical minerals conference in Alaska.
While each of these seemingly magical elements has its own unique characteristics and uses, they are always found together in nature. So, all rare earth mines produce some mix of all the rare earths – except for promethium, which is truly rare – some of which are in high demand and others are not.
In a world transitioning to EVs and renewable energy, automakers and wind energy manufacturers are placing especially high demands on the magnetic rare earths – mainly neodymium, praseodymium, dysprosium, and terbium. Producing the needed volumes of these rare earths that help make EV motors and wind turbine generators more efficient means that there is an abundance of other rare earths, such as lanthanum, stacking up at mines and processing facilities around the world.
Because of this, 99.9% pure lanthanum oxide sells for only about $1.25 per kilogram, while similar grade neodymium oxide sells for around $180/kg, praseodymium oxide for $175/kg, dysprosium oxide for $560/kg, and terbium oxide for $3,560/kg.
A little bit of the low-cost lanthanum going into future solid-state lithium batteries that deliver power to EV motors enhanced with the much higher-priced magnet rare earths could help bring some balance to the market.
This makes the ceramic electrolyte developed by the material scientists at American Elements a win-win that provides a new market for the lanthanum piling up at mines trying to keep up with magnet rare earth demand, while also offering an inexpensive ingredient for ceramic electrolytes that may someday allow EV drivers to travel nearly halfway across the United States on a single charge.