This solid-state battery technology is still years away from going commercial—Solid Power plans to ramp up to producing enough material for 800,000 cars annually by 2028—but if it proves practical, the batteries could increase the performance of electric vehicles significantly.
Solid Power won’t be making and selling full batteries in the future, however. Instead, it will provide the solid electrolyte material to other battery makers, says CEO Doug Campbell.
The electrolyte shuttles charge around inside a battery as it’s charging or releasing power. In lithium-ion batteries that power electric vehicles today, the electrolyte is liquid; solid-state batteries use a solid layer of electrolyte that’s squished between the other layers of the battery to ferry charge.
The approach unlocks new options for battery chemistry. In particular, lithium metal and silicon-based chemistries are unstable or unsafe when combined with liquid electrolyte in the cell, but could be used in theory if a solid were swapped in instead.
The result would be a battery that could pack more energy into a smaller space—meaning cars could go farther before running out of charge. Solid Power’s batteries could eventually improve the energy density of lithium ion batteries by about half, Campbell says, so a vehicle that used to go 350 miles before needing to be recharged might be able to stretch its range above 500 miles.
Ditching the liquid would also make it easier to build safer cells, Campbell adds. While lithium-ion batteries have been engineered with protections to make sure they don’t catch fire or explode, removing the liquid would in turn remove the need for these costly additions. Battery packs, which are made up of many cells together, could be denser, because their internal temperature controls and safety systems would require less space.
The concept of taking liquid electrolytes out of battery cells isn’t new, says Lei Cheng, a chemist and battery researcher in the materials division at Argonne National Laboratory. For years, though, much of the research on solid batteries has been focused on using organic polymers, like polyethylene oxide.