Tesla Motors shared some interesting chemical plans at its recent “battery day,” including cutting steps from its production process and cobalt from its cathodes. Company executives also discussed anodes made from silicon embedded in conductive polymers. It looks as if they’re sticking with liquid electrolytes, though, despite the risk they bring from flammability and dendrite formation.
Developers of solid-state batteries are betting that Tesla will rethink that stance as their products move out of the lab and onto the manufacturing line. Last week, Solid Power shipped 250 prototype battery cells that use its solid sulfide–based electrolyte. The firm’s partners will test performance of the cells and see how well they stand up to abuse.
Though the prototypes aren’t suitable for automotive use, that’s clearly what Solid Power is aiming for. The company, one of C&EN’s 10 Start-Ups to Watch in 2017, now has investments or partnerships with Ford, BMW, Hyundai, and the auto-parts maker Sanoh Industrial. It says its production line uses much of the same equipment that lines for established lithium-ion batteries do.
Christopher Robinson, a senior analyst at Lux Research, says announcements like Solid Power’s are promising. “We expect solid-state batteries to be used in production vehicles in 5–10 years,” he says. “The belief is that a solid electrolyte will enable a type of anode—specifically metallic lithium—which is significantly more energy dense than today’s.”
Last month, the solid-state battery firm QuantumScape announced a deal to go public with a $3.3 billion valuation. The firm’s batteries use lithium-metal anodes, which CEO Jagdeep Singh has said could give electric vehicles ranges of up to 500 miles. QuantumScape has financial backing from Bill Gates and a development agreement with Volkswagen.
Another player in solid electrolytes is Ionic Materials, which has a partnership with Li-ion battery maker A123 Systems. The two repurposed an A123 plant in Michigan to make prototype cells based on Ionic’s solid polymer electrolyte.
Battery watchers should be patient though, Robinson says. “Development is still ongoing, and solid-state batteries which tick all the boxes on an automaker’s spec sheet don’t exist today.”