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After Decades of Explosions, Battery Startups Give the Green Light to Liquid and Lithium-Metal
Cuberg says it’s all in how you make your electrolyte
Forecasts of a revolution in batteries — ushering in much cheaper electric vehicles with far greater range — have rested largely on the promise of a coming technological breakthrough: an electrode made of pure lithium metal, delivering much more energy than current lithium-ion. The prognostications have even foreshadowed what that leap would look like: Since lithium is exceedingly reactive and can explode when in contact with liquid, the much-sought battery would feature a “solid-state” separator that allows ions to shuttle quickly while preventing the two electrodes from shorting out.
But two big announcements this week suggest that the decadeslong quest for a magical solid-state battery material may have been unnecessary. A liquid electrolyte, both suggested, works just fine with lithium metal.
What makes lithium-metal seductive to battery-makers is the energy it produces while weighing relatively little. Lithium-metal can pack in about 50% more energy than lithium-ion in the same space, allowing automakers to charge much less for electric vehicles (EVs) than they currently do.
Work on such batteries began in the 1970s but with disastrous results. Researchers favored liquid as the electrolyte — the part of the battery lying between the two electrodes — because ions move quickly through it. In an EV, fast-moving ions equate to rapid acceleration. In addition, virtually all current EV battery systems use a liquid electrolyte so that a lithium-metal battery using liquid can be manufactured using the same factory equipment. But the explosions created a mindset that, if you were thinking lithium-metal, you had to exclude liquid, and today’s best-known lithium-metal companies — such as QuantumScape and Solid Power — use solid separators.
But in an interview yesterday on Washington Post Live, GM president Mark Reuss said that the Detroit giant would build a pilot manufacturing plant with SES, a Massachusetts-based developer of a liquid-based lithium-metal battery. Reuss said the plant, to be finished by 2023, will manufacture battery prototypes.
