Fighting Has Broken Out Over How Long Lithium Metal Can Sit on the Shelf
A new paper has claimed up to a 25% capacity loss
For years, they were the Don Quixotes of the battery world — tinkerers in pure lithium metal romantically seeking to install them in batteries, only to find them catching fire and the answers they thought would fix them a mirage. Then, over the last six months, these People of La Mancha became the toast of Silicon Valley and Wall Street, winning high-dollar valuations in SPAC deals and courted by virtually every major automaker in the world.
Now, a new paper published Monday at Nature Energy has triggered a heated debate in the battery community, asserting that in certain cases, lithium-metal batteries suffer a catastrophic loss of lifetime capacity. The issue is calendar life — how many years a battery can be useful, regardless of whether the vehicle in which it’s installed is driven or not. The paper, written by nine authors at Stanford University led by Yi Cui, a materials scientist, found that in extreme testing, lithium-metal batteries lose up to 25% of their lifetime capacity just sitting around.
Major automakers including General Motors and Volkswagen are relying on pure lithium-metal batteries to make next-generation electric vehicles ultra-affordable and allow them to crack the mass market. But the paper waves a gigantic red flag, suggesting that researchers need to heed this potential flaw in order to ensure that lithium-metal batteries work for a full guaranteed lifetime. “If you lose 25%, it’s game over,” said Venkat Viswanathan, a professor at Carnegie Mellon. “At 20%, you already lose the useful life of the battery.”
On Twitter, where battery debate has gravitated in recent months, some researchers heavily criticized the paper. The primary assertions are that the test was carried out under excessively adverse conditions and that the protocol didn’t actually test calendar life. A third claim was that the result was highly dependent on what type of electrolyte and cell format were used.
Cui, the paper’s primary author, declined to respond to emailed questions.
Among those to hotly challenge the paper was Shirley Meng, a materials science professor at the University of California, San…