“Most of these developments are not really due to fundamental improvements in chemistry,” says Mauro Pasta, an applied electrochemist at the University of Oxford. “What has changed the game is the economies of scale in manufacturing.”
Liu points to a good example: the roll-to-roll process used for the cylindrical batteries found in most of today's electric cars. “You make a slurry,” says Liu, “then you pour the slurry into thin films, roll the films together at very high speed and precision, and you can very, very quickly make hundreds and thousands of cells with very high quality.”
Lithium-ion cells have also made great strides in safety. The existence of this flammable electrolyte means that EV accidents can lead to difficult-to-extinguish lithium-ion fires. But thanks to the circuit breakers and other protections built into modern battery packs, only about 25 of 100,000 electric cars sold catch fire, compared to about 1,500 fires per 100,000 conventional cars – which, of course, carry large tanks of explosively flammable gasoline.
In fact, McCalla says, the standard lithium-ion industry is so far ahead that solid-state technology may never catch up. “EVs will scale up today,” he says, “and they will go with the technology that is affordable today.” Battery manufacturers are increasing their lithium-ion capacity as quickly as they can. “So I wonder if the train has left the station yet.”
But maybe not. Solid-state technology does indeed have geopolitical appeal, notes Ying Shirley Meng, a materials scientist at the University of Chicago and Argonne National Laboratory. “With lithium-ion batteries, it's game over: China already dominates 70 percent of production,” she says. So for any country looking to lead the next battery revolution, “solid-state presents a very exciting opportunity.”
Performance potential
Another plus is improved performance. Just as EV buyers are looking for ever-increasing range and charging speed, Louli says, the standard lithium-ion recipe is reaching a performance plateau. To do better, he says, “you have to go back and do some material innovations” – like those in solid-state batteries.
