Alternative chemistries, such as lithium iron phosphate deployed by some carmakers including Toyota, have tradeoffs and aren’t necessarily wholesale substitutes for lithium ion, Pratt said.
Sodium-based chemistries, for example, have lower energy densities because the sodium molecule is bigger than the lithium molecule. Sodium batteries might be put to better use in stationary power packs, whereas lithium ion ones might continue having more merit in vehicles.
“Lithium ion is here for quite some time because it’s so good,” Pratt said. “We’re really unlikely to find something that’s dramatically better on multiple axes in the near future.”
Toyota plans to plow nearly $14 billion into battery development through 2030, including plans for a ramp-up of solid-state batteries and next-generation lithium ion power packs.
Reliance on lithium is a big reason Toyota Motor Corp. continues to plug hybrid vehicles as a potent path to reducing global carbon dioxide emissions. Spreading limited resources of lithium across a larger fleet of hybrids takes a bigger bite out of emissions than concentrating the lithium in a smaller number of full-electric vehicles, according to Toyota’s calculations.
The impact will be especially acute over the next decade or so because the global supply of lithium is expected to be constrained as new lithium mines and processing centers are set up.
“Our hope is that the supply shortages can be resolved roughly 20 years from now,” Pratt said.
Recycled lithium coming back to market from batteries in older EVs and hybrids taken out of circulation should ease the bottleneck.
Solid-state batteries offer one avenue to more efficient use of lithium. Pratt said solid-state requires about half the lithium of today’s liquid-electrolyte lithium ion batteries.
But those batteries are several years away and may take even longer to go mainstream.
