[floatrock]

CATL is kinda doing that for EVs. They're making battery packs that are a blend of sodium-ion and lithium-ion.

Sodium-ion isn't as energy dense as lithium-ion and it has a slightly smaller power efficiency, but it's a lot cheaper, has better cold resistance, and can deliver more power at low states of charge.

Use the two together and the thinking is you can get a sweet spot that performs better across a wider range of conditions your cars are likely to experience.