As demand for electric vehicles and grid storage surges, battery makers are searching for alternatives to lithium that are cheaper and easier to source. New research suggests sodium-ion batteries, which have long been heralded as a promising alternative, may be maturing faster than expected. Lithium-ion batteries dominate the market thanks to their excellent energy density and well-developed supply chains. But lithium prices have been swinging wildly in recent years, and there are concerns about lithium market concentration—the vast majority of extraction happens in a handful of countries, like Australia and Chile, and China dominates lithium processing. This has driven interest in novel chemistries. Sodium is a leading contender due its low price and abundant deposits all over the globe, but performance concerns have held back adoption. Chinese companies, however, have begun to take sodium batteries seriously.…