While that’s low enough to have triggered quickening adoption of electric vehicles, even the cheapest lithium-ion chemistries are still too expensive to put a big battery in every home to protect against blackouts. “When produced at the same scale, sodium-ion should be about half of where lithium-iron-phosphate is in terms of cost to produce because the raw materials are a hundred times cheaper,” Darren Tan, co-founder and CEO of Unigrid, told TechCrunch. Tan’s startup thinks it has solved those problems by using a new chemistry based on sodium-chromium-oxide in one half of the battery and tin in the other (though Tan emphasizes the company can substitute other materials on either side).