Lithium-ion batteries store energy by insertion (“intercalation”) of singly charged lithium ions (Li+) in a graphite anode, and release energy by transferring these ions through an electrolyte to a lower energy state in a metal oxide or metal phosphate cathode. Replacing the lithium ions with ions having two or three positive charges (“multivalent”) could increase the battery energy storage capacity by a factor of two or three. When JCESR began in 2012, only one combination of anode, electrolyte, cathode, and multiply charged working ion had been discovered, illustrating the difficulty of the challenge.
In the first half of its five-year charter, JCESR conducted a computer-driven screening of 1,800 candidate multivalent host structures, the largest such systematic survey ever undertaken. This effort identified the most promising ions as calcium and magnesium, both of which have a two-plus charge (Ca2+ and Mg2+). Additionally, Electrolyte Genome calculations identified correlations between molecular level interactions and key electrolyte properties. This information advances the design of optimal electrolytes for magnesium batteries.
“Modern society is completely dependent on fossil fuels, so there’s a huge incentive to find a replacement for the internal combustion engine. We have to find a way to liberate society from that dependence. What we’re talking about is to be able to get electric energy from sun and wind, instead of from coal. But that’s not feasible unless you have storage.”
– John Goodenough, the father of today’s lithium-ion batteries.