Described here is a rechargeable battery comprising (a) an electrode comprising manganese hexacyanomanganate in contact with (b) an electrolyte comprising sodium and/or potassium ions. Also described here is a method for making a sodium-ion rechargeable battery, comprising incorporating manganese hexacyanomanganate into an electrode, and contacting said electrode with an electrolyte comprising sodium ions or potassium ions.
FEDERAL FUNDING STATEMENT
 This invention was made with Government support under Contract No. DEA C05-76RL01830, awarded by U.S. Department of Energy. The Government has certain rights in the invention.