SODIUM SECONDARY BATTERY

摘要

Provided is a long-lasting sodium secondary battery, said battery being a molten-salt battery using sodium or a sodium compound as an active material, that excels in terms of non-flammability and safety. Said sodium secondary battery is characterized by having a positive electrode, a negative electrode, an electrolyte disposed therebetween, and a separator that separates the positive and negative electrodes from each other and is immersed in the electrolyte. This sodium secondary battery is also characterized in that: the positive electrode and/or the negative electrode contains sodium or a sodium compound as an active material; the electrolyte is a molten salt containing anions that can be represented by (RSO2)2N− (each of the two Rs independently representing either a fluorine atom or a fluoroalkyl group) and at least one type of metal cation selected from among the alkali metals and the alkaline earth metals; and the separator comprises an organic material that contains at least one element selected from the group consisting of sulfur, chlorine, bromine, iodine, and nitrogen but contains no N-O bonds or C-F bonds.