BATTERY, BATTERY PACK, ELECTRONIC DEVICE, ELECTRICALLY-POWERED VEHICLE, POWER STORAGE DEVICE AND ELECTRIC POWER SYSTEM

PROBLEM TO BE SOLVED: To suppress decomposition of an electrolyte near a positive electrode under a high temperature environment.SOLUTION: A battery comprises a positive electrode and an electrolyte, and a phosphorus compound having a P-OH structure is added to at least one of the positive electrode and the electrolyte. As a result of the addition of the phosphorus compound, a protective coating film containing, as a main component, at least one of phosphate derived from the phosphorus compound having the P-OH structure and a metal salt of its derivative is formed on the surface of at least one of the positive electrode and a positive electrode active material as the battery is charged and discharged. The addition of the phosphorus compound having the P-OH structure is particularly effective in a battery which contains, as a negative electrode active material, a lithium transition metal compound having a Spinel structure. The electrolyte is preferably held by a polymer material, thereby making an illiquid electrolyte. This electrolyte is particularly effective in application to a battery having positive and negative electrodes and an electrolyte sheathed by a laminate film.