MANUFACTURING METHOD FOR POSITIVE ELECTRODE ACTIVE MATERIAL FOR POWER STORAGE DEVICE

PROBLEM TO BE SOLVED: To provide a manufacturing method for a positive electrode active material for a power storage device, whose capacity characteristic and electron conductivity are improved.SOLUTION: A manufacturing process for a positive electrode active material for a power storage device containing a lithium silicate compound represented by the general formula LiMSiOcomprises high-temperature heat treatment on a mixture material, comminution treatment, addition of a carbon-based material, and then another heat treatment. The reactivity between the substances included in the mixture material can be increased and the crystallinity can be improved. At the same time, carbon can be held on a particle surface of the crystallized mixture material while the crystal grain size, which has been expanded in the high-temperature heat treatment, is reduced and the crystallinity is recovered. This can facilitate the insertion/deinsertion of lithium for the obtained positive electrode active material and allows the manufacture of the positive electrode active material for a power storage device with higher electron conductivity. Further, by manufacturing a lithium ion secondary battery with the obtained positive electrode active material for a power storage device, a lithium ion secondary battery with high discharge capacity can be obtained.