Abstract: A positive electrode active material for a lithium ion secondary battery is lithium vanadium phosphate represented by a following composition expression (1) and in which a peak intensity ((002)int/(201)int) of a (002) plane normalized with respect to a peak intensity of a (201) plane and a peak intensity ((102)int/(201)int) of a (102) plane normalized with respect to a peak intensity of the (201) plane in an X-ray diffraction pattern satisfy 0.35?(002)int/(201)int?0.53 and 0.46?(102)int/(201)int?0.63, respectively, LixVOPO4 . . . (1).

Abstract: A positive electrode active material for lithium ion secondary battery includes: active material particles including one or more compounds including Li and a transition metal; and a coating layer coating at least a part of a surface of the active material particles. The coating layer includes at least one of graphene or multilayer graphene The coating layer has a Raman spectrum with a G band (a peak of 1530 cm?1 to 1630 cm?1), a D band (a peak of 1300 cm?1 to 1400 cm?1), and a 2D band (a peak of 2650 cm?1 to 2750 cm?1). At least the intensity of the 2D band normalized by the intensity of the G band (2Dint/Gint) satisfies 0.05?2Dint/Gint.

Abstract: A positive electrode active material for a lithium ion secondary battery is lithium vanadium phosphate represented by a following composition expression (1) and in which a peak intensity ((002)int/(201)int) of a (002) plane normalized with respect to a peak intensity of a (201) plane and a peak intensity ((102)int/(201)int) of a (102) plane normalized with respect to a peak intensity of the (201) plane in an X-ray diffraction pattern satisfy 0.35?(002)int/(201)int?0.53 and 0.46?(102)int/(201)int?0.63, respectively, LixVOPO4??(1).

Abstract: A positive electrode active material for lithium ion secondary battery, includes: a lithium nickel complex oxide represented by composition formula (1); a phosphate compound; and a coating layer formed on at least a part of a surface of a particle of the lithium nickel complex oxide, and including a high thermal conductive material with heat conductivity of 500 W/m·K or more. The coating layer of the particle of the lithium nickel complex oxide includes a portion connected to the coating layer of another particle of the lithium nickel complex oxide: LixNi1-yMyO2??(1) where M includes at least one metal selected from the group consisting of Co, Fe, Ti, Cr, Mg, Al, Cu, Ga, Mn, Zn, Sn, B, V, Ca, and Sr, and x and y are such that 0.05?x?1.2 and 0?y?0.5.

Abstract: A positive electrode active material for lithium ion secondary battery includes: active material particles including one or more compounds including Li and a transition metal; and a coating layer coating at least a part of a surface of the active material particles. The coating layer includes at least one of graphene or multilayer graphene The coating layer has a Raman spectrum with a G band (a peak of 1530 cm?1 to 1630 cm?1), a D band (a peak of 1300 cm?1 to 1400 cm?1), and a 2D band (a peak of 2650 cm?1 to 2750 cm?1). At least the intensity of the 2D band normalized by the intensity of the G band (2Dint/Gint) satisfies 0.05?2Dint/Gint.