TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The rare earth oxide is oxide of yttrium, lanthanum, cerium, promethium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, ytterbium and/or lutetium. The content of rare earth oxide is 0.005-10 atomic%, with respect to total amount of manganese, nickel and cobalt. The rare earth oxide is given by formula: RE2O3 and composite material which consists of lithium, nickel, manganese and cobalt is given by formula: LixNiaMnbCocO2, where RE is trivalent rare earth elements, x is greater than 0 and less than 1.2, a, b, c are greater than 0 and less than 1, and a+b+c=1. Rare earth oxide microparticle(s) (2) exists in grain boundary and/or surface of primary complex oxide particles (1) which contain lithium, nickel, manganese and cobalt.Preferred Properties: The primary complex oxide particles have average particle diameter of 0.1-2 microns. The rare earth oxide microparticles have average particle diameter of 0.01-0.5 microns. The average particle diameter of secondary particles contained in primary complex oxide particles and rare earth oxide microparticles is 1-15 microns.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The rare earth oxide is oxide of yttrium, lanthanum, cerium, promethium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, ytterbium and/or lutetium. The content of rare earth oxide is 0.005-10 atomic%, with respect to total amount of manganese, nickel and cobalt. The rare earth oxide is given by formula: RE2O3 and composite material which consists of lithium, nickel, manganese and cobalt is given by formula: LixNiaMnbCocO2, where RE is trivalent rare earth elements, x is greater than 0 and less than 1.2, a, b, c are greater than 0 and less than 1, and a+b+c=1. Rare earth oxide microparticle(s) (2) exists in grain boundary and/or surface of primary complex oxide particles (1) which contain lithium, nickel, manganese and cobalt.Preferred Properties: The primary complex oxide particles have average particle diameter of 0.1-2 microns. The rare earth oxide microparticles have average particle diameter of 0.01-0.5 microns. The average particle diameter of secondary particles contained in primary complex oxide particles and rare earth oxide microparticles is 1-15 microns. EXAMPLE - Lanthanum oxide (La2O3) powder was added to complex oxide (Li1.02Ni0.60Mn0.20Co0.30O2) obtained by baking a raw material mixture having Li2CO3, MnO2 and CoCO3 at 1025degreesC for 10 hours. The obtained mixture was baked at 925degreesC for 10 hours, and anode material was obtained. The average particle diameter of primary particle of complex oxide was 0.5 microns and average particle diameter of rare earth oxide particle was 0.03 microns. The battery produced using the obtained anode material had high safety, output characteristics, durability and high energy density.