Patent ID: 7527896

Claim:
A nonaqueous electrolyte secondary battery which comprises a positive electrode including particles of lithium-containing layered nickel oxide represented by a general formula Li a Ni x Co y Al z M b O 2 , wherein: 0.3≦a≦1.05, 0.7≦x≦0.87, 0.1≦y≦0.27, 0.03≦z≦0.1, 0≦b≦0.1; M is at least one selected from metallic elements except Ni, Co and Al, and in binding energy of oxygen 1s spectrum when measuring said particles by XPS, if a peak area appearing at 529 eV is set to D; a peak area appearing at 531 eV is set to E; oxygen concentration ratio is set to D/(D+E); and oxygen concentration ratios at depths of L1 nm and L2 nm from the particle surface are respectively set to α L1 and α L2 , a combination of L1 and L2 in which (α L2 −α L1 )/α L2 ≦0.1, L1≦100, L2≧500 is present.