Patent ID: 7879494
Filing Date: 2011-02-01
Classification: H01M,Y02E,Y10T

Abstract:
1. A lithium ion secondary battery comprising a positive electrode capable of charging and discharging, a negative electrode capable of charging and discharging, and a non-aqueous electrolyte; said positive electrode including active material particles; said active material particles including at least a first lithium-nickel composite oxide forming a core portion thereof; said first lithium-nickel composite oxide being represented by Li where 0.85≦x≦1.25, 0<y≦0.5, 0≦z≦0.5, 0<y+z≦0.75, and element Me is at least one selected from the group consisting of Al, Mn, Ti, Mg, and Ca; a surface layer portion of said active material particles including: (i) at least one selected from the group consisting of a nickel oxide having a NaCl crystal structure and a second lithium-nickel composite oxide including a domain having the NaCl crystal structure; and (ii) element M not incorporated in the crystal structure of said first lithium-nickel composite oxide, said element M being at least one selected from the group consisting of Al, Mn, Mg, B, Zr, W, Nb, Ta, In, Mo, and Sn.