Electrochemical performance of layered Li[Li0.15Ni0.275–xMgxMn0.575]O2 cathode materials for lithium secondary batteries

Abstract

The Li[Li_0.15Ni_0.275−xMg_xMn_0.575]O₂ (x = 0, 0.02, and 0.04) powders have been synthesized using a sol–gel method. The layered structure of the materials is stabilized by a small amount of Mg substitution for Ni. The structural stability and cycling behavior are improved by an increase in the Mg content. The XAS measurements show that charge compensation by delithiation could be achieved by the oxidation of the oxygen ion as well as by the oxidation of Ni²⁺ to Ni³⁺, while maintaining the Mn atoms in the 4+ oxidation state.