Enhanced cyclic performance of O2-type Mn-based layered oxide via Al doping for lithium-ion battery

The layered lithium nickel manganese oxide Li _yNi _xMn _1−xO ₂ cathode materials with O2 structure exhibit good cyclic stability owing to their special arrangement of oxygen layers. However, the O2-type oxides generally present limited discharge capacity because of Li ⁺ ions defects in the lithium layer (as in Li _yNi _xMn _1−xO ₂ , y < 1). Herein, an O2-type layered lithium nickel manganese oxide LiNi _0.33Mn _0.65Al _0.02O ₂ with high capacity and good capacity retention is obtained by introducing lithium and aluminum into the transition metal layer. The results of structural characterization and performance tests show that the optimal amount of Li ⁺ and Al ³⁺ in the transition metal layer effectively inhibits the disordered migration of transition metal ions and increases the electrochemical stability. The LiNi _0.33Mn _0.65Al _0.02O ₂ cathode delivers an initial discharge capacity of 153 mAh g ⁻¹ and the capacity only attenuates 13% after 100 cycles at the current density of 200 mA g ⁻¹, which are higher than that of undoped oxide LiNi _0.33Mn _0.67O ₂.