Synthesis and electrochemical performance of lithium-rich cathode material

Lithium-rich cathode material Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ has been synthesized by sol-gel method followed by a high-temperature calcination process at 800℃ and 900℃ (signed as S8 and S9, respectively). The structure, morphology and electrochemical properties of as-synthesized materials are characterized in detail. Electrochemical test results show that sample S9 has higher discharge capacity, better cyclic stability and smaller charge transfer resistance. Sample S9 delivers the initial charge capacity of 345.0 mA·h·g^-1 and the initial discharge capacity of 273.9 mA·h·g^-1 at 0.1C (25 mA·g^-1) with a coulombic efficiency of 79.4%. The discharge capacity is 173.3 mA·h·g^-1 at 1 C after 30 cycles, remaining 92.1% of initial discharge capacity (188.1 mA·h·g^-1). The results indicate that the ordering between lithium and transition metal cations in their respective layers needs a higher calcination temperature in spite of the formation of the R-3m layered phase at 800℃. It is helpful to effectively improve the electrochemical properties.