Optimized Synthetic Conditions of 0.6Li2MnO3·0.4LiNi1/3Co1/3Mn1/3O2 Cathode Materials for Lithium Batteries via Sol-Gel Method

Li-rich layer-structure 0.6Li2MnO3·0.4LiNi1/3Co1/3Mn1/3O2 (LMO) cathode materials have been synthesized by sol-gel method using citric acid as a cheating agent. The effects of different ratios of solvent and the amount of excessive lithium are discussed systematically. When changing the ratio of ethanol/H2O and the amount of excessive lithium, the morphology and electrochemical properties will be changed accordingly. The crystal structure of Li-rich LMO was characterized by X-ray diffraction. The morphology was characterized by scanning electron microscope, and the Li-rich LMO cathodes show bulk with the particle size of around 150 nm. The charge/discharge test showed the Li-rich LMO synthesized with 100% ethanol and 5% Li excess sintered at 900 °C for 24 h subsequently has the best electrochemical performance. Within the cut-off voltage between 2.5 and 4.8 V, the initial discharge capacity is 256.8 mAh g-1 at 0.1 C; and after 50 cycles the discharge capacity remains 230.2 mAh g-1. By modifying the ratio of solvent in the formation of gel, it is promising to extend the synthesis of other electrode materials of lithium ion batteries basing on the traditional sol-gel method.