Synthesis of lithium nickel cobalt manganese oxide cathode materials by infrared induction heating

摘要

This study adopts an in-situ infrared (IR) sintering incorporated with carbonization technique to synthesize carbon-coated LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 (LNCM) cathode materials for Li-ion batteries. Compared with electric resistance heating, the in-situ IR sintering is capable of rapidly producing highly-crystalline LNCM powders at 900 ℃ within a short period, i.e., 3 h in this case. Glucose additive is employed to serve a carbon precursor, which is carbonized and coated over the surface of LNCM crystals during the IR sintering process. The electrochemical performance of LNCM cathodes is well examined by charge-discharge cycling at 0.1 -5C. An appropriate carbon coating is capable of raising discharge capacity (i.e., 181.5 mAh g~(-1) at 0.1C), rate capability (i.e., 75.0 mAh g~(-1) at 5C), and cycling stability (i.e., capacity retention: 94.2% at 1C arter 50 cycles) of LNCM cathodes. This enhanced performance can be ascribed to the carbon coating onto the external surface of LNCM powders, creating an outer circuit of charge-transfer pathway and preventing cathode corrosion from direct contact to the electrolyte. Accordingly, the in-situ IR sintering technique offers a potential feasibility for synthesizing cathode materials commercially in large scale.