Olivine Coated Spinel: 5-Volt System for High Energy Lithium Batteries

摘要

LiMn_(0.5)Ni_(0.5)O_4 (LMN) has attracted considerable attention as 5-volt cathode materials for Li-ion batteries. Here, the coating of nano LiFePO_4 (LFP) onto the surface of the spinel particles is reported for the first time. Two processes were used to prepare LFP-coated LMN: a traditional sol-gel method in Ar and a mechano-fusion dry process, which provides a simple way to obtain surface coating for battery materials. Surface elemental analyses indicate that nano-LFP is intimately covered on the LMN surface. LiMn_(1.5)Ni_(0.5)O_4 showed better rate property especially at high rate (＞10C) after LiFePO_4 coating. Good performance such as 82 mAh g~(-1) of capacity was still obtained for the LiFePO_4-coated LiMni_(1.5)Ni_(0.5)O_4 with 75% of capacity retention after 140 cycles under 1C rate.