An improved carbonate co-precipitation method for the preparation of spherical Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 cathode material

摘要

An improved carbonate co-precipitation method was employed to prepare spherical Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 cathode material. The precursor, [Ni_(1/3)Co_(1/3)Mn_(1/3)]CO_3, was prepared using ammonia as chelating agent under CO_2 atmosphere. The spherical Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 was prepared by mixing the precal-cined [Ni_(1/3)Co_(1/3)Mn_(1/3)]CO_3 with 7 percent excess LiOH followed by high-temperature calcination. Compared with the Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 prepared by the conventional carbonate co-precipitation method, the Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 prepared by the improved carbonate co-precipitation method showed larger specific surface area and better electrochemical performance. The initial discharge capacity of the Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 prepared by the improved carbonate co-precipitation method was 162 mAh g~(-1) and 96.6 percent of the initial discharge capacity was retained after 50 charge-discharge cycling. However, the tap density of the Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 prepared by the improved carbonate co-precipitation method is lower than that of the Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 prepared by the conventional carbonate co-precipitation method, and the tap densities of both Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 samples are lower than that of the Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 prepared by the hydroxide co-precipitation method.