Improved electrochemical performances of high voltage LiCoO2 with tungsten doping**Project supported by the National Key Rerearch and Development Program of China (Grant No. 2017YFB0102004), the National Natural Science Foundation of China (Grant No. 51502334), the Fund from Beijing Municipal Science & Technology Commission, China (Grant No. D171100005517001), and the Thousand Talent Program for Outstanding Young Scientists, China.

Abstract

The effects of tungsten W doping and coating on the electrochemical performance of LiCoO2 cathode are comparatively studied in this work. The amount of modification component is as low as 0.1 wt% and 0.3 wt% respectively. After 100 cycles between 3.0 V–4.6 V, 0.1 wt% W doping provides an optimized capacity retention of 72.3%. However, W coating deteriorates battery performance with capacity retention of 47.8%, even lower than bare LiCoO2 of 55.7%. These different electrochemical performances can be attributed to the surface aggregation of W between doping and coating methods. W substitution is proved to be a promising method to develop high voltage cathodes. Practical performance relies on detailed synthesis method.