The effect of Ti4+, Mg2+ co-doping on performance of LiNi0.4Co0.2Mn0.4O2

The effect of co-doping with Ti and Mg ions in LiNi0.4Co0.2Mn0.4O2 on structure and electrochemical performance was investigated by using SEM, XRD, EIS and galvanostatic charge-discharge experiment. The XRD showed that some characteristic peak intensity ratios have significant change. The rate discharge capability and cycle stability of LiNi0.4Co0.2Mn0.4O2 can be improved significantly by a small amount of Ti, Mg ions co-doping(1% molar ratio). AC impedance was used to study the processes of charge-discharge cycle. The result showed that (Ti4+, Mg2+) multiple-ion dopant can evidently suppress the increasing of the electrochemical reaction resistant R-ct at 1C & 2C discharge rates. Co-doping of metal ions with diferent valences is a useful method to improve large current discharge capability of the lithium insertion nickel cobalt manganese oxides.