Influence of precursor phase on the structure and electrochemical properties of Li(Ni0.6Mn0.2Co0.2)O-2 cathode materials

LiNi0.6CO0.2Mn0.2O2 (NCM622) cathode materials are prepared via sintering the mixtures of (Ni0.6Mn0.2Co0.2) (OH)(2) precursor and LiOH. The effects of the beta-(Ni0.6Mn0.2Co0.2)(OH)(2) content in hydroxide precursor on the structure and electrochemical performance of NCM622 cathode materials are investigated. Among three kinds of cathodes, the cathode material sintered from beta-(Ni0.6Mn0.2Co0.2)(OH)(2) phase precursor exhibits the excellent layered structure with the highest c/a value. Furthermore, it displays the excellent hexagonal ordering with the lowest ratio of I(006+ 102)/I-(101). With increasing the beta-(Nia(0.6)Mn(0.2)Co(0.2))(OH)(2) phase content in precursors, the discharge capacity of NCM622 samples first increases, and then decreases. The cathode material sintered from the mixed phase of alpha-(Ni0.6Mn0.2Co0.2)(OH)(2) and beta-(Ni0.6Mn0.2Co0.2)(OH)(2) shows the highest discharge capacity of 192.1tnAh/g and best rate performance, and then is the best recommendation for a high-power cathode. While the cathode material sintered from single beta-(Ni0.6Mn0.2Co0.2)(OH)(2) phase shows the best cycle stability and the capacity retention of 91.7% after 100 cycles, and then is the best recommendation for a long-life cathode.