Effect of annealing time on the structural stability of LiCo0.55Ni0.4Ti0.05O2 cathode material via combustion method

Abstract

Layered LiNi1-xCoxO2 cathode material, particularly LiCo0.6Ni0.4O2 (LCN) in stoichiometry is one of the promising cathode materials as it possesses a good electrochemical behaviour and performances comparable with commercial LiCoO2 (LCO) cathode material. However, more improvement needs to be done in LCN cathode material in terms of higher toxic Co content and higher cation mixing in the material which mainly contributes to the structural instability and affects the capacity fading of the material. To combat both significant issues in the material, the stability of that material structure needs to be tackled first. In this study, Co was partially substituted with Ti4+ to give the LiCo0.55Ni0.4Ti0.05O2 (LCNT) cathode material using the combustion method. To get the optimum condition of LCNT, the precursor was then calcined at a temperature of 750°C for 24 hours, 48 hours and 72 hours and denoted as LCNT24, LCNT48, and LCNT72 respectively. XRD reveals that all samples are pure, single-phase with no impurities present except for LCNT72. Nano-sized LCNT24 sample has the highest RIR value of 1.84 indicating the lowest degree of cation Li+/Ni2+ mixing in the material and the most stable structure compared to others.