Enhancing the high-voltage electrochemical performance of Single-crystal LiNi0.5Co0.2Mn0.3O2 with mesoporous TiO2 coating and Ti doping

To improve the energy density of single-crystal LiNi0.5Co0.2Mn0.3O2 (NMC523) by increasing the charging cut-off voltage presents a big challenge since the material degrades significantly at high voltage (>4.3V). A simple method to enhance the high-voltage electrochemical properties of single-crystal NMC523 was proposed by introducing a mesoporous TiO2 coating and Ti doping. The specific discharge capacity for the modified NCM523-M-TiO2-0.5 sample achieves 182.81 mAh g−1 at a 0.1 C rate within the 3.0–4.5 V range. Furthermore, the capacity retention rate was 80.69 % after 200 cycles at a charge/discharge rate of 1 C, significantly higher than that of bare NCM523, which exhibited values of 181.36 mAh g−1 and 46.40 %. In detail, the mesoporous TiO2 coating shields the cathode from the electrolyte, enhancing the stability at the interface and promoting the movement of lithium ions. Additionally, Ti doping increases lattice spacing and stabilizes the layered structure. This research will inform the design of high-performance cathode materials for Li-ion batteries.