TiO₂ Nanoparticles Assisted LiNbO₃‑Coated LiNi_0.8Co_0.1Mn_0.1O₂ Cathode for Lithium-Ion Batteries

Abstract

Ni-rich\nlayered-oxide cathode materials (NCM) are widely recognized\nfor their high capacity and low cost, so that they have become the\nmost promising cathode materials, but the low cycle performance limits\ntheir application. Therefore, LiNbO₃ with high Li⁺ conductivity was considered as a coating design for NCM. However,\nthe traditional LiNbO₃ wet coating method adopts an expensive\nNb source to be prepared. Herein, we first prepared LiNbO₃ using niobium hydroxide as a Nb source to replace niobium ethoxide\nand designed a coating strategy that nano-TiO₂ as a carrier\nto fulfill LiNbO₃ coated on LiNi_0.8Co_0.1Mn_0.1O₂(NCM811). The coating strategy promotes\nLi⁺ conductivity between the cathode particles and helps\nto shield the contact between the cathode and electrolyte. Moreover,\nthe high specific surface area of nano-TiO₂ was used to\ncontrol the coating size of LiNbO₃. At 700 °C sintering\ntemperature, a slight amount of the Ti element was doped into LiNbO₃ to further improve its ionic conductivity. Thus, 1 wt % TiO₂ and LiNbO₃-modified NCM811 exhibited 25 mAh g^–1 capacity improvement (at 1 C, 25 °C) for liquid\nlithium-ion battery, then showed 24.7 and 49.1 mAh g^–1 capacity improvement (0.2 and 1 C, respectively) and higher capacity\nretention (79.52% vs 58.60% for bare NCM811 after 100 cycles) for\nPVDF-based solid-state batteries.