High Rate Capability and Excellent Thermal Stability of Li⁺-Conductive Li₂ZrO₃-Coated LiNi1/3Co1/3Mn1/3O₂ via a Synchronous Lithiation Strategy

A novel synchronous lithiation route has been successfully used to coat Li + -conductive Li 2 ZrO 3 on the surface of LiNi 1/3 Co 1/3 Mn 1/3 O 2 (Li 2 ZrO 3 @LNCMO). In this strategy, Li 2 ZrO 3 layer and LiNi 1/3 Co 1/3 Mn 1/3 O 2 host simultaneously form from ZrO 2 @Ni 1/3 Co 1/3 Mn 1/3 C 2 O 4 · x H 2 O precursor. In compared to bare LNCMO, the reversible capacity, cycling performance, thermal stability, rate capability, and polarization of Li 2 ZrO 3 @LNCMO have all been greatly improved. At 0.1 and 10 C, the specific capacity of Li 2 ZrO 3 @LNCMO is 192 and 106 mAh g –1, respectively, while they are 178 and 46 mAh g –1 for bare LNCMO. At a current density of 5 C, the capacity retention of Li 2 ZrO 3 @LNCMO at 25 and 55 °C after 400 cycles is enhanced to 93.8% and 85.1%, respectively, compared to 69.2% and 37.4% of bare LNCMO. The largely enhanced electrochemical performances of Li 2 ZrO 3 @LNCMO cathode can be attributed to the high Li-ion conductivity as well as the proctection of Li 2 ZrO 3 coating. Li + conductivity of Li 2 ZrO 3 @LNCMO is about 20 times higher than that of bare LNCMO. Moreover, the migration of partial Zr 4+ to the host LNCMO phase not only benefits Li-ion or electron conductivity but also alleviates the Li–Ni cation mixing and improves the structure stability. The cations migration, doping effect, and the reduced cation mixing further contribute to the electrochemical performance enhancement.