Nano-Y2O3-coated LiNi0.5Co0.2Mn0.3O2 cathodes with enhanced electrochemical stability under high cut-off voltage and high temperature

LiNi0.5Co0.2Mn0.3O2 (523) coated with ~ 20 nm thick Y2O3 nano-membrane is prepared via a sol-type chemical precipitation process based on electrostatic attraction between the materials. The nano-Y2O3-coated 523 cathode can deliver 160.3 mA h g−1 (87.8% of its initial discharge capacity) after 50 cycles at 1 C (180 mA g−1) between 3.0 and 4.6 V by coin cell testing, while the pristine 523 keeps only 146.2 mA h g−1 with 78.6% capacity retention left. The capacity retention rate increases from 50% to 86.7% after 150 cycles at 1 C in 3.0-4.35 V by soft package testing under 45 °C. Through this novel Y2O3 coating operation, both the charge transfer resistance and the electrode polarization of the 523 electrode have been suppressed, and its structure stability is also improved.