High-performance ZrO2-coated LiNiO2 cathode material

LiNiO2 with excellent structural stability and electrochemical reversibility is obtained by sol-gel coating of ZrO2. Significantly reduced lattice distortion is found in ZrO2-coated LiNiO2, showing several-times-lower changes in the lattice constants during charging, compared to that of bare sample. The thin-film encapsulation by ZrO2, with higher Zr concentration at the particle surface within similar to1 mum, can effectively suppress the lattice distortion and thereby phase transitions. The improved electrochemical reversibility is well demonstrated by the cycle-life performance in the coin-type half-cells (Li/coated-LiNiO2 and Li/bare-LiNiO2) between 4.3 and 2.75 V, showing only 2% capacity loss in the ZrO2-coated sample after 70 cycles. (C) 2001 The Electrochemical Society.