Electrochemical performance of Al2O3-coated Fe doped LiCoVO4

Al2O3-coated LiCo0.94Fe0.06VO4 powders with improved electrochemical cycleability have been synthesized. The morphology and structure of the coating have been characterized with SEM, HR-TEM and XPS. It was found that the Al2O3 coating was amorphous and that the particles were not completely coated, approximately 30–40% of the surface was covered. The Al2O3 coating had an average thickness of 10 nm. Cyclic voltammetry measurements versus Li/Li+ showed that the Al2O3-coated LiCo0.94Fe0.06VO4 sintered at 600 °C showed the best capacity retention and the cycle tests revealed that the materials still possess a discharge capacity of 76 mA h g−1, even after 80 cycles. The improved cycling performance is attributed to the ability of the Al2O3 layer to neutralize the HF component in the liquid electrolyte.