Enhanced electrochemical performances of 5Â V spinel LiMn1.58Ni0.42O4 cathode materials by coating with LiAlO2

LiAlO2-surface modified LiMn1.58Ni0.42O4 spinel cathode materials have been prepared by coating Al2O3 on Mn0.79Ni0.21CO3 precursors, followed by post-sintering with Li2CO3 at 900 °C. X-ray diffraction and FT-IR analyses indicate that during the calcination process aluminum ions not only react with Li2CO3 to form a strengthened LiAlO2 coating layer but also migrate from the surface into the spherical particles. The LiAlO2-surface modified LiMn1.58Ni0.42O4 samples exhibit excellent electrochemical performance compared to that of the bare one in terms of rate capability and cyclability. In particular, the 1 mol.% LiAlO2-surface modified sample can deliver a discharge capacity of 100.6 m Ah g−1 even at a high current density of 4 C-rate, while the bare one only has a discharge capacity of 49.5 m Ah g−1. At 55 °C, the 1 mol.% LiAlO2-surface modified LiMn1.58Ni0.42O4 sample shows outstanding cyclability with less than 5% capacity fade after 150 cycles. Based on these results, coating on the precursors to prepare a strengthened LiAlO2 coating layer would be a promising method to enhance the electrochemical performance of 5 V spinel cathode materials.