Li₄SiO₄-coated LiNi_0.5Mn_1.5O₄ as the high performance cathode materials for lithium-ion batteries

Abstract

The preparation of Li₄SiO₄-coated LiNi_0.5Mn_1.5O₄ materials by sintering the SiO₂-coated nickel-manganese oxides with lithium salts using abundant and low-cost sodium silicate as the silicon source was reported. The samples were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It was found that a uniform and complete SiO₂ coating layer could be obtained at a suitable pH value of 10, which transformed to a good Li₄SiO₄ coating layer afterwards. When used as the cathode materials for lithium-ion batteries, the Li₄SiO₄-coated LiNi_0.5Mn_1.5O₄ samples deliver a better electrochemical performance in terms of the discharge capacity, rate capability, and cycling stability than that of the pristine material. It can still deliver 111.1 mAh/g at 20 C after 300 cycles, with a retention ratio of 93.1% of the stable capacity, which is far beyond that of the pristine material (101.3 mAh/g, 85.6%).

Keywords

lithium-ion batteries / cathode material / LiNi_0.5Mn_1.5O₄ / lithium-ion conductor / coating

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Higher Education Press and Springer-Verlag Berlin Heidelberg