Synthesis and electrochemical performances of high-voltage LiNi_0.5Mn_1.5O₄ cathode materials prepared by hydroxide co-precipitation method

Shuang Li¹，Yue Yang²，Ming Xie³，Qin Zhang¹

1. College of Mining, Guizhou University2. Institute of Nuclear and New Energy Technology, Tsinghua University3. The State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Precious Metals

摘 要：Spherical cathode material LiNi_0.5Mn_1.5O₄ for lithium-ion batteries was synthesized by hydroxide coprecipitation method. X-ray diffraction（XRD）, scanning electron microscopy（SEM） and electrochemical measurements were carried out to characterize prepared LiNi_0.5Mn_1.5O₄ cathode material. SEM images show that the LiNi_0.5Mn_1.5O₄ cathode material is constituted by micro-sized spherical particles（with a diameter of around 8 μm）. XRD patterns reveal that the structure of prepared LiNi_0.5Mn_1.5O₄ cathode material belongs to Fd3m space group. Electrochemical tests at 25 °C show that the LiNi_0.5Mn_1.5O₄ cathode material prepared after annealing at 600 °C has the best electrochemical performances. The initial discharge capacity of prepared cathode material delivers 113.5 mAh·g^-1 at 1C rate in the range of 3.50–4.95 V, and the sample retains 96.2%（1.0C） of the initial capacity after 50 cycles. Under different rates with a cutoff voltage range of 3.50–4.95 V at 25 °C, the discharge capacities of obtained cathode material can be kept at about 145.0（0.1C）, 126.8（0.5C）, 113.5（1.0C）and 112.4 mAh·g^-1（2.0C）, the corresponding initial coulomb efficiencies retain above 95.2%（0.1C）, 95.0%（0.5C）, 92.5%（1.0C） and 94.8%（2.0C）, respectively.

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