大比表面积CoOOH包覆高电压钴酸锂的性能研究

Study on Coating Properties of CoOOH with High Specific Surface Area for High-Voltage LiCoO2

摘要:

采用液相沉淀-低温热分解法制备了大比表面积羟基氧化钴，通过XRD、SEM和激光粒度仪对样品的结构和形貌进行表征，结果表明所制备的产物主相为CoOOH，其比表面积达到60 m²?g^-1，形貌呈片状颗粒，中位径D₅₀为0.13 μm。同时，研究了大比表面积CoOOH对钴酸锂正极材料的包覆性能及电化学性能。SEM结果表明，大比表面积CoOOH均匀地覆盖在钴酸锂颗粒表面。电性能测试结果表明，CoOOH包覆的钴酸锂在电压3.0—4.6 V范围内经100次循环充放电后，其容量保持率达到87.9%，优于氢氧化钴。

Abstract:

The CoOOH with a high specific surface area was prepared by liquid phase precipitation-thermal decomposition at low temperatures. The structure and morphology of the as-prepared sample were tested by X-Ray diffraction， scanning electron microscopy， and laser particle size analyzer. The results showed that the main phase of the product was CoOOH， whose specific surface area and median diameter D₅₀ of the powder were 60 m²?g^-1 and 0.13 μm， respectively. The coating performance and electrochemical properties of CoOOH with a large specific surface area on LiCoO₂ were studied， The SEM results displayed that the CoOOH with a large specific surface area was evenly covered on the surface of LiCoO₂. The electrochemical properties test results showed that the CoOOH-coated LiCoO₂ had a capacity retention rate of 87.9% after 100 cycles of charging and discharging at a voltage range of 3.0—4.6 V， which is better than that of Co（OH）₂.