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采用水热法结合短时间高温烧结,通过将前驱体pH值从3.00调节到9.00,制备出多种形貌的纯相LiFePO4。对所得产物进行了X射线粉末衍射(XRD)测试、扫描电子显微镜(SEM)表征以及电化学性能测试,研究了前驱体pH值对LiFePO4的形貌和电化学性能的影响及其机理。结果表明,产物均为橄榄石型LiFePO4,并显示出由棒状物组成的空心球形、凹陷形以及菱形和多层菱形等多种形貌。不同形貌LiFePO4的电化学性能差异较大,当前驱体pH=6.00时电化学性能最佳,在0.1C和5C下首次放电比容量分别为163mAh.g-1和100mAh.g-1。
Hydrothermal method combined with short-time high-temperature sintering, by adjusting the precursor pH from 3.00 to 9.00, prepared a variety of morphology of pure phase LiFePO4. The obtained product was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and electrochemical properties. The effects of precursor pH value on the morphology and electrochemical performance of LiFePO4 were investigated. The results showed that the products were all olivine LiFePO4, and showed hollow spheres, hollows and many rhombohedral and multi-layered diamonds. The electrochemical properties of LiFePO4 with different morphologies are quite different. The electrochemical performance of LiFePO4 is best at pH = 6.00. The initial discharge specific capacities of LiFePO4 are 163mAh.g-1 and 100mAh.g-1 at 0.1C and 5C, respectively.