锂离子电池LiFePO4/Li3V2(PO4)3复合正极材料的制备及性能研究

为了提高LiFePO₄正极材料的离子导电性，采用液相共沉淀法与碳热还原法制备一系列质量配比的LiFePO₄/Li₃V₂(PO₄)₃复合材料，通过X-射线衍射、扫描电镜、恒流充放电测试仪等分析测试手段测试样品。研究发现，m(LiFePO₄):m(Li₃V₂(PO₄)₃)=6:4时复合材料形貌较为规则且结晶度较高，在0.1C，1.0C，2.0C，5.0C，10.0C倍率下放电比容量可达148，136，130.5 ，121.5，112.3 mA·h·g-1，1C倍率下循环100次容量保持率仍可达98.5%，有效地解决了LiFePO₄离子电导率低的问题，推动了该复合正极材料在动力型锂离子电池中的应用。

Preparation and properties of LiFePO4/Li3V2 (PO4)3 compositecathode material for lithium-ion batteries

LiFePO₄/Li₃V₂(PO₄)₃composite cathode materials with a series of mass ratios were synthesized using the liquid-phase co-precipitation method and carbon thermal-reduction process to improve the electronic conductivity of LiFePO₄cathodes. X-ray diffraction, scanning electron microscopy, constant-current charge and discharge testing, and other analytical methods were used to analyze the phase composition, morphology, and electrochemical performance of the composites. When the mass ratio of LiFePO₄ and Li₃V₂(PO₄)₃ was 6:4, the composite exhibited regular morphology, higher crystallinity, and the best electrochemical performance: the discharge capacity was 148, 130.5, 121.5,and 112.3 mA·h·g-1 at rates of 0.1C, 1.0C, 2.0C, 5.0C, and 10.0C, respectively, and the capacity remained above 98.5% after 100 cycles at 1C. This effectively solves the problem of low conductivity of the LiFePO₄ material and will accelerate its application in power lithium-ion batteries.