磷酸锰铁锂材料的制备及其性能研究  

Preparation and Performance Study of LiFe_(0.5)Mn_(0.5)PO_(4)Materials

作　　者：杨金星 赵夷婷 巫运辉 YANG Jinxing;ZHAO Yiting;WU Yunhui(School of Materials Science and Engineering,Dongguan University of Technology,Dongguan 523808,China)

机构地区：[1]东莞理工学院材料科学与工程学院,广东东莞523808

出　　处：《东莞理工学院学报》2025年第1期100-106,共7页Journal of Dongguan University of Technology

基　　金：国家自然科学基金(52103255)。

摘　　要：磷酸锰铁锂作为锂离子电池重要的正极材料之一,近年来受到科研工作者的广泛关注,该材料具有较高的能量密度、良好的安全性和循环稳定性。采用水热法制备纳米尺寸的磷酸锰铁锂材料,并对其性能进行详细研究。电化学测试结果表明该材料的放电比容量高达168 mAh g^(-1)@0.1C,同时其能量密度为650 Wh kg^(-1),具有良好的长循环寿命。原位电化学阻抗谱分析证实了合成纳米尺寸的磷酸锰铁锂材料可有效缓解Mn^(3+)的Jahn-Teller效应引起的MnO_(6)八面体的晶格畸变,并能够提高锂离子的扩散系数,提升材料的电化学性能。长循环测试后电极材料截面分析表明电极中的集流体与活性物质结合不紧密,电化学阻抗谱中的电荷转移电阻R ct阻值增大,锂离子扩散系数降低,阻碍了锂离子的迁移,从而导致磷酸锰铁锂扣式电池经过长循环测试后容量发生衰减。LiMn_(0.5)Fe_(0.5)PO_(4),as one of the important positive electrode materials for lithium-ion batteries,has received widespread attention from researchers in recent years.This material has high energy density,good safety,and cycling stability.The nano-sized lithium LiMn_(0.5)Fe_(0.5)PO_(4)materials was prepared by hydrothermal method and its properties were studied in detail.The electrochemical test results show that the discharge specific capacity of the material is as high as 168 mAh g^(-1)@0.1C At the same time,its energy density is 650 Wh kg^(-1),and it has a good long cycle life.In situ electrochemical impedance spectroscopy analysis confirms that the synthesis of nano-sized LiMn_(0.5)Fe_(0.5)PO_(4)materials can effectively alleviate the lattice distortion of MnO_(6)octahedra caused by the Jahn-Teller effect of Mn^(3+),and improve the diffusion coefficient of lithium ions,optimizing the electrochemical performance of the material.After long cycle testing,cross-sectional analysis showed that the current collector in the electrode was not tightly bound to the active material.The charge transfer resistance R ct in the electrochemical impedance spectrum increased,and the diffusion coefficient of lithium ions decreased,which hindered the migration of lithium ions and led to capacity degradation of the manganese iron phosphate lithium battery after long cycle testing.

关 键 词：锂离子电池 磷酸锰铁锂 水热法 电化学性能 

分 类 号：H0-06[语言文字—语言学]