磷酸锰锂掺杂改性的第一性原理研究  

First-principles study on doping modification of lithium manganese phosphate

作　　者：丁爽 刘恋 周江 DING Shuang;LIU Lian;ZHOU Jiang(CETC LANTIAN Technology Co.,Ltd.,Tianjin 300384,China)

机构地区：[1]中电科蓝天科技股份有限公司,天津300384

出　　处：《电源技术》2025年第4期733-739,共7页Chinese Journal of Power Sources

摘　　要：基于第一性原理利用密度泛函理论对磷酸锰锂材料改性进行了理论计算。相较于磷酸铁锂,磷酸锰锂在比容量接近的基础上具有较高电压,但其电导率和锂离子扩散系数较低,电化学性能差。因此,通过掺杂方式对磷酸锰锂材料进行改性来提高其电化学性能,达到兼顾高比能量和高安全性,其衡量指标为体积变化、电子电导率、电压、锂离子传输性质和热力学稳定性。选取Fe,Co,Ni,Nb,Ti这五种元素进行掺杂改性,掺杂异种元素后,材料的带隙均减小,提高了电子电导率;Ni、Co掺杂提高了磷酸锰锂的电压,但降低了材料的安全性;五种衡量指标的雷达图显示,Fe掺杂后综合性能最佳。在磷酸锰铁锂材料基础上选取Ni、Co进行第二种元素掺杂改性。相较于Ni掺杂改性,Co掺杂进一步提高了材料的电子电导率。Using density functional theory based on first-principles,theoretical calculations were conducted on the modification of lithium manganese phosphate(LiMnPO4)materials.Compared with LiFePO4,LiMnPO4 offers a higher voltage with a comparable specific capacity,but it suffers from low electrical conductivity and lithium-ion diffusion coefficients,resulting in poor electrochemical performance.Therefore,this paper aimed to enhance the electrochemical performance of LiMnPO4 materials through doping modification,achieving a balance between high energy density and high safety.The evaluation indicators include volume change,electronic conductivity,voltage,lithium-ion diffusion,and thermodynamic stability.Five elements,namely Fe,Co,Ni,Nb,and Ti,were selected for doping modification.After doping with heterologous elements,the band gap of the materials decreased,leading to improved electronic conductivity.Ni and Co doping increased the voltage of Li-MnPO4 but compromised the material's safety.According to the radar chart of the five evaluation indicators,Fe doping exhibits the best overall performance.Based on lithium iron manganese phosphate,Ni and Co were selected for dual-element doping modification as the second dopant.Compared with Ni doping,Co doping further improves the electronic conductivity of the material.

关 键 词：橄榄石结构 掺杂 锂离子电池 第一性原理 

分 类 号：TM912.9[电气工程—电力电子与电力传动]