摘要
Abstract
Using density functional theory based on first-principles,theoretical calculations were con-ducted 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 de-creased,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 in-dicators,Fe doping exhibits the best overall performance.Based on lithium iron manganese phos-phate,Ni and Co were selected for dual-element doping modification as the second dopant.Com-pared 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Key words
olivine structure/dopant/lithium batteries/first-principles分类
动力与电气工程
