中国物理B ›› 2025, Vol. 34 ›› Issue (11): 118201-118201.doi: 10.1088/1674-1056/ae0bfe

• • 上一篇    下一篇

Comparative study on electronic structures of two phases compounds and origin of the structural phase transition in LiFePO4

Peiru Yang(杨佩如), Xinchun Du(杜新春), Jie Li(李杰)†, Siqi Shi(施思齐)‡   

  1. School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China
  • 收稿日期:2025-07-16 修回日期:2025-09-15 接受日期:2025-09-26 发布日期:2025-11-06
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 12304089) and the start-up foundation from Shanghai University. Calculations were partially performed on computers at the Shanghai Technical Service Center for Scientific and Engineering Computing, Shanghai University.

Comparative study on electronic structures of two phases compounds and origin of the structural phase transition in LiFePO4

Peiru Yang(杨佩如), Xinchun Du(杜新春), Jie Li(李杰)†, Siqi Shi(施思齐)‡   

  1. School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China
  • Received:2025-07-16 Revised:2025-09-15 Accepted:2025-09-26 Published:2025-11-06
  • Contact: Jie Li, Siqi Shi E-mail:lij@shu.edu.cn;sqshi@shu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 12304089) and the start-up foundation from Shanghai University. Calculations were partially performed on computers at the Shanghai Technical Service Center for Scientific and Engineering Computing, Shanghai University.

摘要: LiFePO$_{4}$ has normal olivine-structured ($\alpha $-LFP) and high pressure ($\beta $-LFP) phases, with the former being one of the cathode materials for commercial Li-ion batteries. Despite extensive focus on the respective electrochemical properties of the two phases, there is a lack of comparative studies on their electronic and magnetic properties, and the origin of the structural phase transition remains unclear. By combining first-principles calculations with molecular dynamics simulations, we find that the anisotropic compression of Li—O bonds drives the structural phase transition from $\alpha $-LFP to $\beta $-LFP at a critical pressure of 20 GPa, while $\beta $-LFP undergoes a transition from semiconductor to metal due to Fe$^{3+}$ generated during delithiation. Their antiferromagnetic (AFM) ground states are predicted to arise from the negative magnetic exchange interactions between nearest and next-nearest neighbor sites, with the corresponding Néel temperature showing significant enhancement under pressure. Furthermore, compared with $\alpha $-LFP, $\beta $-LFP shows increases in bulk, shear, and Young's moduli of 8%, 13%, and 12%, respectively. These findings enrich the physical property data of LiFePO$_{4}$ phase compounds, providing knowledge for expanding the application scenarios of the $\alpha $-LFP phase under special operating conditions such as high pressure.

关键词: lithium-ion battery, LiFePO4, structural phase transition, first-principles calculations

Abstract: LiFePO$_{4}$ has normal olivine-structured ($\alpha $-LFP) and high pressure ($\beta $-LFP) phases, with the former being one of the cathode materials for commercial Li-ion batteries. Despite extensive focus on the respective electrochemical properties of the two phases, there is a lack of comparative studies on their electronic and magnetic properties, and the origin of the structural phase transition remains unclear. By combining first-principles calculations with molecular dynamics simulations, we find that the anisotropic compression of Li—O bonds drives the structural phase transition from $\alpha $-LFP to $\beta $-LFP at a critical pressure of 20 GPa, while $\beta $-LFP undergoes a transition from semiconductor to metal due to Fe$^{3+}$ generated during delithiation. Their antiferromagnetic (AFM) ground states are predicted to arise from the negative magnetic exchange interactions between nearest and next-nearest neighbor sites, with the corresponding Néel temperature showing significant enhancement under pressure. Furthermore, compared with $\alpha $-LFP, $\beta $-LFP shows increases in bulk, shear, and Young's moduli of 8%, 13%, and 12%, respectively. These findings enrich the physical property data of LiFePO$_{4}$ phase compounds, providing knowledge for expanding the application scenarios of the $\alpha $-LFP phase under special operating conditions such as high pressure.

Key words: lithium-ion battery, LiFePO4, structural phase transition, first-principles calculations

中图分类号:  (Lithium-ion batteries)

  • 82.47.Aa
63.20.dk (First-principles theory)