First-Principles Study of the Impact of Grain Boundary Formation in the Cathode Material LiFePO4

• Published in: Condensed matter Vol. 4; no. 3; p. 80
• Main Authors: Kuriplach, Jan, Pulkkinen, Aki, Barbiellini, Bernardo
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-09-2019
• Subjects: Approximation; Cathodes; density functional theory; Electrode materials; First principles; Grain boundaries; grain boundary; Li-ion batteries; LiFePO4; Lithium; Lithium-ion batteries; Magnetic moments; Magnetic properties; Positrons; Rechargeable batteries; Spectrum analysis
• ISSN: 2410-3896; 2410-3896
• DOI: 10.3390/condmat4030080

Motivated by the need to understand the role of internal interfaces in Li migration occurring in lithium-ion batteries, a first-principles study of a coincident site lattice grain boundary in LiFePO4 cathode material and in its delithiated counterpart FPO4 is performed. The structure of the investigated grain boundary is obtained, and the corresponding interface energy is calculated. Other properties, such as ionic charges, magnetic moments, excess free volume, and the lifetime of positrons trapped at the interfaces are determined and discussed. The results show that while the grain boundary in LiFePO4 has desired structural and bonding characteristics, the analogous boundary in FePO4 needs to be yet optimized to allow for an efficient Li diffusion study.