Thermodynamics of multi-sublattice battery active materials

Thermodynamics of multi-sublattice battery active materials: from an extended regular solution theory to a phase-field model of LiMn_yFe_1-yPO₄

Ombrini, P. (TU Delft RST/Storage of Electrochemical Energy)
Bazant, Martin Z. (Massachusetts Institute of Technology)
Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)
Vasileiadis, A. (TU Delft RST/Storage of Electrochemical Energy)

2023

Phase separation during the lithiation of redox-active materials is a critical factor affecting battery performance, including energy density, charging rates, and cycle life. Accurate physical descriptions of these materials are necessary for understanding underlying lithiation mechanisms, performance limitations, and optimizing energy storage devices. This work presents an extended regular solution model that captures mutual interactions between sublattices of multi-sublattice battery materials, typically synthesized by metal substitution. We apply the model to phospho-olivine materials and demonstrate its quantitative accuracy in predicting the composition-dependent redox shift of the plateaus of LiMn_yFe_1-yPO₄ (LFMP), LiCo_yFe_1-yPO₄ (LFCP), LiCo_xMn_yFe_1-x-yPO₄ (LFMCP), as well as their phase separation behavior. Furthermore, we develop a phase-field model of LFMP that consistently matches experimental data and identifies LiMn_0.4Fe_0.6PO₄ as a superior composition that favors a solid solution phase transition, making it ideal for high-power applications.

http://resolver.tudelft.nl/uuid:01469449-f076-4c01-9873-88a2ae91e36c

https://doi.org/10.1038/s41524-023-01109-1

2057-3960

npj Computational Materials, 9 (1)

Institutional Repository

journal article

© 2023 P. Ombrini, Martin Z. Bazant, M. Wagemaker, A. Vasileiadis