Intercalation Chemistry of the Disordered Rocksalt Li3V2O5 Anode from Cluster Expansions and Machine Learning Interatomic Potentials

Abstract

Disordered rocksalt (DRX) Li3V2O5 is a promising anode candidate for rechargeable lithium-ion batteries because of its low voltage, high rate capability, and good cycling stability. Herein, we present a comprehensive study of the intercalation chemistry of the DRX-Li3V2O5 anode using density functional theory (DFT) calculations combined with machine learning cluster expansions and interatomic potentials. The predicted voltage profile of the DRX Li3V2O5 anode at room temperature based on Monte Carlo simulations with a fitted cluster expansion model is in good agreement with experiments. In contrast to previous DFT results, we find that Li ions predominately intercalate into tetrahedral sites during charging, while a majority of Li and V ions at octahedral sites remain stable. In addition, molecular dynamics simulations with a fitted moment tensor potential attribute the fast-charging capability of DRX-Li3V2O5 to the facile diffusivity of Li+ via a tetrahedral–octahedral–tetrahedral pathway. We further suggest tuning the Li:V ratio as a means of trading off increased lithiation capacity and decreased anode voltage in this system. This work provides in-depth insights into the high-performance DRX-Li3V2O5 anode and paves the way for the discovery of other disordered anode materials.