Intercalation Chemistry of the Disordered Rocksalt Li<sub>3</sub>V<sub>2</sub>O<sub>5</sub> Anode from Cluster Expansions and Machine Learning Interatomic Potentials
Xingyu Guo, Chi Chen, Shyue Ping Ong
Abstract
Disordered rocksalt (DRX) Li 3 V 2 O 5 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-Li 3 V 2 O 5 anode using density functional theory (DFT) calculations combined with machine learning cluster expansions and interatomic potentials. The predicted voltage profile of the DRX Li 3 V 2 O 5 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-Li 3 V 2 O 5 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-Li 3 V 2 O 5 anode and paves the way for the discovery of other disordered anode materials.