Elemental Stability Rules for High Entropy Disordered Rocksalt Type Li-Ion Battery Positive Electrodes

Abstract

High entropy disordered rocksalt (HE-DRX) Li-ion battery positive electrodes have gained attention as a potential alternative to commercialized positive electrodes, aiming to eliminate or minimize the use of Ni/Co while maintaining competitive electrochemical performance. Despite their potential, understanding the intricate elemental stability across the vast HE-DRX chemical landscape remains a significant challenge. In this study, we tackle this challenge by conducting a comprehensive data-driven phase diagram analysis of 18810 potential HE-DRX compositions, each featuring common Li and F stoichiometries. Leveraging a charge balance algorithm, we systematically explore redox stability and phase stability, unveiling critical insights into chemical stability rules within the HE-DRX design space. The analysis also uncovers untapped potential of Cu as redox-active centers, with Sb and Sn contributing as stable charge compensators. The utilization of these elements is seldom reported in the literature but has been validated by the successful experimental synthesis of materials Li₂₁Zr₃Ti₃Mn₂Fe₅Cu₂O₃₆ and Li₂₁Mn₂Ti₃Fe₅Cu₂Sn₃O₃₆.