Systematic Theoretical Investigation of Li5NbWO8 as a Novel Solid Electrolyte via First-Principles Calculations

Abstract

Through systematic first-principles calculations combined with thermodynamic analysis and molecular dynamics simulations, this study provides an in-depth exploration of the potential of the novel lithium-niobiumtungsten oxide, Li5NbWO8, as a "multi-functional integrated" solid electrolyte.The work confirms that this material possesses excellent thermodynamic stability and High oxidation limit (~3.61 V vs. Li⁺/Li), which is significantly superior to that of the classic garnet electrolyte LLZO (~2.9 V). The Calculation results demonstrate that Li5NbWO8 exhibits exceptional lithium-ion conduction performance, with a predicted room-temperature ionic conductivity of 3.39 mS/cm and an activation energy of 0.26 eV. At the microscopic level, the lithium-ion transport is revealed to originate from the concerted migration mechanism and optimized three-dimensional diffusion channels introduced by the Nb doping in W site. Further interfacial thermodynamic analysis indicates that the material shows good chemical compatibility with high-voltage layered oxide cathodes (e.g., LiCoO2 and LiNiO2) across a wide range of states of charge. This is attributed to its unique design of a "highest-valence cation framework coupled with lithium-rich matrix," which effectively suppresses interfacial side reactions. This work elucidates, from the atomic scale, the critical role of the "niobium-tungsten synergistic effect" in enhancing both ionic conductivity and interfacial stability, thereby providing a new material design concept and theoretical foundation for the development of high-performance solid electrolytes aimed at high-energy-density all-solid-state batteries.