Polyoxovanadates as Effective Coating Materials for Layered Ni-Rich Oxide Cathodes in Liquid- and Solid-State Batteries

Abstract

Advanced coatings for improving the electro-chemo-mechanical stability of high-capacity, layered Ni-rich oxide cathode materials play an important role in modern battery technology. Vanadium-based protective coatings are particularly promising owing to their ability to provide high ionic conductivity and their intrinsic robustness. In addition, diminishing or eliminating residual lithium through surface coating shows great promise in mitigating capacity loss and addressing associated challenges. Herein, we report on a strategic exploration of a facile coating approach for Ni-rich LiNi_xCo_yMn_1−x−yO₂ (NCM851005, 85 % Ni content) utilizing polyoxovanadate. Specifically, TBA₃H₃[V₁₀O₂₈] was applied due to its solubility in non-aqueous media, avoiding H₂O-induced side reactions and achieving a more uniform surface coverage. The cycling performance of NCM851005 before and after modification was tested in conventional Li-ion cells, as well as in all-solid-state batteries with a lithium thiophosphate superionic electrolyte. Our findings highlight the potential of polyoxovanadate-derived protective coatings for improving the cyclability of Ni-rich cathodes.