Design principles of practical industrial-scale layered oxide cathodes with air/water stability for sustainable sodium-ion batteries

Low-cost manganese-based oxides as promising cathodes for sodium-ion batteries still face significant challenges, including irreversible phase transition, air/water sensitivity, and low initial charge capacity. Herein, we precisely design a titanium-substituted Mn-based oxide cathode material with optimized local electronic structure distribution through a stepwise screening mechanism based on theoretical calculations, which enables suppression of irreversible phase transition and Jahn-Teller distortion by exerting spring effect and pinning effect. Notably, the optimized cathode fabricated using an aqueous binder exhibits stable electrochemical performance, retaining 96.16 % of its capacity after 500 cycles at 1 A g−1, along with reliable air/water stability under prolonged exposure, which is further confirmed by advanced characterization and theoretical calculations. In addition, Prussian blue analogs are proposed as a sodium supplement for full cell applications. The large-scale production and implementation of composite cathode materials have been successfully achieved and subsequently applied in practical pouch cells with non-presodiated hard carbon anodes. This work investigates an air/water-stable Mn-based layered oxide cathode for sodium-ion batteries, providing insights relevant to their future industrial development.