O‐Tailored Microstructure‐Engineered Interface toward Advanced Room Temperature All‐Solid‐State Na Batteries

Abstract

The severe parasitic interface reaction and dendrite growth retard the practical applications of all-solid-state (ASS) Na batteries with sulfide solid electrolytes (SEs). Here, a novel composite SE is proposed, with a high ionic conductivity, composed of Na3SbS4 (NSS) and oxysulfide glass. The study reveals that the P2S7-aOa and PS4-aOa units in oxysulfide play various roles: The former is deoxidized to release free O ions, which reacts with the anode via migrating to form oxides, favoring an improved interface stability. The latter is highly stable upon cycling, thereby maintaining an ion transport network. Meanwhile, NSS acts as a dendrite predator via reacting with penetrated Na. These advantages enable the resulting ASS Na battery with superior long-term cycling performance at a high current density at room temperature, one of the best results so far. This discovery sheds light on innovative advanced SE materials through an oxysulfide-based composite design.