Enabling stable NaS batteries via polysulfides anchoring and kinetics enhancement in synergistic hollow NiCo2S4/C scaffold

The shuttle effect, volume expansion, and slow conversion kinetics of sodium polysulfides (NaPSs) are significant challenges for room-temperature sodium‑sulfur batteries (RT Na S). To address these issues, this work designs a carbon-coated sulfur carrier (NiCo 2 S 4 ) with a unique hollow network structure. The unique structure provides ample space for sulfur's volume expansion, while the carbon material's excellent conductivity facilitates electron transport. Furthermore, the S@NiCo 2 S 4 /C composite cathode features a bimetallic sulfide framework that simultaneously provides strong anchoring and catalytic conversion functionality for polysulfides. Remarkably, the S@NiCo 2 S 4 /C cathode material maintains a capacity of 416.3 mA h g −1 after 400 cycles at 0.5C rate, with a cycle-dependent decay rate of merely 0.1%, demonstrating its excellent cycling stability and application potential. This study provides novel design concepts for cathode materials, which are essential for advancements in RT Na S batteries. This work designed and synthesized a carbon-coated NiCo₂S₄ hollow nanotube framework as a highly efficient sulfur host. During cycling, the polar NiCo 2 S 4 component not only chemically anchors sodium polysulfides to suppress dissolution but also acts as a catalyst to accelerate their redox conversion, thereby enhancing sulfur electroactivity. Therefore, the assembled cathode exhibits excellent cycling stability and rate performance in RT Na S batteries. Download: Download high-res image (159KB) Download: Download full-size image