Cobalt Catalytic Regulation Engineering in Room‐Temperature Sodium–Sulfur Batteries: Facilitating Rapid Polysulfides Conversion and Delicate Na₂S Nucleation

Abstract

The sluggish conversion kinetics and uneven deposition of sodium sulfide (Na2S) pose significant obstacles to the practical implementation of room temperature sodium–sulfur (RT Na─S) batteries. To tackle these challenges, herein, a cathode host (Co‐NMCN) that enables rapid polysulfides conversion and delicate Na2S nucleation is developed via integrating Co nanoparticles into N‐doping multilayer carbon network. The freestanding carbon network expedites electronic transport and relives the electrode expansion, while the Co nanoparticles perform strong chemical adsorption with soluble sodium polysulfide (NaPSs) via Co─S bonds and exhibit remarkable electrocatalytic effect on the multi‐electron conversion of NaPSs. Density functional theory (DFT) calculations reveal a low energy barrier for NaPSs diffusion and Na₂S oxidation, which facilitates the uniform deposition of Na₂S across the scaffold in a controlled 3D nucleation process. This effectively mitigates the formation of irreversible by‐products and prevents electrocatalyst passivation, thus enhancing the overall reaction efficiency. As a result, the as‐prepared S@Co‐NMCN electrode delivers an impressive reversible capacity of 934.2 mA h g−1 at 0.5C and maintains a low decay rate of 0.064% per cycle over 800 cycles at 0.5C.