Enhancing Conversion Kinetics through Electron Density Dual‐Regulation of Catalysts and Sulfur toward Room‐/Subzero‐Temperature Na–S Batteries

Abstract

Abstract Room‐temperature sodium–sulfur (RT Na/S) batteries have received increasing attention for the next generation of large‐scale energy storage, yet they are hindered by the severe dissolution of polysulfides, sluggish redox kinetic, and incomplete conversion of sodium polysulfides (NaPSs). Herein, the study proposes a dual‐modulating strategy of the electronic structure of electrocatalyst and sulfur to accelerate the conversion of NaPSs. The selenium‐modulated ZnS nanocrystals with electron rearrangement in hierarchical structured spherical carbon (Se‐ZnS/HSC) facilitate Na+ transport and catalyze the conversion between short‐chain sulfur and Na2S. And the in situ introduced Se within S can enhance conductivity and form an S─Se bond, suppressing the “polysulfides shuttle”. Accordingly, the S@Se‐ZnS/HSC cathode exhibits a specific capacity of as high as 1302.5 mAh g−1 at 0.1 A g−1 and ultrahigh‐rate capability (676.9 mAh g−1 at 5.0 A g−1). Even at −10 °C, this cathode still delivers a high reversible capacity of 401.2 mAh g−1 at 0.05 A g−1 and 94% of the original capacitance after 50 cycles. This work provides a novel design idea for high‐performance Na/S batteries.

Keywords

• dual‐modulating strategy
• electron density
• selenium
• sodium‐sulfur batteries
• ZnS