Sulfur‐Bridged Bonds Heightened Na‐Storage Properties in MnS Nanocubes Encapsulated by S‐Doped Carbon Matrix Synthesized via Solvent‐Free Tactics for High‐Performance Hybrid Sodium Ion Capacitors

Abstract The exploitation of electrode materials with ability to balance capacity and kinetics between cathode and anode is a challenge for sodium‐ion hybrid capacitors (SIHCs). Mn‐based anode materials are limited by poor electrical conductivity, sluggish reaction kinetics, large volume variation, weak cycling stability, and inferior reversible capacity. Herein, MnS nanocubes encapsulated in S‐doped porous carbon matrix (MSC) with strong sulfur‐bridged bond interactions (CSMn) are successfully synthesized by solvent‐free tactics. The CSMn bonds generated between MnS and carbon significantly inhibit the aggregation of nanostructural MnS cubes, restrict the volume expansion, and stabilize the nanostructure, which improves the Na⁺ storage reversibility and stability. Moreover, S‐doped porous carbon enhances the electrical conductivity and electrons/ions diffusion rate, which boosts a fast kinetic reaction. As expected, MSC anode presents an outstanding reversible capacity of 600 mAh g^‐1 at 0.2 A g^‐1 and a long‐term stable capacity of 357 mAh g^‐1 for 1000 cycles at a high current density of 10 A g^‐1 in sodium‐ion batteries (SIBs). The as‐assembled SIHCs deliver a high energy density of 109 W h kg^‐1 and a high power output of 98 W kg^‐1, with 88% capacity retention at 2 A g^‐1 after 2000 cycles and practical applications (55 LEDs can be lighted for 10 min).