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 delivera high energy density of 109W h kg-1 and a high power output of 98W 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).