Altered S–S Coulomb Interactions in Polysulfides Associated with VS₂/S Nanocomposite Electrodes for Na–S Batteries

Abstract

Despite the abundant reserves and high theoretical capacity of Na−S batteries, it is still limited by the sluggish reaction kinetics of polysulfides during ultrafast charging and discharging to provide stable and high sodium-ion storage performance. Herein, a catalytic strategy is proposed to change the direction of the Coulomb interaction of S−S bonds to achieve high rate reaction kinetics in polysulfides. In this strategy, a Na x VS 2 structure is constructed in VS 2 /S nanocomposite electrodes to support S for superior performance (784 mA h/g at 0.1 A/g and 512 mA h/g at 10 A/g) during sodium storage process. The electrode can still exhibit stable cycling performance at a very high current density (5000 cycles at 20 A/g). The Na-inserted VS 2 (Na x VS 2 ) changes the charge distribution of S in polysulfide molecules, altering the Coulomb interaction between S atoms in polysulfide to form repulsion-induced breaking of S−S bond. This altering effect on the atomic Coulomb interaction is essential to promoting the conversion reaction of polysulfides. The above strategy of changing the Coulomb interaction between S atoms not only provides a reference for the design of nanostructures for electrochemical processes with multistep reactions but also inspires angles and ideas for realizing high-performance Na−S batteries.

Cobalt–Nitrogen Bonding for Triggering the Low-Power Dual Detection of NO2 and NH3 by Mixed-Valence Co2+ and Co3+

“…Nanostructuring, such as mixing, decoration, doping, and/or functionalization, has demonstrated the capability of enhancing surface-to-volume ratio, porosity, surface energies, geometric, electronic, and chemical effects that are critically significant not only for gas sensing but also biosensing, energy, and environmental applications, such as batteries, solar cells, photocatalysis, capacitors, catalysis, and OER . A plethora of literature on the valence of surface ions demonstrates different mechanisms for different applications .…”