Copper‐Stabilized Sulfur‐Microporous Carbon Cathodes for Li–S Batteries

Abstract

A copper‐stabilized sulfur‐microporous carbon (MC‐Cu‐S) composite is synthesized by uniformly dispersing 10% highly electronically conductive Cu nanoparticles into microporous carbon (MC), followed by wet‐impregnating S. In the MC‐Cu‐S composite, the MC host that physically confines S/polysulfides provides free space to accommodate volumetric expansion of S during lithiation, while the Cu nanoparticles that are anchored in the MC further chemically interact with S/polysulfides through bonding between Cu and S/polysulfides. The Cu loading allows the S content to increase from 30 to 50% in the carbon‐S cathode material without scarifying the electrochemical performance in a low‐cost carbonate electrolyte. At a current density of 100 mA g‐1, the MC‐Cu‐S cathode shows that Coulumbic efficiency is close to 100% and capacity maintains more than 600 mAh g‐1 with progressive cycling up to more than 500 cycles. In addition, the Cu nano‐inclusins also enhance the electronic conductivity of the MC‐Cu‐S composite, remarkably increasing the rate capabilities. Even the current density increases 10.0 A g‐1, the MC‐Cu‐S cathode can still deliver a capacity of 200 mAh g‐1. This strategy of stabilization of S with small amount of metal nanoparticles anchored in MC provides an effective approach to improve the cycling stability, Coulumbic efficiency, and S loading for Li–S batteries.