Enhanced Electrochemical Performance of MOF-Derived Nitrogen-Enriched Porous Carbon Coated with Ag as the Cathode for Lithium-Sulfur Batteries

Abstract

To fulfill the increasing energy demand, lithium-sulfur batteries (LIBs) are considered one of the most promising energy storage devices for the next generation because of their high specific capacity (1675[Formula: see text]mAh[Formula: see text]g[Formula: see text] and high energy density (2600[Formula: see text]Wh[Formula: see text]kg[Formula: see text]. However, the low conductivity of electrode materials, large volume expansion rate and shuttle effect, rapid decline of battery capacity and low cycle lifetime have restricted the commercialization of LIBs. In this paper, a type of silver-coated Co@NC porous carbon (ZIF-67 derivatives) is used as the principal material of the lithium-sulfur battery cathode (denoted Ag–Co@NC). These composites not only confine the active materials to the ordered pore structure composites but also inhibit the free migration of polysulfide and improve the redox reaction. Furthermore, uniformly modified silver nanoparticles are beneficial for enhancing the conductivity of Li2S, thus exhibiting good rate performance and capacity and effectively improving the electrochemical performance of the material.