Non‐trivial Contribution of Carbon Hybridization in Carbon‐based Substrates to Electrocatalytic Activities in Li‐S Batteries

Abstract

Appling an electrochemical catalyst is an efficient strategy for inhibiting the shuttle effect and enhancing the S utilization of Li-S batteries. Carbonbased materials are the most common conductive agents and catalyst supports used in Li-S batteries, but the correlation between the diversity of hybridizations and sulfur reduction reaction (SRR) catalytic activity remains unclear. Here, by establishing two forms of carbon models, i.e., graphitic carbon (GC) and amorphous carbon (AC), we observe that the nitrogen atom doped in the GC possesses a higher local charge density and a lower Gibbs free energy towards the formation of polysulfides than in the AC. And the GC-based electrode consistently inherits considerably enhanced SRR kinetics and superior cycling stability and rate capability in Li-S batteries. Therefore, the function of carbon in Li-S batteries is not only limited as conductive support but also plays an unignorable contribution to the electrocatalytic activities of SRR.

Three-Dimensional Nitrogen-Doped Carbon Nanoskeleton Cladded with a Graphitic C3N5 Nanolayer as a Sulfur Host for Lithium–Sulfur Batteries

“…14,17−22 Because of their smart conductivity, flexible structural tailorability with large specific surface area and curtailed cost, carbon-based nanomaterials have been widely investigated as sulfur hosts for LSBs. 19,23 However, pristine carbon-based nanomaterials with nonpolar carbon−carbon bonds show faint affinity to LiPS intermediates and hence weak suppression of the shuttle effect.…”