Biomimetic Porous Carbon of Marine Sponge for High Performance Cathode of Li-S Battery.

Abstract

The electrochemical performance of lithium-sulfur batteries is hindered by the shuttle effect of lithium polysulfides, the poor electrical conductivity of sulfur, and sluggish redox kinetics of sulfur species. By mimicking the high-efficiency mass transport, excellent nutriment capture capability, and rapid catalytic conversion properties of marine sponges, a multifunctional bicontinuous mesoporous carbonaceous sulfur host incorporated with Co single atoms (denoted as bimeso-CoNC) is constructed as a cathode material for Li-S batteries. The 3D interconnected mesochannels in bimeso-CoNC enhance the Li⁺ transport and sulfur loading, while the incorporated Co single atoms exhibit strong polysulfide adsorption and accelerate the kinetics of polysulfide conversion. Remarkably, the bimeso-CoNC/S-based cathode delivers a high capability of 570.0 mAh g^-1 at 6 C, a high areal capacity of 11.6 mAh cm^-2 at an ultrahigh sulfur loading of 13.5 mg cm^-2, and remarkable long-term stability (over 1200 cycles with 0.039% capacity decay per cycle). The comprehensive performance ranks among the best of the reported carbon-based cathode materials for Li-S batteries. This study presents a pore engineering strategy to improve the loading and adsorption of sulfur as well as accelerate the sulfur redox kinetics in Li-S batteries, which remarkably suppresses the shuttling effect and thus enhances the performance of Li-S batteries.