Indium/cobalt nanoparticles impregnated porous nitrogen-doped carbon matrix as a 3D sulfur host for lithium polysulfide adsorption-desorption and catalytic conversion in lithium-sulfur batteries

Abstract

The development of high activity electrocatalysts is considered effective strategy to improve the cathode kinetics in lithium-sulfur batteries (LSBs), especially those operating at high current densities and containing lean electrolytes. Herein, a nanostructured bimetallic sulfur cathode electrocatalyst containing p-block element indium, In/Co-NC, is prepared for the first time. This In-based proof of concept catalyst slows the conversion of elemental sulfur into soluble polysulfides (LiPS) while accelerating their bi-directional liquid-solid conversion, thus reducing their accumulation in the electrolyte and ultimately inhibiting the shuttle effect. LSB cells assembled using the newly prepared electrocatalyst demonstrated high cycle capability of more than 600 cycles at 3 C, accompanied by a high rate capability. Moreover, the In/Co-NC cell containing a lean electrolyte (E/S = 9 μL mgsulfur−1) exhibited 250 stable cycles at 0.5C with only 0.011% capacity decay per cycle. The study provides new design direction for cathode electrocatalysts and guidance for optimization of adsorption and catalytic processes in LSBs.