Remarkable chemical adsorption and catalysis of monodisperse metallic cobalt sulfide nanoparticles enable long-cycling Li–S battery with high areal capacity and low shuttle constant

Abstract

High-energy density lithium-sulfur battery is considered as one of the most potential new-generation energy-storage technologies. Nevertheless, the capacity decays rapidly due to severe volumetric change of sulfur, dissolution and slow redox kinetics of intermediate polysulfides, and instability of lithium anode. Herein, a novel highly conductive porous sulfur cathode host composed of graphene aerogel and polar Co9S8 nanoparticle is designed to address these obstacles. The porous conductive framework not only provides channels for rapid conduction of electron and lithium ion, but also provides adequate space to physically confine the lithium polysulfides and accommodate the volume expansion. Both experimental and theoretical calculations demonstrate that the in-situ uniformly deposited Co9S8 nanoparticles can effectively bind polar lithium polysulfides and catalyze their interconversion, and the shuttle effect is therefore effectively suppressed. The Co9S8-GA/S cathode exhibits high specific discharge capacity (1219.1 mAh g−1) and high areal specific capacity (14.3 mAh m−2) at 0.1 C, low shuttle constant (0.15 h−1), excellent rate performance (625.6 mAh g−1/7.4 mAh m−2 at 5 C), outstanding long cyclic stability (low decay of 0.024 %/cycle during 1000 cycles at 2 C). This study demonstrates a promising aerogel strategy to design high-performance composite cathode for lithium-sulfur battery.