Engineering Pt heterogeneous catalysts for accelerated liquid-solid redox conversion in Li-S batteries

The shuttle effect caused by soluble lithium polysulfides (LiPSs) deteriorates multiphase transformation reaction kinetics of sulfur species, and gives rise to an unserviceable lithium-sulfur (Li-S) battery. Catalysis, as a process optimization approach, offers an option to eliminate the intrinsic issues. However, exploring and understanding the role of catalysts on electrode reaction remains critical bottle-necks, particularly as they are prone to continuous evolution under complex dynamic environment. Herein, platinum nanoparticles loaded on MXene nanosheets, as sulfur host, and the action of catalysts on the reaction process are investigated via ex-situ monitors upon solid-liquid-solid chemical transformation of sulfur species. These traces confirm that the high performance originates from electron transfer between catalysts and LiPSs, which lowers the nucleation barrier from liquid LiPSs to solid Li2S/Li2S2. Further, the accelerated liquid-solid conversion can alleviate the accumulation of LiPSs, and boost the reaction kinetics in Li-S batteries. The findings corroborate the electronic modulation between catalysts and LiPSs, which is a generalizable strategy to optimize energy conversion efficiency of Li-S batteries. (C) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.