Premature deposition of lithium polysulfide in lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries have attracted extensive attention due to ultrahigh theoretical energy density of 2600 Wh kg-1. Liquid-solid deposition from dissolved lithium polysulfides (LiPSs) to solid lithium sulfide (Li2S) largely determines the actual battery performances. Herein, a premature liquid- solid deposition process of LiPSs is revealed at higher thermodynamic potential than Li2S deposition in Li-S batteries. The premature solid deposit exhibits higher chemical state and hemispherical morphology in comparison with Li2S, and the premature deposition process is slower in kinetics and higher in depo-sition dimension. Accordingly, a supersaturation deposition mechanism is proposed to rationalize the above findings based on thermodynamic simulation. This work demonstrates a unique premature liq-uid-solid deposition process of Li-S batteries.(c) 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.