All-solid-state lithium-sulfur batteries(ASSLSBs)have become one of the most potential candidates for the next-generation high-energy systems due to their intrinsic safety and high theoretical energy density.However,PEO-based ASSLSBs face the dilemma of insufficient Coulombic efficiency and long-term stabil-ity caused by the coupling problems of dendrite growth of anode and polysulfide shuttle of cathode.In this work,1,3,5-trioxane(TOX)is used as a functional additive to design a PEO-based composite solid-state electrolyte(denoted as TOX-CSE),which realizes the stable long-term cycle of an ASSLSB.The results show that TOX can in-situ decompose on the anode to form a composite solid electrolyte inter-phase(SEI)layer with rich-organic component.It yields a high average modulus of 5.0 GPa,greatly improving the mechanical stability of the SEI layer and thus inhibiting the growth of dendrites.Also,the robust SEI layer can act as a barrier to block the side reaction between polysulfides and lithium metal.As a result,a Li-Li symmetric cell assembled with a TOX-CSE exhibits prolonged cycling stability over 2000 h at 0.2 mA cm-2.The ASSLSB also shows a stable cycling performance of 500 cycles at 0.5 C.This work reveals the structure-activity relationship between the mechanical property of interface layer and the battery's cycling stability.
Guangdong Provincial Key Laboratory of Fuel Cell Technology,School of Chemistry and Chemical Engineering South China University of Technology,Guangzhou 510640,Guangdong,China
Guangdong Provincial Research Center of Electrochemical Energy Engineering,South China University of Technology,Guangzhou 510640,Guangdong,China
School of Energy and Environment,City University of Hong Kong,Tat Chee Avenue,Kowloon,Hong Kong 999077,China
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