Poly(ethylene)oxide(PEO)-based electrolytes have been widely studied for solid-state lithium batteries while their ionic conductivity and lithium-ion transference number still need to be further improved.Herein,using the combined experimental and theoretical approach,we demonstrate a novel,solid-state PEO-deep eutectic solvent(DES)electrolyte for the first time.We found that the in situ formation of DES can reduce the crystallinity of PEO matrix and more Li+ions can move freely owing to the weak-ened coordination between ether oxygens and Li-ions.Besides,we show that more Li+ions can be disso-ciated from Li salts in PEO-DES electrolyte using the molecular dynamics simulations.Such liquid-free PEO-DES electrolytes showed good ionic conductivity(2.1×10-4 S cm-1)which is 160％higher than that of conventional PEO-LiTFSI(8.1×10-5 S cm-1)electrolyte at 60℃.Additionally,the PEO-DES electrolyte showed 136％increase of Li-ion transference number(0.33)compared with ionic liquid-doped PEO-LiTFSI(0.14)at 60℃.Moreover,the PEO-DES exhibited good compatibility with Li metal and stable Li plating/stripping behavior with little morphology change of Li metal.This research also provides new insights into the enhancement mechanisms of novel polymer electrolytes,improving our fundamental under-standing of critical challenges that have impeded the adoption of solid-state lithium metal batteries.

School of Mechanical and Materials Engineering,Washington State University,Pullman,WA 99164,United States;Materials Sciences,Pacific Northwest National Laboratory,Richland,WA 99352,United States

[1]Panpan Dong;Xiahui Zhang;Kee Sung Han;Younghwan Cha;Min-Kyu Song-.Deep eutectic solvent-based polymer electrolyte for solid-state lithium metal batteries)[J].能源化学,2022(07):363-372

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