Chen Xiaojuan, Qin Lei, Sun Jiaonan, Zhang Songwei, Xiao Dan, Wu Yiying
College of Chemical Engineering, Sichuan University, Chengdu, 610065, P. R. China.
Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA.
Angew Chem Int Ed Engl. 2022 Aug 15;61(33):e202207018. doi: 10.1002/anie.202207018. Epub 2022 Jul 5.
Localized high-concentration electrolytes (LHCEs) have attracted interest in alkali metal batteries due to the advantages of forming stable solid-electrolyte interphases (SEIs) on anodes and good chemical/electrochemical stability. Herein, a new degradation mechanism is revealed for ether-based LHCEs that questions their compatibility with alkali metal anodes (Li, Na, and K). Specifically, the ether solvent reacts with alkali metals to generate solvated electrons (e ) that attack hydrofluoroether co-solvents to form a series of byproducts. The ether solvent essentially acts as a phase-transfer reagent that continuously transfers electrons from solid-phase metals into the solution phase, thus inhibiting the formation of stable SEI and leading to continuous alkali metal corrosion. Switching to an ester-based solvating solvent or intercalation anodes such as graphite or molybdenum disulfide has been shown to avoid such a degradation mechanism due to the absence of e .
局部高浓度电解质（LHCEs）因其在阳极上形成稳定的固体电解质界面（SEIs）以及良好的化学/电化学稳定性等优点，在碱金属电池领域引起了关注。在此，揭示了一种基于醚的LHCEs的新降解机制，该机制对其与碱金属阳极（锂、钠和钾）的兼容性提出了质疑。具体而言，醚溶剂与碱金属反应生成溶剂化电子（e ），这些电子攻击氢氟醚共溶剂形成一系列副产物。醚溶剂本质上充当相转移试剂，将电子从固相金属持续转移到溶液相中，从而抑制稳定SEI的形成并导致碱金属持续腐蚀。由于不存在e ，已证明切换到基于酯的溶剂化溶剂或插层阳极（如石墨或二硫化钼）可避免这种降解机制。
