Xiao Neng, Gourdin Gerald, Wu Yiying
Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA.
Angew Chem Int Ed Engl. 2018 Aug 20;57(34):10864-10867. doi: 10.1002/anie.201804115. Epub 2018 Jun 19.
In superoxide batteries based on O /O redox chemistry, identifying an electrolyte to stabilize both the alkali metal and its superoxide remains challenging owing to their reactivity towards the electrolyte components. Bis(fluorosulfonyl)imide (FSI ) has been recognized as a "magic anion" for passivating alkali metals. The KFSI-dimethoxyethane electrolyte passivates the potassium metal anode by cleavage of S-F bonds and the formation of a KF-rich solid-electrolyte interphase (SEI). However, the KFSI salt is chemically unstable owing to nucleophilic attack by superoxide and/or hydroxide species. On the other hand, potassium bis(trifluorosulfonyl)imide (KTFSI) is stable to KO , but results in mossy potassium deposits and irreversible plating and stripping. To circumvent this dilemma, we developed an artificial SEI for the metal anode and thus long-cycle-life K-O batteries. This study will guide the development of stable electrolytes and artificial SEIs for metal-O batteries.
在基于O₂/O₂⁻氧化还原化学的超氧化物电池中，由于碱金属及其超氧化物对电解质成分具有反应活性，因此找到一种能同时稳定碱金属及其超氧化物的电解质仍然具有挑战性。双（氟磺酰）亚胺（FSI⁻）已被认为是一种钝化碱金属的“神奇阴离子”。KFSI-二甲氧基乙烷电解质通过S-F键的断裂和富含KF的固体电解质界面（SEI）的形成来钝化钾金属阳极。然而，由于超氧化物和/或氢氧化物物种的亲核攻击，KFSI盐在化学上不稳定。另一方面，双（三氟磺酰）亚胺钾（KTFSI）对超氧化钾稳定，但会导致苔藓状钾沉积以及不可逆的镀覆和剥离。为了克服这一困境，我们开发了一种用于金属阳极的人工SEI，从而实现了长循环寿命的K-O₂电池。这项研究将指导金属-O₂电池稳定电解质和人工SEI的开发。
