Salt Anion Amphiphilicity-Activated Electrolyte Cosolvent Selection Strategy toward Durable Zn Metal Anode

作者：Liyang Liu, Haiying Lu, Chao Han, Xianfei Chen, Sucheng Liu, Jiakui Zhang, Xianghong Chen, Xinyi Wang, Rui Wang, Jiantie Xu, Huan Liu, Shi Xue Dou, Weijie Li · 发表于：ACS Nano · 年份：2023 · DOI：10.1021/acsnano.3c08716 · 被引用次数：107 · 研究领域：Advanced battery technologies research、Advanced Battery Materials and Technologies、Perovskite Materials and Applications

One effective solution to inhibit side reactions and Zn dendrite growth in aqueous Zn-ion batteries is to add a cosolvent into the Zn(CF 3 SO 3 ) 2 electrolyte, which has the potential to form a robust solid electrolyte interface composed of ZnF 2 and ZnS. Nevertheless, there is still a lack of discussion on a convenient selection method for cosolvents, which can directly reflect the interactions between solvent and solute to rationally design the electrolyte solvation structure. Herein, log P, where P is the octanol–water partition coefficient, a general parameter to describe the hydrophilicity and lipophilicity of chemicals, is proposed as a standard for selecting cosolvents for Zn(CF 3 SO 3 ) 2 electrolyte, which is demonstrated by testing seven different types of solvents. The solvent with a log P value similar to that of the salt anion CF 3 SO 3 – can interact with CF 3 SO 3 –, Zn 2+, and H 2 O, leading to a reconstruction of the electrolyte solvation structure. To prove the concept, methyl acetate (MA) is demonstrated as an example due to its similar log P value to that of CF 3 SO 3 – . Both the experimental and theoretical results illustrate that MA molecules not only enter into the solvation shell of CF 3 SO 3 – but also coordinate with Zn 2+ or H 2 O, forming an MA and CF 3 SO 3 – involved core–shell solvation structure. The special solvation structure reduces H 2 O activity and contributes to forming an anion-induced ZnCO 3 –ZnF 2 -rich solid electrolyte interface. ...