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

Authors

Liyang Liu, Central South University
Haiying Lu, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control
Chao Han, Central South University
Xianfei Chen, Chengdu University of Technology
Sucheng Liu, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control
Jiakui Zhang, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control
Xianghong Chen, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control
Xinyi Wang, University of Wollongong
Rui Wang, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control
Jiantie Xu, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control
Hua Kun Liu, University of Wollongong
Shi Xue Dou, University of Wollongong
Weijie Li, Central South University

Publication Name

ACS Nano

Abstract

One effective solution to inhibit side reactions and Zn dendrite growth in aqueous Zn-ion batteries is to add a cosolvent into the Zn(CF3SO3)2 electrolyte, which has the potential to form a robust solid electrolyte interface composed of ZnF2 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, logP, 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(CF3SO3)2 electrolyte, which is demonstrated by testing seven different types of solvents. The solvent with a logP value similar to that of the salt anion CF3SO3- can interact with CF3SO3-, Zn2+, and H2O, 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 logP value to that of CF3SO3-. Both the experimental and theoretical results illustrate that MA molecules not only enter into the solvation shell of CF3SO3- but also coordinate with Zn2+ or H2O, forming an MA and CF3SO3- involved core-shell solvation structure. The special solvation structure reduces H2O activity and contributes to forming an anion-induced ZnCO3-ZnF2-rich solid electrolyte interface. As a result, the Zn||Zn cell and Zn||NaV3O8·1.5H2O cell with MA-involved electrolyte exhibit superior performances to that with the MA-free electrolyte. This work provides an insight into electrolyte design via salt anion chemistry for high-performance Zn batteries.

Open Access Status

This publication is not available as open access

Volume

17

Issue

22

First Page

23065

Last Page

23078

Funding Number

2019ZT08L075

Funding Sponsor

Guangdong Innovative and Entrepreneurial Research Team Program