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

Liyang Liu; Haiying Lu; Chao Han; Xianfei Chen; Sucheng Liu; Jiakui Zhang; Xianghong Chen; Xinyi Wang; Rui Wang; Jiantie Xu; Hua Kun Liu; Shi Xue Dou; Weijie Li

doi:10.1021/acsnano.3c08716

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

ACS Nano. 2023 Nov 28;17(22):23065-23078. doi: 10.1021/acsnano.3c08716. Epub 2023 Nov 10.

Authors

Liyang Liu^{1

2

3}, Haiying Lu², Chao Han⁴, Xianfei Chen⁵, Sucheng Liu², Jiakui Zhang², Xianghong Chen², Xinyi Wang³, Rui Wang², Jiantie Xu², Hua Kun Liu^{3

6}, Shi Xue Dou^{3

6}, Weijie Li^{1

3}

Affiliations

¹ State Key Laboratory for Powder Metallurgy, Central South University, Changsha, 410083, China.
² Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, School of Environment and Energy, South China University of Technology, Guangzhou, 510640, China.
³ Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, Wollongong, 2522, Australia.
⁴ School of Materials Science and Engineering, Central South University, Changsha, 410083, China.
⁵ College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu, 610059, China.
⁶ Institute of Energy Materials Science, University of Shanghai for Science and Technology, Shanghai, 200093, China.

PMID: 37948160
DOI: 10.1021/acsnano.3c08716

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.

Keywords: amphiphilicity; aqueous zinc batteries; core−shell solvation structure; cosolvent selection strategy; salt anion.