Advances in Aqueous Electrolyte Engineering: From Fundamental Limitations to Emerging Strategies
- 1School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng 224051, China
- 2Jiangsu Key Laboratory of Coastal Photovoltaic Technology and System, Yancheng Institute of Technology, Yancheng 224051, China
Abstract
Aqueous rechargeable batteries are promising candidates for large-scale energy storage owing to their inherent safety, low cost, and environmental compatibility, yet the narrow 1.23 V electrochemical stability window (ESW) of water limits their energy density. Since the seminal 2015 report of water-in-salt electrolytes (WiSE), electrolyte engineering—manipulating the molecular environment of water, including its O–H bond strength, hydrogen-bond topology, and interfacial reactivity—has emerged as the central strategy for overcoming this thermodynamic constraint. This review synthesizes the representative studies across Li+, Na+, K+, and Zn2+ chemistries into a unified framework that links the physicochemical fundamentals of aqueous electrolytes (ion solvation, hydrogen-bond networks, the electrical double layer, and ion transport) with five classes of strategies—concentration, solvation-structure, and interface engineering; emerging electrolyte systems (deep eutectic, ionic-liquid–water, asymmetric decoupled, gel, and high-entropy); and practical challenges (wide-temperature operation, cost, and scalability). Examining unresolved controversies—the thermodynamic versus kinetic origin of ESW expansion in WiSE, the long-term chemical persistence of aqueous solid electrolyte interphases, and the definitional boundary of aqueous batteries—this review proposes a research roadmap spanning multi-strategy orthogonal integration and standardized evaluation protocols, providing both a tutorial for newcomers and a critical reference for researchers pursuing practical high-voltage aqueous batteries.
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BibTeX
@article{sun2026advances,
title = {{Advances in Aqueous Electrolyte Engineering: From Fundamental Limitations to Emerging Strategies}},
author = {Yong-Gang Sun and Yi-Han Zhang and Jian Xiong and Jin-Yi Ding and Yu Hu and Xin Wang and Jun-Yu Zhao and Hao-Jie Fan and Song Chen},
journal = {Molecules},
year = {2026},
month = oct,
doi = {10.3390/molecules31203721},
url = {https://www.mdpi.com/1420-3049/31/20/3721},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Advances in Aqueous Electrolyte Engineering: From Fundamental Limitations to Emerging Strategies
AU - Yong-Gang Sun
AU - Yi-Han Zhang
AU - Jian Xiong
AU - Jin-Yi Ding
AU - Yu Hu
AU - Xin Wang
AU - Jun-Yu Zhao
AU - Hao-Jie Fan
AU - Song Chen
PY - 2026
DA - 2026/10/01
JO - Molecules
DO - 10.3390/molecules31203721
UR - https://www.mdpi.com/1420-3049/31/20/3721
AB - Aqueous rechargeable batteries are promising candidates for large-scale energy storage owing to their inherent safety, low cost, and environmental compatibility, yet the narrow 1.23 V electrochemical stability window (ESW) of water limits their energy density. Since the seminal 2015 report of water-in-salt electrolytes (WiSE), electrolyte engineering—manipulating the molecular environment of water, including its O–H bond strength, hydrogen-bond topology, and interfacial reactivity—has emerged as the central strategy for overcoming this thermodynamic constraint. This review synthesizes the representative studies across Li+, Na+, K+, and Zn2+ chemistries into a unified framework that links the physicochemical fundamentals of aqueous electrolytes (ion solvation, hydrogen-bond networks, the electrical double layer, and ion transport) with five classes of strategies—concentration, solvation-structure, and interface engineering; emerging electrolyte systems (deep eutectic, ionic-liquid–water, asymmetric decoupled, gel, and high-entropy); and practical challenges (wide-temperature operation, cost, and scalability). Examining unresolved controversies—the thermodynamic versus kinetic origin of ESW expansion in WiSE, the long-term chemical persistence of aqueous solid electrolyte interphases, and the definitional boundary of aqueous batteries—this review proposes a research roadmap spanning multi-strategy orthogonal integration and standardized evaluation protocols, providing both a tutorial for newcomers and a critical reference for researchers pursuing practical high-voltage aqueous batteries.
SN - 1420-3049
ER -