How Water Accelerates Bivalent Ion Diffusion at the Electrolyte/Electrode Interface

• Published in: Angewandte Chemie (International ed.) Vol. 57; no. 37; pp. 11978 - 11981
• Main Authors: Wang, Fei, Sun, Wei, Shadike, Zulipiya, Hu, Enyuan, Ji, Xiao, Gao, Tao, Yang, Xiao‐Qing, Xu, Kang, Wang, Chunsheng
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 10-09-2018; Wiley
• Edition: International ed. in English
• Subjects: batteries; Charge transport; electrochemistry; Electrodes; Electrolytes; ENERGY STORAGE; Groundwater flow; Ion diffusion; Kinetics; Lattices; Organic chemistry; Reaction kinetics; water; Water activity; Water discharge; Zinc; electrochemistry; electrolytes; kinetics; batteries; water
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201806748

The effect of H2O in electrolytes and in electrode lattices on the thermodynamics and kinetics of reversible multivalent‐ion intercalation chemistry based on a model platform of layered VOPO4 has been investigated. The presence of H2O at the electrolyte/electrode interface plays a key role in assisting Zn2+ diffusion from electrolyte to the surface, while H2O in the lattice structure alters the working potential. More importantly, a dynamic equilibrium between bulk electrode and electrolyte is eventually reached for H2O transport during the charge/discharge cycles, with the water activity serving as the key parameter determining the direction of water movement and the cycling stability.
Water of life: H2O at the electrolyte/electrode interface plays a key role in assisting Zn2+ diffusion from electrolytes to the bulk surface, while H2O in the lattice structure alters the working potential. A dynamic equilibrium between the bulk electrode and electrolyte is eventually established for H2O transport during the charge/discharge cycles.