Issue 7, 2023

Polyiodide shuttle inhibition in ethylene glycol-added aqueous electrolytes for high energy and long-term cyclability of zinc–iodine batteries

Abstract

Developing high-performance cathode materials matchable with zinc anodes is critical for the practical application of aqueous Zn metal batteries. Although cathodes based on iodine conversion chemistry are appealing owing to the high theoretical capacity and ideal redox potential of the I2/I redox couple compatible with water, they suffer from low coulombic efficiency and poor cycling stability because of the inevitable shuttle of polyiodides toward the Zn anodes and associated side reactions. Herein, high-density ordered porous graphene (HOPG) is utilized as the iodine host cathode in a ZnI2-containing aqueous electrolyte, achieving a high volumetric capacity of 388.8 mA h cm−3 at 1 A−1. Moreover, the shuttle of polyiodides and the side reactions on Zn anodes can be inhibited by adding ethylene glycol (EG) to the aqueous electrolyte, attributed to the complexation of EG with polyiodides and altered Zn2+ solvation structure. Consequently, the Zn–I2 battery exhibits a high energy density of 334.3 W h L−1 at 1.5 kW L−1 (based on the HOPG volume) and excellent cycling stability of 15 000 cycles with 97.6% capacity retention.

Graphical abstract: Polyiodide shuttle inhibition in ethylene glycol-added aqueous electrolytes for high energy and long-term cyclability of zinc–iodine batteries

Supplementary files

Article information

Article type
Paper
Submitted
01 Dec 2022
Accepted
16 Jan 2023
First published
17 Jan 2023

J. Mater. Chem. A, 2023,11, 3632-3639

Polyiodide shuttle inhibition in ethylene glycol-added aqueous electrolytes for high energy and long-term cyclability of zinc–iodine batteries

J. Zhang, Q. Dou, C. Yang, L. Zang and X. Yan, J. Mater. Chem. A, 2023, 11, 3632 DOI: 10.1039/D2TA09357J

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