Kinetics Conditioning of (Electro) Chemically Stable Zn Anode with pH Regulation Toward Long-Life Zn-Storage Devices

Yalan Guo; Zhengang Li; Ben Niu; Heng Chen; Yu Qiao; Yulin Min; Xin Wang

doi:10.1002/smll.202310341

Kinetics Conditioning of (Electro) Chemically Stable Zn Anode with pH Regulation Toward Long-Life Zn-Storage Devices

Small. 2024 Jan 15:e2310341. doi: 10.1002/smll.202310341. Online ahead of print.

Authors

Yalan Guo^{1

2}, Zhengang Li³, Ben Niu¹, Heng Chen^{1

4}, Yu Qiao³, Yulin Min², Xin Wang¹

Affiliations

¹ Songshan Lake Materials Laboratory, Dongguan, 523808, China.
² Shanghai Key Laboratory of Materials Protection and Advanced Materials Electric Power, Shanghai Engineering Research Center of Energy-Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai, 200090, China.
³ State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
⁴ Research Institute of Interdisciplinary Science & School of Materials Science and Engineering, Dongguan University of Technology, Dongguan, 523808, China.

PMID: 38225705
DOI: 10.1002/smll.202310341

Abstract

The safety, low cost, and high power density of aqueous Zn-based devices (AZDs) appeal to large-scale energy storage. Yet, the presence of hydrogen evolution reaction (HER) and chemical corrosion in the AZDs leads to local OH^- concentration increasement and the formation of Zn_x SO_y (OH)_z •nH₂ O (ZHS) by-products at the Zn/electrolyte interface, causing instability and irreversibility of the Zn-anodes. Here, a strategy is proposed to regulate OH^- by introducing a bio-sourced/renewable polypeptide (ɛ-PL) as a pH regulator in electrolyte. The consumption of OH^- species is evaluated through in vitro titration and cell in vivo in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy at a macroscopic and molecular level. The introduction of ɛ-PL is found to significantly suppress the formation of ZHS and associated side reactions, and reduce the local coordinated H₂ O of the Zn²⁺ solvation shell, widening electrochemical stable window and suppressing OH^- generation during HER. As a result, the inclusion of ɛ-PL improves the cycle time of Zn/Zn symmetrical cells from 15 to 225 h and enhances the cycle time of aqueous Zn- I₂ cells to 1650 h compared to those with pristine electrolytes. This work highlights the potential of kinetical OH^- regulation for by-product and dendrite-free AZDs.

Keywords: OH−-regulation; Zn corrosion; Zn-metal anode; aqueous Zn batteries; ɛ-PL additive.

Abstract

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