Issue 30, 2024

Enabling stable aqueous Zn metal anodes using scandium acetate electrolyte additives

Abstract

The potential of zinc metal anodes (ZMAs) for use in emerging aqueous electrochemical devices like rechargeable zinc-ion batteries and hybrid capacitors is substantial, owing to their high theoretical capacity, low redox potential, non-toxicity, abundant availability, and cost-effectiveness. However, the practical application of ZMAs faces limitations due to issues such as uncontrolled zinc dendrite growth and side reactions. In this study, we demonstrate that simultaneously incorporating scandium ions (Sc3+) and acetate anions (Ac) as electrolyte additives into a common ZnSO4 solution significantly enhances the cycling stability and reversibility of ZMAs. Our findings reveal that the Ac acts as a pH regulator, dynamically buffering the electrolyte pH to be around 4.3, effectively suppressing water-induced side reactions. Additionally, the synergistic effect of Sc3+ and Ac (Sc3+/Ac) facilitates the desolation process of Zn2+ and lowers the energy barrier for electrochemical Zn plating, resulting in uniform Zn plating without noticeable zinc dendrite growth. Consequently, Zn‖Zn symmetric cells utilizing the Sc3+/Ac electrolyte additive exhibit an ultra-long lifespan exceeding 1000 hours at 2.0 mA cm−2 and 1.0 mA h cm−2. Moreover, the Zn‖Cu cell demonstrates a high average coulombic efficiency of 99.4% after 400 plating/stripping cycles at 1.0 mA cm−2 and 1.0 mA h cm−2. Notably, when paired with an activated carbon (AC) cathode, Zn‖AC hybrid capacitors maintain a high-specific capacity of 62 mA h g−1 after 10 000 cycles at 1.0 A g−1. The research outcomes indicate that Sc3+ in combination with Ac are promising electrolyte additives for achieving highly stable aqueous ZMAs.

Graphical abstract: Enabling stable aqueous Zn metal anodes using scandium acetate electrolyte additives

Supplementary files

Article information

Article type
Paper
Submitted
31 Mar 2024
Accepted
10 Jun 2024
First published
11 Jun 2024

J. Mater. Chem. A, 2024,12, 18968-18976

Enabling stable aqueous Zn metal anodes using scandium acetate electrolyte additives

C. Chen, L. Li, Z. Long, E. H. Ang and Q. Liang, J. Mater. Chem. A, 2024, 12, 18968 DOI: 10.1039/D4TA02133A

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