Toward a Reversible Mn⁴⁺/Mn²⁺ Redox Reaction and Dendrite-Free Zn Anode in Near-Neutral Aqueous Zn/MnO2 Batteries via Salt Anion Chemistry

Authors

Xiaohui Zeng, University of WollongongFollow
Jiatu Liu
Jianfeng Mao, University of WollongongFollow
Junnan Hao, University of WollongongFollow
Zhijie Wang, University of WollongongFollow
Si Zhou, University of WollongongFollow
Chris Ling
Zaiping Guo, University of WollongongFollow

RIS ID

144243

Publication Details

Zeng, X., Liu, J., Mao, J., Hao, J., Wang, Z., Zhou, S., Ling, C. & Guo, Z. (2020). Toward a Reversible Mn⁴⁺/Mn²⁺ Redox Reaction and Dendrite-Free Zn Anode in Near-Neutral Aqueous Zn/MnO2 Batteries via Salt Anion Chemistry. Advanced Energy Materials,

Abstract

© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Rechargeable aqueous Zn/MnO2 batteries are very attractive large-scale energy storage technologies, but still suffer from limited cycle life and low capacity. Here the novel adoption of a near-neutral acetate-based electrolyte (pH ≈ 6) is presented to promote the two-electron Mn4+/Mn2+ redox reaction and simultaneously enable a stable Zn anode. The acetate anion triggers a highly reversible MnO2/Mn2+ reaction, which ensures high capacity and avoids the issue of structural collapse of MnO2. Meanwhile, the anode-friendly electrolyte enables a dendrite-free Zn anode with outstanding stability and high plating/stripping Coulombic efficiency (99.8%). Hence, a high capacity of 556 mA h g−1, a lifetime of 4000 cycles without decay, and excellent rate capability up to 70 mA cm−2 are demonstated in this new near-neutral aqueous Zn/MnO2 battery by simply manipulating the salt anion in the electrolyte. The acetate anion not only modifies the surface properties of MnO2 cathode but also creates a highly compatible environment for the Zn anode. This work provides a new opportunity for developing high-performance Zn/MnO2 and other aqueous batteries based on the salt anion chemistry.