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Aqueous eutectic electrolytes suppress oxygen and hydrogen evolution for long-life Zn||MnO2 dual-electrode-free batteries

Nature Energy volume 11, pages 299–312 (2026) Cite this article

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Abstract

Aqueous Zn2+/Zn||MnO2/Mn2+ batteries—operating via electrodeposition/dissolution—offer promising high-voltage, high-capacity grid-storage capabilities but require acidic conditions for MnO2/Mn2+ conversion, and these induce problematic zinc corrosion. Here we present a global approach that identifies deep eutectic aqueous–organic electrolytes that strategically disrupt water’s hydrogen-bonding network, simultaneously enhancing MnO2 reversibility at the cathode while enabling stable zinc cycling at the anode without water decomposition. Such non-flammable electrolytes regulate the cation solvation structure and phase of the deposited MnO2 and its morphology, promoting layered structures with enhanced ion-transport pathways that significantly improve stripping efficiency. These deep eutectics increase the oxygen evolution overpotential well above the MnO2 deposition potential, which completely suppresses unwanted O2 evolution. Moreover, they alter the local environment at the cathode interface to create localized interfacial pH gradients that influence critical processes, including optimizing proton transport and MnO2 stripping. Our Zn2+/Zn||MnO2/Mn2+ dual-electrode-free battery achieves high Coulombic efficiency for extended cycling (>5,000 cycles) without external acid addition, advancing high-energy-density zinc–manganese battery development through rational electrolyte design.

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Fig. 1: Schematic representation of a Zn2+/Zn||MnO2/Mn2+ battery.
The alternative text for this image may have been generated using AI.
Fig. 2: Electrochemical performance of the Zn2+/Zn||MnO2/Mn2+ full cell.
The alternative text for this image may have been generated using AI.
Fig. 3: Characterization of the deposition product on the cathode.
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Fig. 4: Differences of MnO2 morphology in different electrolytes.
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Fig. 5: Cationic solvation structure.
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Fig. 6: Reversibility of MnO2 deposition and dissolution.
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Fig. 7: pH and gas evolution during cycling.
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Fig. 8: Deposition morphology and electrochemical performance of the anode.
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Data availability

All relevant data that support the findings of this study are presented in the Article and its Supplementary Information.

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Acknowledgements

This work was supported by the NSERC through funds to L.F.N. via the Discovery Grant and Canada Research Chair programmes. Modelling at ARL was supported by the US Department of Energy via SN2020957. We thank the Aqueous Battery Consortium (ABC) for inspiration for this work, and Z. Yu, and Y. Wang for assistance with the DSC and XRD measurements. We appreciate valuable discussions held with V. Augustyn, R. Clement and T. P. Pollard during the course of the work.

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Author notes

  1. These authors contributed equally: Jinghan Li, Chang Li.

Authors and Affiliations

  1. Department of Chemistry and the Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario, Canada

    Jinghan Li, Chang Li & Linda F. Nazar

  2. Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA

    Bo Liu & Yuzhang Li

  3. Battery Science Branch, Energy Sciences Division, DEVCOM Army Research Laboratory, Adelphi, MD, USA

    Oleg Borodin

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  1. Jinghan Li
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  2. Chang Li
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Contributions

C.L. and L.F.N. designed this study. J.L. carried out the characterization and all the electrochemical measurements. B.L. performed TEM and STEM-EDS studies. Y.L. supervised the TEM studies. O.B. performed DFT calculations and MD simulations. J.L., C.L. and L.F.N. wrote the manuscript with contributions from other authors.

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Correspondence to Chang Li or Linda F. Nazar.

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Nature Energy thanks Christel Laberty-Robert, Jinwoo Lee and Yuqi Li for their contribution to the peer review of this work.

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Supplementary Note 1, Supplementary Figs. 1–31, Supplementary Tables 1–4 and Supplementary References.

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The flammability test shows non-flammability of the SL/DMSO ternary electrolyte.

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Li, J., Li, C., Liu, B. et al. Aqueous eutectic electrolytes suppress oxygen and hydrogen evolution for long-life Zn||MnO2 dual-electrode-free batteries. Nat Energy 11, 299–312 (2026). https://doi.org/10.1038/s41560-025-01958-8

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