Six-Electron-Conversion Selenium Cathodes Stabilized by Dead-Selenium Revitalizer for Aqueous Zinc Batteries

Schematic showing the configuration of the Zn||Se cells. a Zn||Se cell with ZCE (30 m ZnCl₂ hydrogel electrolyte), in which rapid performance decay is caused by the formation of dead Se on Zn anode. b Zn||Se cell with ZCE-Br (30 m ZnCl₂ hydrogel electrolyte with bromide salt additive), in which the Br⁻/Br_n⁻ redox couple serves as a dead Se revitalizer and stabilizes the Se electrode performance.

Aqueous zinc batteries (AZBs) are attractive for large-scale energy storage due to their inherent safety and sustainability. However, their widespread application has been constrained by limited energy density, underscoring a high demand of advanced cathodes with large capacity and high redox potential. Here, we report a reversible high-capacity six-electron-conversion Se cathode undergoing a ZnSe↔Se↔SeCl₄ reaction, with Br⁻/Br_n⁻ redox couple effectively stabilizes the Zn||Se cell. This Se conversion, initiated in a ZnCl₂­-based hydrogel electrolyte, presents rapid capacity decay (from 1937.3 to 394.1 mAh g_Se⁻¹ after only 50 cycles at 0.5 A g_Se⁻¹) primarily due to the dissolution of SeCl₄ and its subsequent migration to the Zn anode, resulting in dead Se passivation. To address this, we incorporate the Br⁻/Br_n⁻ redox couple into the Zn||Se cell by introducing bromide salt as an electrolyte additive. The generated Br_n⁻ species acts as a dead-Se revitalizer by reacting with Se passivation on the Zn anode and regenerating active Se for the cathode reaction. Consequently, the cycling stability of the Zn||Se cell is improved, maintaining 1246.8 mAh g_Se⁻¹ after 50 cycles. Moreover, the Zn||Se cell exhibits a specific capacity of 2077.6 mAh g_Se⁻¹ and specific energy of 404.2 Wh kg⁻¹ based on the overall cell reaction, making it a promising AZB configuration for high-energy purposes. Additionally, this study establishes the concept of dead-material revitalizer as a promising approach for stabilizing conversion-type battery electrodes.

Reference: Jingwei Du, Jiaxu Zhang, Xingyuan Chu, Hao Xu, Yirong Zhao, Markus Löffler, Gang Wang, Dongqi Li, Quanquan Guo, Ahiud Morag, Jie Du, Jianxin Zou, Daria Mikhailova, Vlastimil Mazánek, Zdeněk Sofer, Xinliang Feng*, Minghao Yu*. Six-electron-conversion selenium cathodes stabilized by dead-selenium revitalizer for aqueous zinc batteries. Nat. Commun. 16, 3707 (2025). https://doi.org/10.1038/s41467-025-58859-3

Acknowledgements: This work was financially supported by European Union’s Horizon 2020 research and innovation programme (LIGHT-CAP 101017821), and Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), CRC1415 (Grant No. 417590517). J. D., J. Z., D. L., and X. C. thank China Scholarship Council for financial support. V.M. was supported by project LUAUS23049 from Ministry of Education Youth and Sports (MEYS). Z.S. was supported by ERC-CZ program (project LL2101) from Ministry of Education Youth and Sports (MEYS) and by the project Advanced Functional Nanorobots (reg. No. CZ.02.1.01/0.0/0.0/15_003/0000444 financed by the ERDF). The authors acknowledge the use of the facilities in the Dresden Center for Nanoanalysis (DCN) at Technische Universität Dresden, the GWK support for providing computing time through the Center for Information Services and High-Performance Computing (ZIH) at TU Dresden, and beam time allocation at beamline P65 at the PETRA III synchrotron (DESY, Hamburg, Germany) and beamline BM23 at ESRF synchrotron (Grenoble, France).