A cyano cobalt “electron transfer bridge” boosting the two-electron reaction of a MnO2 cathode with long lifespan in aqueous zinc batteries

Yaozhi Liu; Lu Lin; Tengsheng Zhang; Zhiqing Xue; Jie Liu; Dongliang Chao; Xiaoqi Sun

doi:10.1039/D3EE03711H

A cyano cobalt “electron transfer bridge” boosting the two-electron reaction of a MnO₂ cathode with long lifespan in aqueous zinc batteries†

Yaozhi Liu,^ab Lu Lin,^a Tengsheng Zhang,^b Zhiqing Xue,^a Jie Liu,^de Dongliang Chao

*^b and Xiaoqi Sun

*^ac

Author affiliations

* Corresponding authors

^a Department of Chemistry, Northeastern University, 3-11 Wenhua Road, Shenyang, China
E-mail: sunxiaoqi@mail.neu.edu.cn

^b Laboratory of Advanced Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, and School of Chemistry and Materials, Fudan University, Shanghai 200433, China
E-mail: chaod@fudan.edu.cn

^c National Frontiers Science Center for Industrial Intelligence and Systems Optimization, Northeastern University, 3-11 Wenhua Road, Shenyang, China

^d School of Resources and Civil Engineering, Northeastern University, 3-11 Wenhua Road, Shenyang, China

^e National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore Resources, Shenyang, China

Abstract

The dissolution/deposition reaction of MnO₂ cathode materials in aqueous zinc batteries provides two-electron transfers and delivers high theoretical capacity. However, this process usually requires an acidic environment and pre-added Mn²⁺ salts in electrolytes. Herein, we present an “electron transfer bridge” at the cathode to enhance the two-electron transfer contribution in MnO₂ in conventional zinc cells. A composite material with MnO₂ and CoO_x connected by Mn–N [triple bond, length as m-dash] C–Co interactions was synthesized. Mechanism studies demonstrate that the facile redox center of Co³⁺/Co²⁺ receives/donates electrons during discharge/charge processes, and electrons effectively transport to the Mn centers thanks to the narrowed band gap and charge delocalization. The dolosse-like hollow morphology formed through the inside-out Ostwald ripening process during the discharge further provides abundant reaction sites. These factors largely activate the dissolution/deposition process of MnO₂ material. In aqueous zinc cells with the conventional ZnSO₄ electrolyte, the composite cathode achieves a high capacity of 425 mA h g⁻¹ at 0.1 A g⁻¹, and an ultra-long life of over 25 000 cycles is realized at 2 A g⁻¹. This work presents an effective strategy to promote the high-capacity reaction path of MnO₂ in zinc batteries.

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Article information

DOI: https://doi.org/10.1039/D3EE03711H
Article type: Paper
Submitted: 31 Oct 2023
Accepted: 16 Feb 2024
First published: 01 Mar 2024

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Energy Environ. Sci., 2024,17, 2521-2529

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A cyano cobalt “electron transfer bridge” boosting the two-electron reaction of a MnO₂ cathode with long lifespan in aqueous zinc batteries

Y. Liu, L. Lin, T. Zhang, Z. Xue, J. Liu, D. Chao and X. Sun, Energy Environ. Sci., 2024, 17, 2521 DOI: 10.1039/D3EE03711H

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