物理化学学报 >> 2022, Vol. 38 >> Issue (11): 2111003.doi: 10.3866/PKU.WHXB202111003

所属专题: 新锐科学家专刊

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水系锌二次电池MnO2正极的晶体结构、反应机理及其改性策略

陈鲜红1, 阮鹏超1, 吴贤文3, 梁叔全1,2, 周江1,2,*()   

  1. 1 中南大学材料科学与工程学院, 长沙 410083
    2 中南大学电子封装及先进功能材料湖南省重点实验室, 长沙 410083
    3 吉首大学化学化工学院, 湖南 吉首 416000
  • 收稿日期:2021-11-01 录用日期:2021-12-07 发布日期:2021-12-21
  • 通讯作者: 周江 E-mail:zhou_jiang@csu.edu.cn
  • 基金资助:
    湖南省杰出青年科学基金(2021JJ10064);湖南省湖湘英才人才支持计划(2020RC3011);国家自然科学基金(51932011);国家自然科学基金(51972346);国家自然科学基金(51872334);中南大学创新驱动项目(2020CX024)

Crystal Structures, Reaction Mechanisms, and Optimization Strategies of MnO2 Cathode for Aqueous Rechargeable Zinc Batteries

Xianhong Chen1, Pengchao Ruan1, Xianwen Wu3, Shuquan Liang1,2, Jiang Zhou1,2,*()   

  1. 1 School of Materials Science & Engineering, Central South University, Changsha 410083, China
    2 Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan Province, Central South University, Changsha 410083, China
    3 College of Chemistry and Chemical Engineering, Jishou University, Jishou 416000, Hunan Province, China
  • Received:2021-11-01 Accepted:2021-12-07 Published:2021-12-21
  • Contact: Jiang Zhou E-mail:zhou_jiang@csu.edu.cn
  • About author:Jiang Zhou, Email: zhou_jiang@csu.edu.cn
  • Supported by:
    the Hunan Outstanding Youth Talents(2021JJ10064);the Program of Youth Talent Support for Hunan Province(2020RC3011);the National Natural Science Foundation of China(51932011);the National Natural Science Foundation of China(51972346);the National Natural Science Foundation of China(51872334);the Innovation-Driven Project of Central South University(2020CX024)

摘要:

水系锌二次电池凭借其安全性高、环境友好、成本低廉、能量密度较高等诸多优势,有望应用于下一代大规模储能系统。电池的发展依赖于电极材料,二氧化锰由于其高丰度、低成本、毒性小等优势,在水系锌二次电池领域得到广泛应用。本文将从二氧化锰的晶体结构、反应机理及电化学性能出发,对其在水系锌二次电池中的研究进展进行系统综述。特别地,针对其容量低、循环稳定性差等问题,本文从储能机理(包括嵌入-脱嵌机制和溶解-沉积机制)角度出发,总结相对应的优化策略,为先进水系锌锰二次电池的设计开发提供参考。

关键词: 水系锌二次电池, 二氧化锰, 晶体结构, 反应机制, 优化策略

Abstract:

Because of the advantages of high safety, environment-friendliness, affordability, and ease of processing, aqueous rechargeable zinc batteries (ARZBs) are promising candidates for next-generation large-scale energy storage systems. In recent years, various cathode materials based on vanadium/manganese/cobalt oxides, Prussian blue analogs, and organic compounds have been reported. Among them, manganese dioxide (MnO2) is widely used in ARZBs due to their outstanding advantages of low toxicity, eco-friendliness, and high capacity (616 mAh∙g−1 based on two-electron transfer). However, the diversity of the crystal structures of MnO2 and the unpredictability of the electrochemical reaction make it difficult to investigate the specific internal storage mechanism, which impedes further development of the optimal modification strategies. To date, the main recognized energy storage mechanisms are (de)intercalation and dissolution-deposition mechanisms. In the traditional (de)intercalation mechanism, the predominant issues related to MnO2 during the cycling process include Mn dissolution, irreversible phase transformation, structural collapse, and sluggish ion diffusion kinetics. On the other hand, the detailed reaction path for the dissolution-deposition mechanism, which was developed in recent years, remains controversial. In addition, the incomplete dissolution-deposition of MnO2 and the highly acidic environment inevitably leads to corrosion and hydrogen evolution of the zinc anode, as well as low Coulombic efficiency. Accordingly, optimization strategies for different reaction mechanisms have been proposed to make zinc-manganese batteries more competitive. For the (de)intercalation mechanism, modification of composite materials and nanostructure optimization strategies can be adopted to inhibit the dissolution of MnO2 and increase the number of highly active reaction sites, thus enhancing the electrochemical performance. Moreover, the guest pre-intercalation strategy can help optimize the crystal structure of MnO2, preventing the collapse of the internal structure during cycling. Besides, defect engineering and element doping strategies focus on regulating the distribution of the electronic structure for affecting the properties of MnO2, resulting in lowering the energy barrier of zinc insertion. For the dissolution-deposition mechanism, the introduction of a neutral acetate and a halide mediator can effectively facilitate the dissolution-deposition of MnO2. Meanwhile, metal element catalysis can accelerate the reaction kinetics of the MnO2 dissolution-deposition, so that high-rate performance can be achieved. Furthermore, the decoupling battery system can separate the cathodic and anodic electrolytes to restrain the hydrogen and oxygen evolution reactions and enhance the potential difference. The flow battery system can effectively eliminate the influence of concentration polarization and stabilize the ion concentration in the electrolytes, thus leading to a large capacity (> 100 mAh). Undoubtedly, MnO2 as a high-capacity, high-voltage cathode material has broad development prospects for ARZBs. Here, we systematically summarize the crystal structures and reaction mechanisms of MnO2. We also discuss the optimization strategies toward advanced MnO2 cathode materials for resolving the highlighted issues in zinc-manganese batteries, which are expected to provide research directions for the design and development of high-performance ARZBs.

Key words: Aqueous rechargeable zinc battery, Manganese dioxide, Crystal structure, Reaction mechanism, Optimization strategy

MSC2000: 

  • O646