Huangyang Xiaoyi, Wang Hongrui, Zhou Weibin, Deng Qi, Liu Zhuo, Zeng Xian-Xiang, Wu Xiongwei, Ling Wei
School of Chemistry and Materials Science, Hunan Agricultural University, Changsha 410128, P. R. China.
Hunan Key Laboratory of Extreme Matter and Applications, National University of Defense Technology, Changsha 410073, P. R. China.
ACS Appl Mater Interfaces. 2024 Jun 26;16(25):32189-32197. doi: 10.1021/acsami.4c02971. Epub 2024 Jun 13.
Owing to the advantages of low cost, high safety, and a desirable cycling lifetime, vanadium redox flow batteries (VRFBs) have attracted great attention in the large-scale energy storage field. However, graphite felts (GFs), widely used as electrode materials, usually possess an inferior catalytic activity for the redox reaction of vanadium ions, largely limiting the energy efficiency and rate performance of VRFBs. Here, an in situ growth of amorphous MnO on graphite felt (AMO@GF) was designed for application in VRFBs via mild and rapid etching engineering (5 min). After the etching process, the graphite felt fibers showed a porous and defective surface, contributing to abundant active sites toward the redox reaction. In addition, formed amorphous MnO can also serve as a powerful catalyst to facilitate the redox couples of VO/VO based on density functional theoretical (DFT) calculations. As a result, the VRFB using AMO@GF displayed an elevated energy efficiency and superior stability after 2400 cycles at 200 mA cm, and the maximum current density can reach 300 mA cm. Such a high-efficiency and convenient design strategy for the electrode material will drive the further development and industrial application of VRFBs and other flow battery systems.
由于具有低成本、高安全性和良好循环寿命等优点，钒氧化还原液流电池（VRFBs）在大规模储能领域引起了极大关注。然而，广泛用作电极材料的石墨毡（GFs）对钒离子的氧化还原反应通常具有较差的催化活性，这在很大程度上限制了VRFBs的能量效率和倍率性能。在此，通过温和快速的蚀刻工程（5分钟）设计了一种在石墨毡上原位生长非晶态MnO的方法（AMO@GF），用于VRFBs。蚀刻过程后，石墨毡纤维呈现出多孔且有缺陷的表面，为氧化还原反应提供了丰富的活性位点。此外，基于密度泛函理论（DFT）计算，形成的非晶态MnO还可以作为一种强大的催化剂来促进VO/VO的氧化还原对。结果，使用AMO@GF的VRFB在200 mA cm下经过2400次循环后显示出提高的能量效率和优异的稳定性，最大电流密度可达300 mA cm。这种用于电极材料的高效便捷设计策略将推动VRFBs和其他液流电池系统的进一步发展和工业应用。
