Xing Fei, Fu Qiang, Xing Feng, Zhao Jian, Long Haoyang, Liu Tao, Li Xianfeng
Division of Energy Storage, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
J Am Chem Soc. 2024 Sep 25;146(38):26024-26033. doi: 10.1021/jacs.4c04951. Epub 2024 Sep 16.
Vanadium flow batteries (VFBs) are considered one of the most promising candidates for large-scale energy storage. However, VFBs suffer from relatively low power density due to severe electrochemical polarization. Herein, we report Bi single atoms supported by an N-doped carbon-regulated graphite felt electrode (Bi SAs/NC@GF) with high electrocatalytic activity and stability, owing to the greatly improved active sites and optimized Bi-N configuration. Electrochemical in situ characterization and theoretical calculations elucidate the desolvation process and specific inner sphere reaction mechanism of [V(HO)]/[V(HO)]. As a result, a VFB single cell assembled with Bi SAs/NC@GF achieves a much higher energy efficiency of 81.1% at 240 mA cm than NC@GF (70.5%). Moreover, a 5 kW VFB stack equipped with Bi SAs/NC@GF is assembled for the first time and ran stably for over 400 cycles. This work confirms that a single-atom catalyst is efficient for scalable VFBs with high power density and low cost.
钒液流电池（VFBs）被认为是大规模储能最有前景的候选者之一。然而，由于严重的电化学极化，钒液流电池的功率密度相对较低。在此，我们报道了一种由氮掺杂碳调控的石墨毡电极负载的铋单原子（Bi SAs/NC@GF），由于活性位点的大幅改善和铋 - 氮构型的优化，该电极具有高电催化活性和稳定性。电化学原位表征和理论计算阐明了[V(HO)]/[V(HO)]的去溶剂化过程和特定的内球反应机理。结果，与NC@GF（70.5%）相比，采用Bi SAs/NC@GF组装的钒液流电池单电池在240 mA cm时实现了更高的81.1%的能量效率。此外，首次组装了配备Bi SAs/NC@GF的5 kW钒液流电池堆，并稳定运行了400多个循环。这项工作证实了单原子催化剂对于具有高功率密度和低成本的可扩展钒液流电池是有效的。
