In this paper, the SiO₂-decorated graphite felts are obtained by silicic acid etching graphite felts in hot air, and their performance as the electrodes of iron-chromium redox flow battery (ICRFB) is investigated. The surface morphology, microstructure and surface chemical composition of SiO₂-decorated graphite felts are characterized in detail through scanning electron microscopy, specific surface area analysis, X-ray Photoelectron Spectroscopy, X-ray diffraction, and Raman Spectroscopy. The electrocatalytic activity of SiO₂-decorated graphite felts and the performance in ICRFBs are studied by electrochemical impedance spectroscopy, cyclic voltammetry, and single-cell charge-discharge cycling tests. Results indicate that the SiO₂ introduced by the decomposition of silicic acid can increase the effective specific surface area of the graphite felts, and concurrently facilitate the oxidation of the SiO₂-decorated graphite felts in hot air. The number of oxygen functional groups and the defect sites on the surface of the SiO₂-decorated graphite felts increase to a great degree that especially have a considerable influence on the negative reaction activity of the ICRFB. An ICRFB assembled with graphite felts etched by 50 wt% silicic acid as the electrodes has a voltage efficiency and energy efficiency of 86.27% and 79.66% at a current density of 120 mA/cm² respectively. The decay rate of capacity is only 0.46% per cycle. The cost-effective and convenient method demonstrated in this paper can coordinate the control of oxygen functional groups, surface area and electrical conductivity of graphite felts, which may provide an example for improving the electrode materials for the commercial application of ICRFBs.

在本文中，通过硅酸在热空气中蚀刻石墨毡获得了装饰有SiO _2的石墨毡，并研究了其作为铁铬氧化还原液流电池（ICRFB）电极的性能。通过扫描电子显微镜，比表面积分析，X射线光电子能谱，X射线衍射和拉曼光谱来详细表征SiO ₂装饰的石墨毡的表面形态，微观结构和表面化学组成。通过电化学阻抗谱，循环伏安法和单电池充放电循环测试研究了SiO ₂装饰的石墨毡的电催化活性以及在ICRFB中的性能。结果表明SiO ₂通过硅酸分解而引入的碳纤维可以增加石墨毡的有效比表面积，并同时促进在热空气中装饰有SiO _2的石墨毡的氧化。SiO ₂修饰的石墨毡的表面上的氧官能团的数目和缺陷位点大量增加，这尤其对ICRFB的负反应活性具有相当大的影响。用石墨毡组装而成的ICRFB，用50 wt％的硅酸蚀刻后作为电极，在电流密度为120 mA / cm ^2时的电压效率和能量效率分别为86.27％和79.66％分别。容量的衰减率每个周期仅为0.46％。本文证明的一种经济有效且方便的方法可以协调对氧官能团，表面积和石墨毡的电导率的控制，这可以为改进用于ICRFBs商业化应用的电极材料提供一个实例。