In this paper, thiourea was successfully grafted onto the surface of acid preprocessed graphite felts [sulfuric acid-treated graphite felt (SA-GFs)] by thiol-carboxylic acid esterification. The thiourea-grafted graphite felts (TG-GFs) were investigated as the positive electrode for vanadium redox flow battery (VRFB). X-ray photoelectron spectroscopy results suggested that thiourea was grafted into the surface of graphite felts. The cyclic voltammetry showed that the peak potential separation decreased by 0.2 V, and peak currents were greatly enhanced on TG-GF electrode compared with SA-GF electrode, implying improved electro-catalytic activity and reversibility of TG-GF electrode toward VO²⁺/VO2+ redox reaction. The initial capacity of TG-GF-based cell reached 55.6 mA h at 100 mA cm⁻², 22.6 mA h larger than that of SA-GF-based cell. The voltage and energy efficiency for TG-GF-based cell increased by 4.9% and 4.4% compared with those of SA-GF-based cell at 100 mA cm⁻², respectively.

本文通过硫醇-羧酸酯化成功地将硫脲接枝到酸预处理的石墨毡[硫酸处理过的石墨毡（SA-GFs）]的表面上。研究了硫脲接枝石墨毡（TG-GFs）作为钒氧化还原液流电池（VRFB）的正极。X射线光电子能谱分析结果表明，硫脲被接枝到石墨毡的表面。循环伏安法表明，与SA-GF电极相比，TG-GF电极的峰电位分离降低了0.2 V，并且峰电流大大增强，这意味着TG-GF电极对VO ²⁺ /的电催化活性和可逆性得到改善。VO2+氧化还原反应。TG-GF基电池的初始容量在100 mA cm ^-2时达到55.6 mA h，比SA-GF基电池的初始容量大22.6 mA h。与基于SA-GF的电池相比，基于TG-GF的电池在100 mA cm ^-2时的电压和能量效率分别提高了4.9％和4.4％。