Yang Jiahui, Wei Wei, Zhou Chengxi, Yan Hui, Che Hangxin, Hao Leiduan, Tan Xinyi, Robertson Alex W, Wu Tai-Sing, Soo Yun-Liang, Tang Ao, Sun Zhenyu
State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, 100029, Beijing, P. R. China.
Institute of Metal Research Chinese Academy of Sciences, 110016, Shenyang, P. R. China.
Angew Chem Int Ed Engl. 2025 Jan 10;64(2):e202414452. doi: 10.1002/anie.202414452. Epub 2024 Nov 2.
All-soluble all-iron redox flow batteries (AIRFBs) are an innovative energy storage technology that offer significant financial benefits. Stable and affordable redox-active materials are essential for the commercialization of AIRFBs, yet the battery stability must be significantly improved to achieve practical value. Herein, ferrous complexes combined with the triisopropanolamine (TIPA) ligand are identified as promising anolytes to extend battery life by reducing cross-contamination due to a pronounced steric hindrance effect. The coordination structure and failure mechanism of our Fe-TIPA complexes were determined by molecular dynamics simulation and spectroscopic experiments. By coupling with [Fe(CN)], Fe-TIPA/Fe-CN AIRFBs retained excellent stability exceeding 1831 cycles at 80 mA ⋅ cm, yielding an energy efficiency of ~80 % and maintaining a steady discharge capacity. Moreover, the all-soluble electrolyte was tested in an industrial-scale Fe-TIPA/Fe-CN AIRFB prototype energy storage system, where an energy efficiency of 81.3 % was attained. Given the abundance of iron resources, we model the TIPA AIRFB electrolyte cost to be as low as 32.37 $/kWh, which is significantly cheaper than the current commercial level. This work demonstrates that steric hindrance is an effective measure to extended battery life, facilitating the commercial development of affordable flow batteries.
全溶性全铁氧化还原液流电池（AIRFBs）是一种创新的储能技术，具有显著的经济效益。稳定且价格合理的氧化还原活性材料对于AIRFBs的商业化至关重要，但电池稳定性必须大幅提高才能实现实际应用价值。在此，与三异丙醇胺（TIPA）配体结合的亚铁配合物被确定为有前景的阳极电解液，可通过显著的空间位阻效应减少交叉污染来延长电池寿命。通过分子动力学模拟和光谱实验确定了我们的Fe-TIPA配合物的配位结构和失效机制。通过与[Fe(CN)]耦合，Fe-TIPA/Fe-CN AIRFBs在80 mA·cm下保持了超过1831次循环的优异稳定性，能量效率约为80%，并保持稳定的放电容量。此外，在工业规模的Fe-TIPA/Fe-CN AIRFB原型储能系统中对全溶性电解液进行了测试，实现了81.3%的能量效率。鉴于铁资源丰富，我们将TIPA AIRFB电解液成本模拟为低至32.37美元/千瓦时，这比当前商业水平便宜得多。这项工作表明，空间位阻是延长电池寿命的有效措施，有助于经济实惠的液流电池的商业发展。
