New-generation iron–titanium flow battery (ITFB) with low cost and high stability is proposed for stationary energy storage, where sulfonic acid is chosen as the supporting electrolyte for the first time. In the design, the complexation between the sulfate ion and TiO²⁺ inhibits the hydrolysis of TiO²⁺ ions and improves the stability of the electrolyte. Combining the experimental characterization and the theory calculation, the stabilization mechanism of the electrolyte and the existing forms of TiO²⁺ ions in the electrolyte are explored deeply. Moreover, by electrodepositing metal Bi on the surface of the electrode, the electrochemical activity of the Ti³⁺/TiO²⁺ couple is effectively improved. As a result, the new-generation ITFB demonstrates coulombic efficiency of 99.7% and energy efficiency of 85.6% at the current density of 40 mA/cm² and can run stably for more than 1000 cycles without obvious efficiency decay. Most importantly, after 1000 cycles, the discharge capacity still keeps 80% of the initial capacity, stating the extremely slow capacity decay (0.193 mAh/cycle). Furthermore, a low-cost and easily prepared sulfonated poly(ether ether ketone) (SPEEK) membrane, instead of the expensive Nafion membranes, is successfully used in the ITFB, feathering a very competitive cost advantage (less than 88.22 $/kWh). Therefore, considering the ultrahigh stability and low cost, it is easy for the new-generation ITFB to scale up and industrialize, thus new-generation ITFB is expected as a large-scale energy storage device in the foreseeable future.

提出了用于固定式储能的低成本、高稳定性的新一代铁钛液流电池（ITFB），其中首次选择磺酸作为支持电解质。在设计中，硫酸根离子与TiO ²⁺的络合抑制了TiO ²⁺离子的水解，提高了电解液的稳定性。结合实验表征和理论计算，深入探讨了电解液的稳定机理以及电解液中TiO ^{2+离子的存在形式。}此外，通过在电极表面电沉积金属Bi，提高了Ti ³⁺ /TiO ^{2+的电化学活性。}夫妇得到有效改善。结果，新一代ITFB在40 mA/cm ^{2的电流密度下表现出99.7%的库仑效率和85.6%的能量效率}并能稳定运行1000次以上，无明显效率衰减。最重要的是，经过 1000 次循环后，放电容量仍保持在初始容量的 80%，说明容量衰减极慢（0.193 mAh/循环）。此外，一种低成本且易于制备的磺化聚醚醚酮 (SPEEK) 膜代替昂贵的 Nafion 膜已成功用于 ITFB，具有极具竞争力的成本优势（低于 88.22 美元/kWh）。因此，考虑到超高稳定性和低成本，新一代ITFB易于规模化和产业化，在可预见的未来，新一代ITFB有望成为大规模储能器件。