Simple-Synthesized Sulfonated Ferrocene Ammonium for Aqueous Redox Flow Batteries
Yiwen Yao, He Xu, Zhongzhen Tian, Jing Zhang, Fuxu Zhan, Mei Yan, Chuankun Jia
Abstract
To achieve sustainable development, the development and utilization of redox-active organic species in aqueous redox flow batteries provide broad prospects for large-scale and sustainable energy storage. Herein, we report a sulfonated ferrocene derivative, ferrocene ammonium sulfonate, that is stable and easy to synthesize. We applied it as a catholyte in zinc hybrid flow batteries. Through the adjustment of the electrolyte, the battery showed high capacity retention and efficiency. When the current density was 20 mA/cm2 and 0.5 M NaCl + 0.5 M NH4Cl solution was used as the supporting electrolyte, the capacity retention reached 92.55% after 100 consecutive charge/discharge cycles. In addition, the coulombic efficiency, energy efficiency, and voltage efficiency stayed at 98.33, 83.19, and 84.60%, respectively. This battery design puts forward an idea for developing low-cost materials and improving capacity retention.