Redox slurry electrodes: advancing zinc-based flow batteries for sustainable energy storage

As global demand for renewable energy continues to grow, developing efficient, sustainable, and long-term energy storage systems becomes increasingly critical. Zinc-based liquid flow batteries have attracted much attention due to their high energy density, low cost, and environmental-friendliness. This review discusses the latest progress in sustainable long-term energy storage, especially the development of redox slurry electrodes and their significant effects on the performance of zinc-based liquid flow batteries. The redox slurry electrode can enhance charge transfer efficiency and promote chemical bonding between redox species and the carbon skeleton by combining low-density carbon materials with specific porosity and an optimized sp2/sp3 carbon ratio. These advances not only address the energy loss issue caused by the shuttling of redox species in traditional zinc-based flow batteries but also enhance the adsorption capacity of the electrode, improve battery charge and discharge stability, and extend cycle life effectively. Additionally, the application of low-cost choline salt water electrolytes in zinc-based liquid flow batteries is explored. This new electrolyte not only reduces the cost of the battery but also improves the safety and environmental compatibility of the system. By analyzing current research challenges and predicting future development directions, this paper aims to provide a comprehensive perspective for researchers and engineers to promote further innovation and application of zinc-based flow battery technology, particularly in sustainable energy storage. The development of redox slurry electrodes presents a new opportunity for enhancing the performance and expanding the applications of zinc-based liquid flow batteries, marking a significant milestone in sustainable, long-term energy storage solutions. With further research and technological advancements, zinc-based flow batteries are expected to play a key role in the global energy transition.