Redox flow battery (RFB) systems have been developed to meet both the high-capacity energy storage demands and the safety concerns associated with the commonly used lithium ion batteries (LIBs). After the successful commercialization of vanadium redox flow battery, it has been integrated into other redox systems, both organic and inorganic. The redox behaviour of organic molecules could be fine-tuned by functionalizing with suitable electron donating and withdrawing groups. Hence, organic redox materials became the prime focus for the electrochemical energy researchers and their sustainability in organic and aqueous solvents were systematically examined. This review focuses on the development made in the key aspects of solubility, redox potential, multi-electron redox centres, cross-over issue and stability, both in aqueous and organic mediums. Some of new interesting ideas such as single molecule redox targeting reactions, eutectic mixture, bipolar redox molecules and symmetric flow battery were also discussed. With the developments made, we present our viewpoint on which renewable energy storage technology is suitable for sustainable energy storage.

已经开发出氧化还原液流电池 (RFB) 系统来满足高容量储能需求和与常用锂离子电池 (LIB) 相关的安全问题。在钒氧化还原液流电池成功商业化后，它已被整合到其他有机和无机氧化还原系统中。有机分子的氧化还原行为可以通过用合适的给电子和吸电子基团进行功能​​化来微调。因此，有机氧化还原材料成为电化学能源研究人员的主要关注点，并系统地研究了它们在有机和水性溶剂中的可持续性。本综述侧重于在水性和有机介质中的溶解度、氧化还原电位、多电子氧化还原中心、交叉问题和稳定性等关键方面的发展。还讨论了一些有趣的新想法，例如单分子氧化还原靶向反应、低共熔混合物、双极氧化还原分子和对称液流电池。随着发展的进展，我们提出了我们对哪些可再生能源存储技术适合可持续能源存储的观点。