The 2,6-dihydroxyanthraquinone (2,6-DHAQ)/ferrocyanide battery was the first example of a anthraquinone/ferrocyanide battery (Scheme 1), and it has since been used as a model AORFB in numerous studies. In the pioneering work by Zhao et al., on-line NMR was used to provide the first direct evidence for the previously proposed two-step, single-electron electrochemistry of 2,6-DHAQ in this battery. Additionally, this work revealed that a 1.7 V cell voltage hold results in the electrochemical degradation of 2,6-DHAQ into anthrone and anthrol derivatives. Building on these studies, Jing et al. demonstrated that 2,6-DHAQ could be regenerated from these electrochemical degradation products using a deep discharge to -0.2 V. By implementing this regeneration step, capacity fade rates (i.e., the rate of decline in maximum energy storage capacity) can be vastly reduced from 6.45% per day to 0.38% per day. Importantly, these pivotal studies were supported by on-line NMR analysis, highlighting the importance of this technique to the advancement of redox flow batteries. Scheme 1: Redox reactions utilised in the alkaline 2,6-DHAQ/ferrocyanide redox flow battery.