Additionally, in the aged solutions, orange-brown precipitates were observed, similar to those seen in the full-cell experiments (Figure ). This is in contrast to the 2,6-DHAQ simulated-crossover experiments performed in ferrocyanide, where no colour changes or precipitate was observed on aging (Figure ). Overall, the results from these simulated-crossover experiments mimic the effects seen in the full-cell studies, where losses in 2,6-DHAQ and ferricyanide are seen concurrently at high state-of-charge (Figure , grey shaded box). As these losses in ferricyanide and 2,6-DHAQ are also detected in the simulated-crossover experiments, in the absence of an applied voltage, this indicates that the two components are reacting chemically.