Then we assessed the Fe(Bhmbpy)3 cycling in three-chamber cells at higher initial pH to find the upper bound of operation pH. The cell setup and cycling conditions are the same as the lower bound test of operation pH. We prepared Fe(Bhmbpy)3 by adding 0.3 M Bhmbpy into 0.1 M FeCl2 without adjusting initial pH. The capacity fade of this cell is shown in Fig. . The fast fading was caused by constant hydroxide crossover from ferricyanide side into Fe(Bhmbpy)3 side. Hydroxide introduced unrecoverable dimerization of Fe(Bhmbpy)3. Dimerized complex precipitation was found in the electrolyte after cycling. The dimerization reaction can be described as following: 1