The cyclic stability of a cell with OMIM-Cl has been evaluated by chronopotentiometry upon charging for one hour and the following discharge at 25 • C. Figure shows the values of the specific power density (Wh/kg) and specific charge (mAh/g) for 100 cycles. The corresponding values of the coulombic efficiency (%) are plotted in Fig. . The current was set at 50 µA during the first four cycles in order to account the initial potential reduction, and then raised to ±60 µA for the rest of the cycles. First of all, both capacity and power density are constantly larger with the positive current charging (upper panel), owing to the chlorination of the MOF. With the negative current (lower panel), the device can still be charged up to a smaller extent, that can be attributed to the intercalation of the MOF@CNT cathode with OMIM + and/or the intercalation of the CNT anode with Cl -. This capacity is largely reduced over 60 cycles to reach an equilibrium (see the lower panel) at which the intercalations no longer occur. With the positive current (upper panel), the similar reduction in capacity is observed as OMIM + can intercalate the CNT anode, while the charge associated with the chlorination of the MOF seems to keep the initial level after 100 cycles. Note that a bistability becomes apparent after 10 cycles, whose origin remains to be unknown. Despite the bistability, the data demonstrate excellent cyclic stability of the redox reactions.