Electrochemical formation and dissolution of an iodine–halide coordination solid complex in a nano-confined space

Electrochemical formation and dissolution of an iodine–halide coordination solid complex, [(I 2 ) n ·X − ] (X − = Br − and I − ), occurs in the nanopores of electrodes in aqueous energy storage systems. Relative to [(I 2 ) n ·I − ]/I − , [(I 2 ) n ·Br − ]/I − exhibits superior capacity retention.