Two-Dimensional Polydopamine Positive Electrodes For High-Capacity Alkali Metal-Ion Storage

Redox-active organic compounds have attracted substantial attention as charge storage materials, owing to their high theoretical capacity. Herein, a two-dimensional organic electrode material is prepared by using hydrothermally polymerized dopamine molecules on graphene nanosheets. Two-dimensional polydopamine is employed as a positive electrode for storing alkali metal ions based on the surface redox reaction between oxygen functional groups and alkali ions. The two-dimensional polydopamine positive electrodes deliver high capacities of 255 mAh g(-1) in Li cells, 150 mAh g(-1) in Na cells, and 124 mAh g(-1) in K cells at 0.1 A g(-1), demonstrating a promising organic positive electrode for rechargeable alkali-ion batteries.