High-Performance Mesostructured Organic Hybrid Pseudocapacitor Electrodes

The electrodes of a hybrid electrochemical capacitor which utilize the quinone (Q)-hydroquinone (QH(2)) couple, a prototypical organic redox system known to provide fast and reversible proton-coupled electron-transfer reactions, are deterministically mesostructured via a colloidal templating strategy to provide good ion and electron transport pathways, enabling a high rate performance. Specifically, a conducting polymer, polypyrrole (PPy), is functionalized with a pseudocapacitive material, a Q/QH(2)-containing catechol derivative, by noncovalent interactions. The mesostructure of this hybrid material is formed into an ordered 3D porous structure by a polystyrene colloidal crystal template-assisted electrosynthesis. The catechol derivative is sufficiently bound to the PPy through noncovalent interactions to provide a volumetric capacitance as high as approximate to 130 F cm(-3) and a capacitance retention of approximate to 75% over 10 000 charging/discharging cycles. When compared with a randomly structured electrode, the deterministically structured electrode exhibits an improved rate performance due to the mesostructure facilitated electron and ion transport.