(521i) Facile Electrochemical Synthesis and Energy Application for Porous Electroactive Polymer Hybrids

Tian, W., Massachusetts Institute of Technology
Mao, X., Massachusetts Institute of Technology
Brown, P., Massachusetts Institute of Technology
Rutledge, G. C., Massachusetts Institute of Technology
Hatton, T. A., Massachusetts Institute of Technology

Driven by the staggering demands for sustainable and efficient energy storage solutions, extensive research efforts have focused on the furtherance of pseudocapacitors with high power density to bridge the gap between batteries and dielectric capacitors. Instead of relying only on ion adsorption at the electrode surface to store charge, pseudocapacitors store charge via fast and reversible surface/near-surface redox reactions, typical of electroactive materials such as metal oxides and conducting polymers. Conducting polymers with conjugated backbones, though conductive, may suffer insufficient exposure to the electrolyte due to the often formed non-porous structure. Redox polymers with non-conjugated backbones, such as polyvinylferrocene (PVF), have rarely been used for energy storage due to their low intrinsic conductivity. Here we report a facile synthesis strategy for the preparation of a highly porous electroactive hybrid in which we exploit the π-π stacking interactions between pyrrole and the ferrocene moieties of PVF. The highly porous polymer films constructed in this way result in reduced ion diffusion limitations during the charge and discharge process. In addition, polypyrrole (PPy) chains here serve as molecular wires and improve the electronic conductivity of the hybrid. The formed hybrid demonstrated excellent electrochemical properties, directly arising from the synergistic effects between PPy and PVF. A specific capacitance of 514.1 F g-1 was achieved for the PVF/PPy hybrid, which was significantly higher than those of PPy (27.3 F g-1) and PVF (79.0 F g-1) alone. This interesting combination of properties from PPy and PVF opens up new opportunities for exploiting the intermolecular interactions to create highly porous polymer hybrids that consist of a wide selection of polymers with π-conjugated backbones and redox polymers with metallocene moieties.