Hierarchical 3D Carbon Based Electrodes for Energy Storage and Conversion
Renewable energy is regarded as the most effective tool to combat climate change/global warming. Electrochemical reactions are the cornerstone for these technologies. I present a fabrication process to create hierarchical structures with engineered functional groups (redox species for repeated electrochemical reactions or catalyst species for electrochemical reactions) uniformly distributed on an electrode aiming for enhanced device performance. For energy storage applications, poly (1,5-diaminonaphthalene) (PDAN) and polyaniline (PANI) have been oxidatively electrografted onto carbon for side by-side comparison. It has been found that PDAN offers 17% higher theoretical capacitance than PANI. More impressively due to the rigid highly conjugated nature PDAN has a more stable cycle stability than PANI. This lightweight platform with high energy density and enhanced cycle stability opens the door to a wide array of electrochemical storage applications. For energy conversion applications, metal-nitrogen coordinated species are a low-cost alternative to platinum. In this study poly (4-vinylpyridine) (P4VP) has been cathodically electrografted onto carbon substrates. The effect of ligands and metal species on coordination and catalytic activity was investigated by keeping all other parameters(interface properties, spatial distribution, and relation with electrodes) the same. Cobalt-containing catalysts have demonstrated the best catalytic activity compared to tin and iron-based catalysts. This platform is expected to provide a tool to screen a variety of catalyst systems.