Freestanding and mechanically stable 3D hierarchical porous carbon electrodes decorated with functional species can enable high volumetric electrochemical activity. To participate in electrochemical reactions, active species not only need to be directly in contact with the current collector but also need to be accessible to reactants. We have developed a method to electrograft poly(diaminonaphthalene), PDAN, covalently onto a 3D nanocarbon structure which is formed by direct growth of carbon nanotubes on carbon cloth. Due to its fused aromatic ring nature, this polymer offers a high char yield of 70 wt% (N2 at 800 °C under 10 °C/min) . Three-tiered and well -defined porous structure, composed of micropores formed by carbon cloth, nanopores formed after carbon nanofiber growth and mesopores after polymer pyrolysis are formed to engender facile mass diffusion. In 0.5 M H2SO4, PDAN offers 900 F/g at 2 mV/sec. If we take into account the entire weight of the electrode, we achieve 100 F/g at 2 mV/sec. An analogous PDAN-carbon nanofiber composite was pyrolyzed in the presence of iron chloride. The N doped carbon derived from PDAN shows impressive ORR electrocatalytic activity. In 0.1 M perchloric acid, the half wave potential was at least 0.71V vs. RHE under a mass loading of 0.504 mg/ cm2 and a current gain of 4.9 mA/cm2. In 0.1 M KOH, the half wave potential was 0.88 V vs. RHE and a current gain of -4.3 mA/cm2 under a mass loading of 0.505 mg/ cm2. This holistic approach along with the choice of a new functional material can enable high performance energy storage and low-temperature polymer fuel cell technologies.

Freestanding 3D hierarchical carbon electrode enabled by poly(iaminonaphthalene) for energy storage and oxygen reduction reaction

255th National Meeting (2018)

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