Nanoporous Membrane Electrodes with an Ordered Array of Hollow Giant Carbon Nanotubes

This study proposes a next-generation model membrane electrode for fundamental electrochemical research of amorphous-based porous carbon materials. This novel electrode is fabricated by the uniform carbon coating of anodic aluminum oxide formed on an Al substrate and free from a barrier layer. The conformally carbon-coated layer forms vertically aligned giant carbon nanotubes, and their walls comprise low-crystalline stacked graphene sheets. The diameter and the length of the nanopores can be tuned over a broad range of between 10 to 200 nm and 2 to 90 mu m, respectively. Moreover, unlike composite electrodes made from other ordered nanoporous carbons, this model electrode exhibits an absence of inter-particle spacing and hence no contact resistance between particles. Thus, this model electrode provides representative nanopores of low-crystalline carbon materials. An atomic-scale structural model of the low-crystalline carbon walls is built with the aid of an in-house temperature-programmed desorption system to enable theoretical simulations to be performed. Using this model electrode, the electrical conductivity of low-crystalline carbon walls and mass transportation in an electric double-layer system are elucidated. This representative model electrode is expected to help clarify the complex electrochemical processes in porous carbon electrodes.