Charles J. Patrissi

Fabrication and Rate Performance of a Microfiber Cathode in a Mg-H2O2 Flowing Electrolyte Semi-Fuel Cell

Three-dimensional electrodes based on an array of carbon microfibers were prepared by a process called direct-charging electrostatic flocking. The cathodes comprised carbon fibers 11 μm in diameter and 500 μm long that protruded from a titanium foil support like blades of grass. The fiber density was 125,000 fibers per cm 2 of geometric area. The fibers were coated with an alloy of Pd and Ir to catalyze hydrogen peroxide reduction. The electrochemical performance of catalyst-coated carbon microfiber arrays (CMAs) was investigated in a flowing electrolyte Mg-H 2 O 2 semi-fuel cell. In these studies, CMA-based cathodes showed higher voltages at high current densities, better power densities, and equivalent H 2 O 2 utilization compared to planar cathodes with the same loading of catalyst.

Recent Developments in Borohydride Fuel Cells

Developments in direct borohydride fuel cells (DBFC) are considered together with electrolyte stability and the choice of membrane and electrode materials. The cyclic voltammetry of borohydride oxidation was studied at three electrodes: a) gold on carbon, Au/C, b) gold on titanate nanotubes, Au/TiN and (c) gold foil. Similar currents were observed from the three electrodes. A DBFC in a single, 2- and 4-bipolar cell configuration with Au/C anode and Pt/C cathode produced 2.2, 3.2 and 9.6 W showed cell voltages of 1.06, 0.81 and 3 V, respectively. In another single cell, the reduction of peroxide on a Pd/Ir coated microfibrous carbon cathode was catalytically more active than a platinised-carbon one. The maximum power density achieved was 78 mW cm-2 at a cell voltage of 1.09 V. The need for further research is highlighted, particularly into new electrocatalyst materials