The development of a magnesium-hydrogen peroxide semi-fuel cell

The Naval Undersea Warfare Center (NUWC) Division Newport, Rhode Island is presently developing a magnesium-solution phase catholyte semi-fuel cell (Mg-SFC) as an energetic electrochemical system for low rate, long endurance unmanned undersea vehicle (UUV) applications. This novel electrochemical couple consists of a magnesium anode and a solution phase catholyte of hydrogen peroxide together with a seawater electrolyte. Critical to this effort was the successful development of a unique catalytic compound consisting of palladium and iridium together with a carbon based substrate, greatly enhancing the electrochemical reduction of hydrogen peroxide. An overall cell potential increase of +0.9 V (1.25 V to 2.12 V) was observed with this catalyst in place of the prior silver based catalyst; representing a 69.6% increase in cell voltage. To further enhance the reduction potential at the positive electrode and the subsequent increased specific energy of this system, NUWC has collaborated with The University of Massachusetts to develop and synthesize a novel high surface area per unit volume microfiber carbon electrode (MCE) using a textile science flocking technique. Use of the flocking technique, which involves the alignment and placement of highly conductive and high surface charge carbon microfibers via a high potential electric field (40 kV to 70 kV), has not been reported upon in the scientific literature. Volumetric surface area of 182 cm²/cm³ has been achieved, and the resulting electrochemical payoffs are discussed.