Metal-Containing Ceramic Composite with in-Situ Grown Carbon Nanotube as a Cathode Catalyst for Anion Exchange Membrane Fuel Cell and Rechargeable Zinc-Air Battery

Abstract

The development of new air-breathing cathode catalyst not only addresses the performance of fuel cells and metal-air batteries but also make them cheaper. Herein, we developed a new, metal containing (Ni, Co, Pt and their alloys) ceramic composite as a cathode electrocatalyst for anion exchange membrane fuel cell (AEMFC) and zinc-air battery (ZAB) application. The porous ceramic foams were generated with the help of a sacrificial template method in which polystyrene beads were infiltrated with a polysiloxane precursor. With addition of metal salts into the porous ceramic matrix, the formation of carbon nanotubes (CNTs) by applying catalyst-assisted pyrolysis was facilitated. The in situ grown CNTs in composite ceramic affect the charge transport and drastically improved the electrical conductivity of up to 6 orders in magnitude compared with the bare ceramics (H.A). The best performing Ni-containing ceramics (H.A.Ni) show improved oxygen reduction activity in half-cell measurements and for AEMFC delivered an open-circuit voltage of 0.65 V with a maximum power density of ∼10 mW cm-2. In rechargeable ZAB systems, the H.A.Ni showed excellent battery performance with a specific capacitance of 490 mAh g-1, maximum power density of 110 mW cm-2, and excellent discharge/charge cycle stability over 300 cycles. Results indicate that the presence of CNT and intermetallic silicides such as Ni2Si and Ni31Si12 tunes the electrical properties and enhances the electrocatalytic activity toward oxygen. Thus, the Ni-containing ceramic material is as an excellent cathode catalyst for AEMFC and rechargeable ZAB applications.