Design and fabrication of non-noble metal catalyst-based air-cathodes for metal-air battery

In this paper, cost-effective non-noble metal catalyst-based air-cathodes are designed, developed, and fabricated for a metal-air battery, particularly in a non-toxic neutral solution environment (sodium chloride). The air-cathode and its fabrication method comprise two gas diffusion layers (GDLs) bonded on to each side of the current collector (nickel mesh) by a rolling method, and a catalyst layer bonded on one GDL by a spraying method. The GDL paste consists of carbon powder and hydrophobic chemicals, and the catalyst layer contains non-noble metal catalyst, carbon powder, and hydrophilic chemicals. Several characterization techniques such as DTA/TG thermal analysis, electrochemical impedance spectroscopy, linear sweep voltammetry, and their associated theories are used to understand the properties and performance of the developed air-cathodes. The advantages of the current method of forming the air-cathode can decrease the internal electronic resistance and gas flow restriction of the system, and therefore increase air permeability as well as water transportation to the reaction sites. By using such an integrated structure of an air diffusion cathode, the cost-effectiveness in terms of materials and manufacturing compared to the commercial air-cathode, and the overall fabrication procedure is achieved, and the method can be easily transferred into a continuous industrial manufacturing process.