A self-breathing metallic micro-direct methanol fuel cell with the improved cathode current collector

A self-breathing micro-direct methanol fuel cell (μDMFC) with active area of 0.64 cm2 has been developed for powering portable applications. A cathode perforated current collector with parallel flow fields is presented in order to improve the cell performance. Compared with the conventional cathode self-breathing structure, the improved one can enhance oxygen transport and reduce water flooding utilizing multiphysics simulations. The stainless steel plates with the thickness of 0.3 mm as current collectors with parallel flow fields have been machined by thermally micro-stamping. For the cathode self-breathing openings, the perforated current collector has been realized using laser drilling. A 500 nm-thick titanium nitride (TiN) layer is deposited onto the surface of current collectors by magnetron sputtering ion plating (MSIP) technology to cover the cracks and prevent corrosion. Peak power density of the μDMFC reaches 27.1 mW/cm2 at room temperature with 1.0 M methanol solutions of 1 ml/min. The results presented in this paper might be helpful for the development of micro power sources applied in future portable electronic devices.