Improving Performance of a Passive Direct Methanol Fuel Cell by Hydrophobic Treatment for Cathode Current Collector

This study employs hydrophobic modification of the current collector to optimize cathode water management and enhance the performance of passive DMFCs. The surface of the cathode current collector was hydrophobized by polytetrafluoroethylene (PTFE) coating and titanium dioxide/polydimethylsiloxane (PDMS) composite coating. The experimental results showed that the surface hydrophobic treatment significantly improved the cell performance at low methanol concentration and marginally improved the cell performance at high methanol concentration. Among them, the DMFC with bilayer TiO2/PDMS hydrophobic-treated cathode current collector with a contact angle of 153.2° showed the best performance, which achieved superhydrophobicity and led to a peak power density that was 27.25% higher compared to the DMFC with an untreated current collector. With the gradient-based hydrophobic treatment for the cathode current collector, the best performance was achieved when double-layer TiO2/PDMS was used on the MEA side and PTFE coating on the air side.