This study investigates the impact of vibration frequency on the performance of a 10-cell open-cathode direct methanol fuel cell (OC-DMFC) stack. Experiments were conducted using three different vibration frequencies (15, 30, and 60 Hz) and compared against a baseline condition without vibration. Performance was evaluated under varying methanol–water fuel flow rates (1, 5, 25, and 50 mL·min⁻¹) while maintaining constant operating conditions: methanol temperature at 70 °C, methanol concentration at 1 M, and cathode air flow velocity at 4.8 m·s⁻¹. The optimal performance was observed at a fuel flow rate of 5 mL·min⁻¹, where the maximum power density reached 26.05 mW·cm⁻² under 15 Hz vibration—representing a 14% increase compared to the non-vibrated condition. These findings demonstrate that low-frequency vibration can enhance fuel cell performance by improving mass transport characteristics.

The flow field design in the bipolar plate, which is a DMFC structure, is extremely important in the mass transfer in the fuel cell and the electrochemical reactions occurring in the cell. One of the main purposes of DMFC is to improve the flow plate in order to provide less pressure drop in all channels. Therefore, different leaf types have been investigated to improve the flow distribution performance of DMFC. Populus, Large-surface Bamboo, Palm, Philodendron, Lotus, Mulberry, Loquat and Fig leaves with similar properties were sized using the COMSOL Multiphysics program and designed by examining their environmental and physical properties. Flow and pressure distributions in accordance with the flow field design similar to leaf dimensions in two dimensions were investigated. The biological and physical properties of each bio-inspired leaf design are described and its compliance with the DMFC is explained. Finally, flow images are presented with a comparison of flow areas. When these studies in the literature are examined; while applying the bio-inspired approach, it was seen that the shape similarity approach was adopted. However, by specifying the leaf, the flow field was not created exactly in the size of the leaf. Although there is a research on the flow design in the PEM fuel cell, it has not been used at the same rate for the DMFC. Considering that it is suitable for the DMFC system with the flow channel designs in the bipolar plate in question, it is expected that the performances that will increase the flow transmission to optimum levels will also increase when used.