Cilia‐Inspired Functional Channels for High‐Speed and Directional PEMFC Drainage

Abstract Proton Exchange Membrane Fuel Cells (PEMFC) consist of channels that require efficient drainage for optimum performance. However, it remains a grand challenge to achieve both directed and high‐speed active drainage in PEMFC channels. This greatly limits current PEMFC performance. Herein, inspired by respiratory cilia, a bioinspired structural design strategy is introduced into the channel surface to significantly enhance its active droplet transport efficiency. Two artificial cilia arrays are fabricated and named as plane‐bottom artificial cilia array (PACA) and concave‐bottom artificial cilia array (CACA) according to their respective shapes. PACA demonstrates stable directional transport. The droplet speed reaches as high as 86 mm s −1 with droplet volumes ranging from 10 to 20 µL. This is surpassed by CACA. Its speed reaches as high as 163 mm s −1 for droplet volumes ranging from 10 to 50 µL. PEMFC experimental evaluation of diameter sizes shows that CACA can be tuned for enhancing its electrochemical performance. CACA‐8 achieves the maximum power density (0.5339 W cm −2 ) at 1.1864 A cm −2 , representing an 18.70% increase compared to conventional PEMFC channels. This work provides a promising strategy for the stable and efficient transport of liquid water in PEMFC.