Performance enhancement of proton exchange membrane fuel cells with bio-inspired gear-shaped flow channels.

• A planthopper gear-shaped flow channel for PEMFCs is developed. • The oxygen transport mechanism inside the GFCH-based PEMFC is revealed. • The effects of GFCHs for mitigating the oxygen starvation and boosting the reactant homogeneity in PEMFC are analyzed. • A PEMFC with an optimal GFCH with remarkable electrochemical performance is provided. The flow channel design of a proton exchange membrane fuel cell (PEMFC) is a key factor affecting the power output. This work proposes a planthopper gear-shaped flow channel (GFCH) to address the issues of oxygen starvation and reactant homogeneity in a PEMFC by strengthening oxygen transport from the flow channel to the electrode surface. Full-scale three-dimensional PEMFC based on the GFCHs is constructed to investigate and analyze the multi-phase mass transport process, flow velocity, pressure distribution and electrochemical performances, compared with the conventional serpentine flow channels (SFCHs). Results show that the GFCH remarkably boosts the oxygen transport to the electrode surface under the effects of bio-inspired strengthened structures. Due to the promoted mass transfer efficiency and reactant distribution homogeneity of the GFCHs, the peak power density of the optimized flow channel (1.04 W cm−2) is ∼ 46% higher than that of the conventional SFCH (0.71 W cm−2). The optimal structural parameters for the GFCH with 0.4 mm for the rib width and a combination of 0.6/0.4 mm for the channel height are obtained by simulation and experimental demonstration. We believe that using this novel channel shape provides a good solution for flow channel design of PEMFCs. [ABSTRACT FROM AUTHOR]