Proton exchange membrane fuel cell (PEMFC) is a power generation device that converts chemical energy stored in hydrogen and oxidants directly into electricity through electrochemical reaction, which is of great significance to future energy strategy. The flow field structure of the bipolar plates, which is the main component of PEMFC, is one of the important factors affecting the water management and performance of fuel cell. Through multi-scale optimization design of flow field structure, directional continuous transportation of produced water in the channel will realize. Such an approach can improve the performance and reduce the cost of the fuel cell.

The carnivorous pitcher plant, Nepenthes, can capture insects to meet their fundamental nutrient needs through their peristome. The peristome can be completely wetted by water and then form a slippery liquid film, which induces insects to “aquaplane” on it. This gives inspiration for designing well-known slippery directional continuous transportation surfaces.

There is a special micron multi-scale wedge-shaped blind hole array structure on peristome surface. This structure spontaneously forms gradient Taylor capillary rise, which makes the peristome surface have the ability of water unidirectional rapid and continuous transportation. Under the action of this force, the water can continuously fill in the wedge-shaped blind hole and evenly spread to form a liquid film. Moreover, this structure will firmly hold water in its original position so that the peristome surface will remain super-wet and slippery constantly. The insect cannot escape and easily slide into the cage to be preyed on.

Based on the inspiration gained from the peristome structure of Nepenthes, researchers have fabricated a variety of surfaces equipped with unidirectional liquid transport function. The application of such designs on the bipolar plates of fuel cell will lead to higher efficiency of gas utilization and water removal, which can significantly improve the performance of fuel cell.

[1] CHEN H, ZHANG L, ZHANG P, et al. A Novel Bioinspired Continuous Unidirectional Liquid Spreading Surface Structure from the Peristome Surface of Nepenthes alata [J]. Small, 2017, 13(4): 1601676.

[2] LI J, ZHENG H, YANG Z, et al. Breakdown in the directional transport of droplets on the peristome of pitcher plants [J]. Communications Physics, 2018, 1(1): 35.

[3] CHEN H, RAN T, GAN Y, et al. Ultrafast water harvesting and transport in hierarchical microchannels [J]. Nature Materials, 2018, 17(10): 935-42.

[4] ZHANG P, ZHANG L, CHEN H, et al. Surfaces Inspired by the Nepenthes Peristome for Unidirectional Liquid Transport [J]. Advanced Materials, 2017, 29(45): 1702995.

[5] Yi Baolian. Development and Technology Status of Fuel Cell and Fuel Cell Vehicle [M]. Beijing: The Science Publishing Company, 2018.

Jiang Lei

Chen Hua-wei

Zhang De-yuan

Wang Zuan-kai

Technical institute of physics and chemistry, CAS；

Beihang University；

City University of Hong Kong；

Dalian Institute of Chemical Physics, CAS