Bubble-trap layer for effective removing gas bubbles and stabilizing power generation in direct liquid fuel cell

Abstract

The power generation property of direct liquid fuel cells at high current densities is plagued by gas bubbles generation. Herein, we propose a bubble-trap layer to help mitigate the problem and improve the power generation stability performance. A novel chip-based liquid fuel cell with the bubble-trap layer is fabricated as a facile visualization and fast test platform, validating that most of CO2 bubble releases from the bubble-trap layer in situ rather than at the microchannel outlet. The dynamic behaviors of gas bubbles are visualized and their impact on the power generation performance is discussed. It suggests the fuel cell equipped with the bubble-trap layer has superior power generation stability, power density (29 mW cm−2) and current density (163 mA cm−2), which are 10% and 27% higher than that without the bubble-trap layer. And a maximum power density of 35 mW cm−2 is achieved. The bubble growth and gas emission mechanisms are analyzed according to the mechanical model, providing a guidance for the channel design and operation condition determination of cells. These results demonstrate the viability of applying the bubble-trap layer for stabilizing power generation and cast new light on the structure design of direct liquid fuel cells.