Improved Performance of High-Temperature Proton Exchange Membrane Fuel Cells by Purified CNT Nanoporous Sheets

Abstract

Given environmental friendliness, high-temperature proton exchange membrane fuel cells (HT-PEMFCs) can be the alternative power source for clean power generation. However, neither developments nor strategies of diffusion media are actively conducted yet to achieve high-performance HT-PEMFCs. Herein, a nanoporous carbon nanotube (CNT) sheet, a new anode diffusion layer between the gas diffusion layer|bipolar plate interface that improves fuel cell performance and durability by CNT purification for facilitating fuel accessibility with uniform interfacial contact for reducing acid loss, is reported. Configuration of the optimal CNT-inserted fuel cell is examined and proposed under the operating temperature of 140-200 degrees C. The underlying mechanism of this new diffusion layer with multiphysics simulation elucidates that the nanoporous nature induces gas-wall collision, enabling uniform dispersion within adjacent diffusion media. These fuel cells outperform performance over two times higher and have a voltage decay rate nearly two times lower than conventional HT-PEMFC. A purified nanoporous carbon nanotube (CNT) sheet with few impurities is synthesized and inserted between the anode gas diffusion media and bipolar plate. The CNT-inserted fuel cell notably improves performance and durability. Fuel cell testing combined with multiphysics simulation reveals that optimal nanoporous media increases gas-wall collision, thereby achieving uniform gas dispersion in the fuel cell.image