Study on Self-Humidification in PEMFC with Crossed Flow Channels and an Ultra-Thin Membrane

Abstract

In this study, a 3D model of a proton exchange membrane fuel cell (PEMFC) with crossed channels and an ultra-thin membrane is developed to investigate the feasibility of self-humidification; experiments utilizing a PEMFC stack with identical configurations are conducted to validate the simulation results and further investigate the effects of various operating conditions (OCs) on self-humidification. The results indicate that the crossed flow channel leads to enhanced uniformity of water distribution, resulting in improved cell performance under low/no humidification conditions. External humidifiers for the anode can be removed since the performance difference is negligible (≤3%) between RHa = 0% and 100%. Self-humidification can be achieved in the stack at 90 °C or below with an appropriate back pressure among 100–200 kPa. As the current density increases, there is a gradual convergence and crossing of the voltage at low RH with that at high RH, and the crossover points are observed at 60–80 °C with suitable pressure when successful self-humidification is achieved. Below the current density of the point, the stack’s performance is inferior at lower RH due to membrane unsaturation, and conversely, the performance is inferior at higher RH due to flooding; this current density decreases with higher pressure and lower temperature.

Enhancing Performance and Stability of High-Temperature Proton Exchange Membranes through Multiwalled Carbon Nanotube Incorporation into Self-Cross-Linked Fluorenone-Containing Polybenzimidazole

“…High-temperature proton exchange membrane (HT-PEM) fuel cells (HT-PEMFCs), operating above 120 °C, have garnered extensive research attention due to their superior carbon monoxide (CO) tolerance and simplified hydrothermal management. − The PEM plays a pivotal role in HT-PEMFCs, employing various polymers for this purpose. ,− Notably, sulfonated polyetheretherketone, − polybenzimidazole (PBI), − sulfonated polysulfone, and poly­(vinyl alcohol) (PVA) are among the majorly studied PEMs. Phosphoric acid (PA)-doped PBI membranes stand out as a particularly promising system for HT-PEMFCs, owing to their remarkable thermal stability, PA stability, aging resistance, and modifiable polymer backbone. − The proton conductivity of PA-doped PBI membranes directly correlates with their PA content, influencing proton transport through PA hydrogen-bond networks.…”