Super Proton Conductive Nafion/Short Fiber/Nanosilica/Deep Eutectic Solvent (DES) Composite Membrane for Application in Anhydrous Fuel Cells

The aim of present study is to reduce the tortuosity of proton conductive pathways within the polymer electrolyte membranes (PEMs) for application in anhydrous PEM fuel cells. For this purpose, for the first time, microsize chopped fibers (modified glass wool fibers), modified nanosilica, and a deep eutectic solvent (DES) are incorporated into the Nafion matrix to extend proton conductive pathways. The long length of the fibers as new and cheap additives creates a continuous interface within the polymer matrix which significantly improves its proton conductivity, likely by reducing the tortuosity of proton conductive pathways. While nanosilica promotes the connectivity of the short fibers, EG/NaBr-based DES is also used as a nonaqueous electrolyte to maintain proton conductivity at anhydrous conditions. The measurements show super proton conductivity beyond 1400 mS cm(-1) at 100 degrees C and anhydrous conditions for the Nafion/DES composite membrane containing 5 wt% short fibers and 2 wt% nanosilica. Furthermore, fuel cell performance of the prepared membranes shows a promising result by providing a maximum power density of 715 mW cm(-2) at 95 degrees C. This study clearly shows the important role of ionic paths within the PEMs to achieve desirable properties in the real condition of a fuel cell system.

Automated summary

The aim of this study is to reduce the tortuosity of proton conductive pathways within polymer electrolyte membranes for anhydrous PEM fuel cells. By incorporating microsize chopped fibers, modified nanosilica, and a deep eutectic solvent into the Nafion matrix, the proton conductive pathways are extended and the conductivity is greatly improved. The measurements show that the Nafion/DES composite membrane with 5 wt% short fibers and 2 wt% nanosilica exhibits super proton conductivity and promising fuel cell performance.