Performance And Durability Enhanced Composite Nanomaterial Membrane For Fuel Cell Applications

Abstract

The proton exchange membrane (PEM) based on polybenzimidazole (PBI) is developing into a promising alternative to Nafion for high-temperature proton exchange membrane fuel cells (HT-PEMFC). While Nafion membranes are effective at atmospheric pressure and low temperatures, their performance deteriorates significantly at temperatures above 80 °C, making them unsuitable for the operation of HT-PEMFCs. PBI membranes, on the other hand, have excellent thermal stability and durability, making them well-suited for high-temperature conditions. However, their relatively low proton conductivity (between 10-15 mS/cm) poses a challenge for efficient HT-PEMFC performance. This study aims to synthesise and investigate the effects of incorporating the ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]) on the physicochemical properties, ionic characteristics, and overall performance of polybenzimidazole/graphene oxide (PBI-GO) composite membranes in HT PEMFCs. The PBI composite membranes were prepared with a fixed weight percentage of 2 wt% graphene oxide (GO) and different concentrations of [BMIM][Cl] (from 1 to 3 wt%) by the solution casting method. The results showed that the composite membrane with 2 wt% [BMIM][Cl] (PBI-GO-[BMIM][Cl] (2 wt%)) exhibited optimal ion morphology distribution and lower acid leaching (about 54% loss after 5 hours). In addition, the PBI-GO-[BMIM][Cl] (2 wt%) membrane showed a significantly improved maximum power density of 128.45 mW cm-² at 160 °C compared to the PBI-GO-[BMIM][Cl] (2 wt%) composite membrane, which showed a maximum power density of only 106.70 mW cm-² at 25 °C. The improved performance of the PBI-GO-[BMIM][Cl] (2 wt%) membrane indicates its potential as a cost-effective and highly efficient material for HT-PEMFC applications. The use of this membrane in fuel cell technology could lead to significant cost savings in maintenance and energy consumption, while contributing to a reduction in carbon monoxide and carbon dioxide emissions, in line with industry targets for sustainable energy solutions.