Effect of imidazole-doped nanocrystalline cellulose on the characterization of Nafion films of fuel cells

BACKGROUND In this study, we have fabricated a polymeric material (CNC/Im) consisting of cellulose nanocrystals (CNC) synthesized from Vietnamese rice husk biomass and imidazole (Im) dopant. Next, we propose a new approach to fabricate Nafion/CNC/imidazole (NCI) composite materials by mixing the CNC/imidazole hybrid into Nafion matrix using a very simple solution method, and then investigating the influence of CNC/Im on the properties of NCI membranes. RESULTS Electrochemical impedance spectroscopy (EIS) analysis showed that the proton conductivity of the CNC/Im membrane depends on the linked molar ratio of Im to glucose units (denoted by the n index), and this value is higher than that of pure CNC by a factor of 6. Differential thermal analysis (DSC) showed that the value of the n index is around 1:17 with all the content ratios between CNC and Im. Next, we synthesized composite materials based on CNC/Im and Nafion 117 (NCI) and investigated the influence of CNC/Im on the properties of NCI membranes. The results demonstrated that proton conductivity of the NCI membranes changes according to the content of Nafion 117, and reaches the highest value of 6.19 x 10(-4) S m(-1) with an Nafion 117/(CNC/Im) ratio of 2:1. It was observed that the CNC fiber bundles were surrounded by a polymer layer and no phase separation occurs in the scanning electron micrographs of NCI materials. CONCLUSIONS These results indicate that the prepared NCI composites will be potential materials for eco-friendly fuel cell operating in low humidity conditions. (c) 2021 Society of Chemical Industry (SCI).

Automated summary

The study fabricated a polymeric material consisting of cellulose nanocrystals and imidazole, and proposed a new approach to fabricate composite materials by mixing the hybrid into a Nafion matrix. The results showed improved proton conductivity and potential for eco-friendly fuel cell operation in low humidity conditions.