Preparation and characterization of composite membranes with ionic liquid polymer-functionalized multiwalled carbon nanotubes for alkaline fuel cells

Abstract

Multiwalled carbon nanotubes functionalized with an imidazolium-type ionic liquid polymer, PIL(BF 4 )-MWCNTs, have been successfully prepared via in situ free radical polymerization of 1-vinyl-3methylimidazolium iodide ([VMIm][I]) and then blended with poly(2,6-dimethyl-1,4-phenylene oxide) containing imidazolium groups (PPO-MIm) in solution to fabricate composite membranes. The composite membranes were characterized by scanning electron microscopy (SEM) and the SEM images of the membranes show that the PIL(BF 4 )-MWCNTs can be homogeneously dispersed in the PPO-MIm matrix.The conductivity and mechanical properties of the composite membranes were examined. It was demonstrated that the incorporation of the PIL(BF 4 )-MWCNTs into the membranes of PPO-MIm can increase both conductivity and mechanical properties. The composite membrane containing 0.3 wt% of PIL(BF 4 )-MWCNTs (P(0.3)) exhibits a dramatic enhancement in ionic conductivity (95.3%) and tensile strength (82.9%) in comparison with the membrane without PIL(BF 4 )-MWCNTs. Therefore, this research demonstrates that the incorporation of functionalized carbon nanotubes is a facile and useful strategy for improving both ionic conductivity and mechanical properties of alkaline polymer electrolyte membranes.

Anion‐Exchange Membranes for Fuel Cells: Synthesis Strategies, Properties and Perspectives

“…This section deals with composited AEMs prepared by blending with ionic liquid 200, nano‐metal‐oxide fillers 201–206, LDH 207 or multiwalled carbon nanotube 208, and sol‐gel methods 209–212, reinforced or pore‐filling AEMs 213–233 and IPN or s‐IPN 234–239.…”

Ternary proton exchange membranes with low‐cost raw materials: Solvent type influence on microstructure development, high ionic conductivity, and ionic liquid lixiviation protection

“…This implies that IL's have the chemical behavior of a molten salt, which turns out to be highly convenient for the purpose of ionic conductivity. There are several studies that have used ILs as ionic transport agent in PEM's instead of water, which confers to the devices a higher operating temperature and high conductivity results, however, a major issue is the phenomenon of IL lixiviation, that consist in the leaching of IL from membrane matrix . In order to overcome the issue of IL lixiviation, other researchers have incorporated a tertiary phase consisting of sol–gel nanoparticles and cross‐linked polymers in order to diminish IL lixiviation, which has led to low ionic conductivity due to IL confinement and consequent mobility loss …”

Synthesis of novel copolymers based on p-methylstyrene, N,N-butylvinylimidazolium and polybenzimidazole as highly conductive anion exchange membranes for fuel cell application

“…The electrolyte membrane is a very important component in a fuel cell because of its signicant inuence on the performance. 1,2 According to the type of electrolyte, fuel cells could be classied into two categories: proton exchange membrane fuel cells (PEMFCs) where the membranes conduct protons (H + ) and anion exchange membrane fuel cells (AEMFCs) where they conduct hydroxide ions (OH À ). 3 Naon, known as state of the art, is today the most commercialized electrolyte, its proton conductivity is as high as 100 mS cm À1 at room temperature and 100% relative humidity (Naon 117), and it also possesses good mechanical properties and an excellent chemical stability.…”

“…13 This class of membranes considered as a trigger point for research in the fuel cell manufacture 2 is more and more investigated to be a good substitute to PEMFCs, 14 and great efforts to develop AEM for electrochemical application 15 have been seen in the last years due to their capability to operate in an alkaline medium 5 rather than the acidic one, where the electrochemical reactions are easier. 2 It enables the use of non-noble metals as good catalysts like silver, cobalt, or nickel for fuel-cell operation, which involves a low cost compared to the use of PEMFC. 2,13,[15][16][17] Another good property for AEM is the reduction of fuel crossover as the electro-osmotic drag goes in the opposite direction to that in PEMFCs.…”