Studies on a novel anion‐exchange membrane based on chitosan and ionized organic compounds with multiwalled carbon nanotubes for alkaline fuel cells

Abstract

In this work, a novel hydroxyl-anion-conducting membrane composed of chitosan (CTS), an ionized organic compound ([QAIM]OH), and hydroxylated multiwalled carbon nanotubes (MWCNTs-OH) has been fabricated through a blending-casting method assisted by a glutaraldehyde (GA) crosslinking process that can improve the mechanical properties of the membrane effectively. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy revealed that [QAIM]OH and MWCNTs-OH were successfully introduced into the CTS matrix. A chemical crosslinking reaction between CTS and GA could be confirmed by FTIR, X-ray photoelectron spectroscopy, and contact angle tests. By tuning the mass fraction of [QAIM]OH and MWCNTs-OH in the membrane, the maximum OH 2 conductivity (5.66 3 10 23 S cm 21 at room temperature) could be achieved for the composition CTS:[QAIM]OH (1:0.75 in mass) blend doped with 3% MWCNTs-OH. At a current density of 59.9 mA cm 22 , a membrane electrode assembly fabricated with the CTS/[QAIM]OH/ MWCNTs-OH membrane (1:0.5/3%) achieved a power density of 31.6 mW cm 22 in a H 2 /O 2 system at room temperature. Under the condition of intermediate temperature (100-140 8C) without water, the conductivities of the membranes increased with increasing temperature and the amount of [QAIM]OH, which acted as an ionic liquid in the membrane, indicating that the ionic transport behaviors could still be occurring.

Anion Exchange Membranes with 1D, 2D and 3D Fillers: A Review

“…Only a few examples of composites containing chitosan and CNTs are present in the literature. CS was used as a matrix for MWCNTs-OH and ionic liquids quaternized with isoquinoline moieties bearing ammonium groups [29]. Quaternized chitosan (QCS) and functionalized CNTs were prepared with the aim to improve the mechanical properties [30].…”

Alkaline membrane fuel cells: anion exchange membranes and fuels

“…Water clusters have an important inuence on the transport of OH À anions through the AEM, which means that an appropriate increase in the adsorption of water can improve the ionic conductivity through the membrane, yet a substantial increase in the adsorption of water can have a negative impact on the effectiveness of the membrane. 121 The Grotthuss mechanism. The Grotthuss mechanism is considered as the main transport mechanism for the transport of OH À anions through AEM membranes.…”

“…The performances of some natural based AEMs have also been studied, including a composite membrane from 2 wt% quaternised CNC and quaternised PPO, which was prepared by Cheng et al 139 The H 2 / O 2 cell performance of such a membrane showed an impressive peak power density of 392 mW cm À2 at 60 C with no backpressure on the feed gases and a Pt/C cathode and PtRu/C anode. Zhou et al 121 fabricated a novel OH À conducting membrane composed of CS, an ionised organic compound and hydroxylated multiwalled carbon nanotubes cross-linked by glutaraldehyde. H 2 /O 2 single cell tests have shown a power density of 31.6 mW cm À2 at room temperature with Pt/C catalysts.…”

Crosslinked anion exchange membrane with improved membrane stability and conductivity for alkaline fuel cells

“…As a core component of AEMFCs, the performance of AEM has a crucial influence on the stable operation of AEMFCs. However, due to the limitations of technology, AEMs still have some disadvantages, such as low electrical conductivity, poor steric stability, and inferior alkaline stability …”

“…However, due to the limitations of technology, AEMs still have some disadvantages, such as low electrical conductivity, poor steric stability, and inferior alkaline stability. 12,13 Many polymers have been used in the preparation of AEMs, for example, polysulfone (PSF), 14 poly(ether sulfone), 15 poly(ether ether ketone), 16 polystyrene, 6 and poly(ether imide). 17 The most common functional group is the quaternary ammoniums group, which is usually introduced into the polymer backbone by chloromethylation or bromination and functionalization.…”