Abstract
In this work, multi-walled carbon nano-tubes (CNTs) were modified with pendant Fe3O4 nanoparticles and polyvinyl alcohol (PVA) polymer chains. These functionalized CNTs (FeCNT) were incorporated into a PVA solution and used to prepare a cast film. The use of the pendant Fe3O4 nanoparticles resulted in a loose crystal structure with low crystallinity for the PVA matrix. With an increased fractional free volume, the water solubilities and diffusivities were enhanced in the FeCNT-containing composite membranes. The methanol permeability was reduced in the PVA-FeCNT sample. The PVA and PVA-FeCNT films were doped with a potassium hydroxide (KOH) solution to prepare hydroxide-conducting solid electrolytes. The ionic conductivity of the KOH-doped PVA-FeCNT composite membrane was improved by the FeCNT addition. This improvement was ascribed to the increased polymeric amorphous region with the ionic conducting micro-channels provided by the FeCNT. These electrolytes were used in direct methanol alkaline fuel cells. An open-circuit potential and a peak power density of 0.87V and 87.8mWcm-2, respectively, were obtained using a 2M methanol fuel in 6M KOH at 60°C with the PVA-based electrolyte containing 0.15% FeCNT. This peak power density was more than double the value observed without the FeCNT incorporation.
Original language | English |
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Pages (from-to) | 41-49 |
Number of pages | 9 |
Journal | Journal of Membrane Science |
Volume | 444 |
DOIs | |
State | Published - 01 10 2013 |
Keywords
- Cell performance
- Conductivity
- Direct methanol alkaline fuel cell (DMAFC)
- FeO nanoparticles
- Functionalized carbon nano-tubes