PVA-SSA-HPA mixed-matrix-membrane electrolytes for DMFCs

S. D. Bhat, A. K. Sahu, A. Jalajakshi, S. Pitchumani, P. Sridhar, C. George, A. Banerjee, N. Chandrakumar, A. K. Shukla

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Stabilized forms of heteropolyacids (HPAs), namely phosphomolybdic acid (PMA), phosphotungstic acid (PTA), and silicotungstic acid (STA), are incorporated into poly(vinyl alcohol) (PVA) cross-linked with sulfosuccinic acid (SSA) to form mixed-matrix membranes for application in direct methanol fuel cells (DMFCs). Bridging SSA between PVA molecules not only strengthens the network but also facilitates proton conduction in HPAs. The mixed-matrix membranes are characterized for their mechanical stability, sorption capability, ion-exchange capacity, and wetting in conjunction with their proton conductivity, methanol permeability, and DMFC performance. Methanol-release kinetics is studied ex situ by volume-localized NMR spectroscopy (employing "point-resolved spectroscopy") with the results clearly demonstrating that the incorporation of certain inorganic fillers in PVA-SSA viz., STA and PTA, retards the methanol-release kinetics under osmotic drag compared to Nafion, although PVA-SSA itself exhibits a still lower methanol permeability. The methanol crossover rate for PVA-SSA-HPA-bridged-mixed-matrix membranes decreases dramatically with increasing current density rendering higher DMFC performance in relation to a DMFC using a pristine PVA-SSA membrane. A peak power density of 150 mW/cm2 at a load current density of 500 mA/ cm2 is achieved for the DMFC using a PVA-SSA-STA-bridged-mixed- matrix-membrane electrolyte.

Original languageEnglish (US)
Pages (from-to)B1403-B1412
JournalJournal of the Electrochemical Society
Volume157
Issue number10
DOIs
StatePublished - 2010

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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    Bhat, S. D., Sahu, A. K., Jalajakshi, A., Pitchumani, S., Sridhar, P., George, C., Banerjee, A., Chandrakumar, N., & Shukla, A. K. (2010). PVA-SSA-HPA mixed-matrix-membrane electrolytes for DMFCs. Journal of the Electrochemical Society, 157(10), B1403-B1412. https://doi.org/10.1149/1.3465653