Effects of tin phosphate nanosheet addition on proton-conducting properties of sulfonated poly(ether sulfone) membranes

Shoichi Sugata*, Shinya Suzuki, Masaru Miyayama, Enrico Traversa, Silvia Licoccia

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Organic/inorganic composite membranes were prepared by dispersing nanosheets of layered tin phosphate hydrate [Sn(HPO4) 2·nH2O (SnP)] in sulfonated poly(ether sulfone) (SPES) at SnP contents of 0-40 vol.%. The stabilities and proton conductivities of SPES/SnP nanosheet (SnP-NS) composite membranes were investigated and compared with those of SPES/SnP particle (SnP-P) composite membranes. The chemical stabilities as evaluated by thermogravimetry, differential thermal analysis, and diffuse reflectance Fourier-transform infrared spectroscopy were improved in both composite membranes. The improvement in the structural stability of SPES/SnP-NS composite membranes was more evident than that in SPES/SnP-P. The results suggest that exfoliation of SnP increases the area of the SPES-SnP interface and extends the connectivity of the network of hydrogen bonds. A composite membrane containing 10 vol.% SnP-NS (SPES/SnP-NS10vol.%) showed a high conductivity of 5.9 × 10- 2 S cm- 1 at 150 °C under saturated water vapor pressure. Although less water was present in SPES/SnP-NS10vol.% than in SPES/SnP-P10vol.% or pure SPES, the conductivity of SnP-NS10vol.% was the highest among these samples at 130 °C under a high relative humidity (RH). However at a low RH, the proton-conducting property was not improved by changing the composition of the SnP-NS. These results suggest that the hydrogen-bond network operates effectively for proton conduction at a high RH, but at a low RH, the network fails to conduct as a result of a decrease in water content accompanied by structural stabilization.

Original languageEnglish (US)
Pages (from-to)8-13
Number of pages6
JournalSolid State Ionics
Volume228
DOIs
StatePublished - Nov 30 2012

Keywords

  • Fuel cell
  • Organic/inorganic nanocomposite
  • Proton conductivity
  • Tin phosphate nanosheet

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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