Sulfonated (graphene oxide/poly(ether ketone ether sulfone) (S-GO/S-PEKES) composite proton exchange membrane with high proton conductivity for direct methanol fuel cell

ABSTRACT

Sulfonated poly(ether ketone ether sulfone) (S-PEKES) was successfully prepared to obtain the currently highest degree of sulfonation of 0.744. Sulfonated graphene oxide (S-GO) was incorporated into the S-PEKES matrix to increase sulfonic groups (SO₃H) which significantly improved the proton conductivity, methanol blocking, and mechanical stability. The proton conductivity of the S-GO/S-PEKES composite membrane was enhanced up to 5.93 × 10⁻² S.cm⁻¹, which was 7 times higher than the commercial Nafion 117. S-GO exhibited additional positive effects namely the blocking of methanol passing through the membrane, leading to lower methanol crossover than Nafion 117 by two orders of magnitude and high mechanical stability.

GRAPHICAL ABSTRACT

KEYWORDS:

• Sulfonated poly(ether ketone ether sulfone) (S-PEKES)
• sulfonated graphene oxide (S-GO)
• polymer electrolyte membrane (PEM)
• direct methanol fuel cell (DMFC)

Acknowledgments

The authors would like to acknowledge the financial contributions from the Conductive and Electroactive Polymers Research Unit and the Ratchadaphiseksomphot Fund for the Postdoctoral Fellowship of Chulalongkorn University, the Thailand Research Fund (TRF), and the Royal Thai Government.

Additional information

Notes on contributors

S. Changkhamchom

Sairung Changkhamchom completed Ph.D. in Polymer Science from the Petroleum and Petrochemical College, Chulalongkorn University in 2013. She currently works as postdoctoral researcher in the field of polymer electrolyte membrane for fuel cell.

A. Sirivat

Anuvat Sirivat completed Ph.D. in Mechanical Engineering from Conell University, USA in 1985. He currently works as professor at the Petroleum and Petrochemical College, Chulalongkorn University, Bangkok, Thailand. His research fields are actuator, gas sensor, drug release system, and fuel cell membrane.