Synthesis and Characterization of Chitosan/κ-Carrageenan/Mesoporous Phosphotungstic Acid (mPTA) Electrolyte Membranes for Direct Methanol Fuel Cell (DMFC) Applications

Abstract

A new biopolymer based on chitosan and k-carrageenan with the addition of mesoporous phosphoric acid (mPTA) filler was used as an electrolyte membrane for Direct Methanol Fuel Cell (DMFC) applications. Electrolyte membranes of pure solution of chitosan, k-carrageenan, and various compositions of chitosan/k-carrageenan (Cs/k-Car) (80/40, 90/30, 100/20 mL) were carried out to determine the composition of chitosan/k-carrageenan optimal. The optimum chitosan/k-carrageenan membrane is Cs/k-Car 80/40 which has a tensile strength of 22.00 MPa and a methanol permeability of 14.33 x 10-6 cm2/s. Membrane Cs/k-Car 80/40 was then added with variations of mesoporous phosphotungstic acid (mPTA) filler (0.05, 0.1, 0.15, 0.2 and 0.25 %) to determine the optimum membrane electrolyte. The chitosan/k-carrageenan/mPTA 0,2% (Cs/k-Car/mPTA 0.2%) electrolyte membrane is the most optimum electrolyte membrane which has a proton conductivity of 12 x 10-3 S/cm and a methanol permeability of 7.64 x 10-6 cm2/s so it is expected to be the most suitable electrolyte membrane for DMFC application. Key words : Electrolyte membrane, chitosan, k-carrageenan, mesoporous phosphoric acid (mPTA), DMFC