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

A new biopolymer based on chitosan and κ-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 from a pure solution of chitosan, κ-carrageenan, and various compositions of chitosan/κ-carrageenan (Cs/κ-Car) (80/40, 90/30, 100/20 mL) were carried out to determine the composition of chitosan/κ-carrageenan optimal. The optimum chitosan/κ-carrageenan membrane is Cs/κ-Car 80/40, with a tensile strength of 22.00 MPa. Membrane Cs/κ-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 Cs/κ-Car/mPTA 0.2% electrolyte membrane is the most optimum electrolyte membrane, which has a proton conductivity of 12×10^–3 S cm^–1 and methanol permeability of 7.64×10^–6 cm² s^–1, so it is expected to be the most suitable electrolyte membrane for DMFC application.