Novel Chitosan-Based Composite Membranes for Fuel Cells Applications

Abstract

Chitosan based membranes were fabricated in this work. Ionic liquids (ILs), namely, 1-Hexyl-3-methylimidazolium tricyanomethanide [HMIM] [TCM], Diethylmethylammonium methanesulfonate [DEMA] [OMs], were used to modify the chitosan. The membranes were assessed for their potential application in proton exchange membrane (PEMs) fuel cells. Chitosan is one of the attractive choices of membrane polymer materials because of its reasonable conductivity and stability. The membranes were synthesized by solution casting method followed by a solvent drying procedure. These were then cross-linked with an ionic solution containing sodium hydroxide to enhance the mechanical strength and the flexibility of the membranes. The inherent low proton conduction value of chitosan polymer was improved by modifying it with ILs, namely, [HMIM] [TCM] and [DEMA] [OMs]. Preliminary proton conductivity results obtained via the electrochemical impedance spectroscopy study revealed promising proton conductivities of the prepared membranes. The proton conductivity of the chitosan-based membrane was increased from 8.4x10-4to 1.2x10-2S/cm and 1.1x10-2S/cm when a 30 wt.% [HMIM][TCM] and 100 wt.% [DEMA][OMs] were added, respectively. These membranes have low cost, high proton conductivities, and are eco-friendly. These properties make them excellent candidates for fuel cells applications.