Preparation of speek and speek/chitosan composite proton-exchange membranes for application in direct methanol fuel cells

Abstract

For application in direct methanol fuel cells, a series of SPEEK (sulfonated polyether ether ketone) membranes with different sulfonation degrees were tested, and a novel acid-base composite proton exchange membrane was prepared. SPEEK and chitosan were chosen as acidic and basic polyelectrolytes respectively. The properties of composite membranes, such as proton conductivity, methanol permeability, water uptake, membrane swelling and thermal stability, were tested. Although the proton conductivity reduced to some extent and the methanol permeability wasn ' t improved, the water uptake and membrane swelling were significantly improved. Particularly, after chitosan was blended with SPEEK (sulfonation degree = 71.4%) at a molar ratio of 1:5, the prepared composite membrane exhibited comparable performances with Nafion 117, and such membranes are thus promising for application in fuel cells.