(229b) Performance Characterization of Electron-Beam Lithography Patterned Nafion Membranes for Direct Methanol Fuel Cells

Direct methanol fuel cells (DMFC) are capable of directly converting methanol into DC electricity without the need for a reforming step. As a liquid fuel, methanol is easy to store and transport. However, high catalyst loading requirements and performance losses continue to limit the wide-scale adoption of the DMFC. The loss in performance results primarily from anode-to-cathode methanol crossover and the slow reaction kinetics of both methanol oxidation and oxygen reduction at the anode and cathode respectively. New materials like sulfonated poly ether ether ketone (SPEEK) and sulfonated poly sulfone (SPSf), and surface treated Nafion membranes which exhibit lower methanol crossover are being investigated as replacements to pristine Nafion for the construction of the DMFC. At present, these innovations have resulted in a tradeoff between methanol permeation and ionic conductivity which consequently lead to inefficient use of the expensive metals used to form the catalyst layers. In order to maximize the utilization of the loaded catalyst, the reaction zone should be expanded without increasing transport resistance for reactants accessing the reaction plane. To achieve this objective, the membrane-electrode interface could be restructured to possess a larger interfacial area by creating features on the Nafion membrane. We present the use of electron beam lithography coupled with dry etching strategies for patterning Nafion and creating nano/micro-structured membrane electrode assemblies (MEA). EBL provides a convenient tool for rapid prototyping and assessing feature sizes beyond the resolution of conventional light-based lithographic techniques. In this communication we present the performance characterization of the electron beam patterned membranes for DMFCs.