A novel hybrid polymeric electrolyte for MEMS-compatible micro fuel cells

摘要

Research in microfuel cells field has been mainly focused on the design and fabrication methods required to miniaturize the different elements that compose these devices. A lot of advances have been reported on the development of new materials that improve catalytic reactions, the reduction of the catalyst contents and the design of novel architectures and packaging solutions to optimize fuel cell performance at a microscale [1-3]. However, the monolithical integration of the fuel cell microparts remains still as a technological challenge, given that the incorporation of additional plates, screws or adhesives is usually required to assemble its components together and lower their contact resistance. The origin of this drawback lies on the incompatibility of polymeric electrolytes with the materials typically used in MEMS technology. This work presents a new approach towards a fully integrated micro fuel cell (patent pending [4]). The idea is based on the development of a thin hybrid electrolyte consisting of the combination of a micropatterned polydimethylsiloxane (PDMS) membrane and a proton-conducting polymer. As shown in figure 1, the PDMS membrane has an array of through-holes defined by soft lithography. These perforations are filled with a liquid solution of a proton exchange polymer (in this case, Nafion 5% in aliphatic alcohols) that solidifies after solvent evaporation and confers the membrane the required proton conductivity.