High efficiency, a long operating time thanks to energy-rich fuels and easy refilling make fuel cells the technology of the future for the powering of electrical appliances. Due to its high energy density and low toxicity, ethanol is the ideal fuel to give fuel cells mass-market appeal. Direct ethanol fuel cells (DEFCs) can convert ethanol electrocatalytically directly at the electrode (Fig. 1). A total of six Fraunhofer institutes are working together on developing this technology at both component and system levels. The role of the IGB is the development of innovative membranes for DEFCs.