We propose to perform combined measurements of neutron reflectometry (NR) and impedance spectroscopy (IS) to investigate the structure/function relationship of tethered bilayer lipid membranes (tBLM) on gold substrates with incorporated membrane transport proteins. This biomimetic membrane system is the core of the bio-fuel cell that we are developing to create energy in a bio-inspired way. Previous experiments have shown that lipid bilayers with a high fraction of cardiolipin show interesting properties for electrochemical application and that the incorporation of the sodium proton antiporter protein, NhaA, is possible. We want to extend the study to different lipid compositions, protein incorporation methods and tethered lipid molecular composition to optimize the membrane-protein system in terms of stability, efficiency in protein incorporation and electrochemical properties.