Axel Gross Universität Ulm In spite of its technological relevance in the energy conversion and storage, our knowledge about the microscopic structure of electrochemical electrode-electrolyte interfaces and electrical double layers in batteries and fuel cells is still rather limited. The description of these interfaces from first principles is hampered by the theoretical and computational challenges associated with a proper treatment of varying electrode potentials and the presence of liquid electrolytes requiring the determination of thermal averages. Despite these obstacles, there has already significant progress been made in the first-principles modeling of electrochemical electrode-electrolyte interfaces. In this contribution, I will present our attempts [1-6] to contribute to this progress by systematically increasing the complexity of the considered systems. Thus we have addressed thermal disorder by performing ab initio molecular dynamics simulations [1], the DFT water description has been improved by including dispersion effects [2], varying electrode potentials have been considered in a numerical setup with an explicite counter electrode [3], water structures at stepped electrodes have been studied [4], and the fact that in equilibrium electrodes are typically covered by adsorbates has been taken into account [5]. Furthermore, first attempts to include a realistic description of the anion adsorption on electrode-electrolyte interfaces [6] will be discussed. Finally, studies addressing the structure of electrode-electrolyte interfaces relevant for batteries will be discussed [7,8]. References [1] Schnur, S. and Groß, A. New J. Phys. 2009, 11, 125003. [2] Tonigold, K. and Groß, A., J. Comput. Chem. 2012, 33, 695. [3] Schnur, S. and Groß, A. Catal. Today 2011, 165, 129. [4] Lin, X. and A. Groß, A., Surf. Sci. 2012, 606, 886. [5] Roman, T. and Groß, A., Catal. Today 2013, 202, 1838. [6] Roman, T. and Groß, A., Phys. Rev. Lett. 2013, 110, 156804. [7] Buchner, F. et al., ACS Nano 2013, 7, 7773. [8] Hörmann, N. and Groß, A. J. Solid State Electrochem. 2013, DOI: 10.1007/s10008-013-2189-x