One of the great challenges of this century is unquestionably energy storage. Storage is essential to make more efficient use of renewable energy sources and to enable electrical mobility. Recent developments have raised both hopes and fundamental challenges in the next generation Li batteries (including Li-ion and Li-air/Li-sulphur). Despite large research efforts, the improvement of battery performance over the last decades has been relatively small because the full potential of the storage materials is not utilized. Most of the attention has been devoted to the development of new electrode materials; however, marginal understanding has been achieved of the functioning of these materials in electrodes. The key problem is that established micro and macroscopic methods are not sensitive to the relevant time and length scales under the required in-situ conditions. Moreover, up to date calculational models do not represent the full complexity of the electrode systems.Using novel experimental and calculational approaches this project aims at fundamental understanding and improvement of Li electrodes. This requires a broad multidisciplinary approach, ranging from nuclear magnetic resonance probing nanoscopic charge transfer to in-situ neutron depth profiling exploring the mesoscopic charge transport. Calculations will combine the complex solid state diffusion in storage materials with the mesoscopic charge transport through the electrodes. By systematic variation of the electrode micro and nanostructure, this will lead to deep fundamental understanding. This project will be the first major systematic study on the fundamentals of complete electrodes. By bringing our current understanding from the level of the storage material towards complete electrodes, it will also pave the way to optimal high performance energy storage in batteries. The impact on society cannot be overstated as energy storage is a key enabler for the use of renewable energy and electrical transport.