Work on your laptop on the move, search for your way with your smartphone or take pictures with your digital camera: Batteries have made the technological revolution of mobile devices possible in the first place. At the same time, they play a central role in the energy and traffic transition. In the Cluster of Excellence POLiS, we are researching batteries of the future that are more powerful, more reliable, more sustainable and more environmentally friendly than current lithium-ion batteries. POLiS is a joint Cluster of Excellence of Karlsruhe Institute of Technology (KIT), Ulm University with associated partners Centre for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) and University of Gießen (JLU).