The main advantage originates from the adoption of a solid electrolytes instead of a flammable organic liquid. Moreover, solid electrolytes enable the integration of Li metal or its alloys enabling ultimately high energy densities. However, to reach the promised performance of solid-state batteries suitable solid electrolytes needs to be developed. For example, polymerbased electrolytes can enable cheap production of solid-state batteries by allowing current roleto-role technology, however, the low conductivity of polymer electrolytes requires temperatures above 50 °C to provide sufficient cycling performance. Furthermore, their organic nature safety remains an issue. Sulfide-based electrolytes show among the highest Li-ion conductivities ensuring satisfying rate capability of the respective solid-state battery, but their instability versus high and low voltage electrodes is a drawback with respect to energy density.