Figure : Schematic illustration of the generalized lithium solid-state battery (SSB) cell concept. Bottom graphs show the analysis of the partial lithium-ion conductivity (σ ef f ) and the assessment of the tortuosity factor (κ) based on the weight fraction of the SE (Solid Electrolyte), which correlates with the volume fraction (ε). The graphs are taken from. Developing solid-state batteries (SSBs) requires thick cathode architectures and low solid electrolyte (SE) fractions in order to achieve high energy density, as illustrated in Figure .