It has recently been demonstrated that reducing the volume fraction of the solid electrolyte in the composite significantly decreases the effective ionic conductivity of inorganic SEs compared to their bulk conductivity, as shown in Figure . In addition, solid electrolytes need effective conductivities above 10 mS cm -1 to achieve fast rates in cathode composites. If completely solid cathodes cannot meet performance or long-term operation requirements, hybrid electrolytes or liquid electrolytes (LEs) may be employed, so-called almost solid electrolytes.