Catholyte‐Free Composite Cathodes Break the Energy Density Barrier of All‐Solid‐State Lithium Batteries

ABSTRACT The gravimetric and volumetric energy densities of 500 Wh kg –1 and 1000 Wh L –1 are considered as the “holy grail” target values for the development of all‐solid‐state lithium pouch batteries. However, the substantial amount of non‐energy‐providing deformable catholytes in conventional catholyte‐based composite cathodes limits the theoretical values of the energy densities to approximately 400 Wh kg –1 and 900 Wh L –1 , respectively. Here, we propose a design strategy for catholyte‐free composite cathodes using deformable halide cathode for the replacement of the non‐energy‐providing catholyte to increase the energy density. Based on this strategy, the gravimetric and volumetric energy densities of all‐solid‐state lithium pouch batteries improve by an average of 30% and 11%, respectively. Compared with conventional catholyte‐based composite cathodes, the energy densities of these batteries now exceed 500 Wh kg –1 and 1000 Wh L –1 , respectively. The catholyte‐free composite cathode design is expected to facilitate the industrialization of high‐energy‐density all‐solid‐state lithium pouch batteries.