Operando Investigation on the Role of Densification and Chemo‐Mechanics on Solid‐State Cathodes.

All solid‐state batteries are desirable for a range of energy storage applications which require high energy density. Achieving a high energy density in a solid‐state battery requires the operation of an energy dense anode with a composite solid‐state cathode. Pores and/or voids within a solid state cathode are ion‐blocking and thus control over the concentration and distribution of pores in the initial electrode and cycled electrode is desirable. This study provides an understanding of the interplay between electrode microstructure and mechanics on active material utilization in solid state cathodes composed of NCM 811 and Li6PS5Cl. Decreasing the solid electrolyte particle size leads to greater active material‐electrolyte contact and less total deformation when exposed to an external load. Composite cathodes with greater compliance can potentially decrease strain between the active material and solid electrolyte, decrease delamination events and result in higher overall active material utilization and high capacity retention. [ABSTRACT FROM AUTHOR]