Interface Design Considering Intrinsic Properties of Dielectric Materials to Minimize Space-Charge Layer Effect between Oxide Cathode and Sulfide Solid Electrolyte in All-Solid-State Batteries

摘要

Introducing dielectric materials is a promising approach to mitigate spacecharge-layer (SCL) formation, which negatively affects the electrochemicalperformance of sulfide-based all-solid-state batteries (ASSBs). Most previousstudies have focused on mitigating SCL formation by introducing dielectricmaterials, overlooking the fact that significant dielectric properties such asthe dipole moment direction and the magnitude of the dielectric constantcan influence SCL formation. To clarify the unclear mechanism of dielectricmaterials mitigating SCL formation, paraelectricity, ferroelectricity, and themagnitude of the dielectric constant are investigated to determine their effecton SCL formation. Paraelectric materials possessing no permanent dipolemoment can effectively mitigate the SCL formation better than ferroelectricmaterial with strong permanent dipole moment because of the intrinsiccharacteristics of the paraelectric material, in which the dipole moment canbe aligned along the direction of the electric field applied inside of ASSB.Furthermore, paraelectric materials with a larger dielectric constant havea greater effect in mitigating SCL effect than paraelectric materials with asmaller dielectric constant. Thus, these properties should be consideredin cathode-solid-electrolyte interface design. This study considers relevantdielectric material characteristics that had not been considered previously,suggesting a new paradigm for optimizing the interfacial resistance of sulfidebasedASSBs originating from SCL formation.