All‐solid‐state batteries (ASSBs) employing sulfide‐based solid electrolytes are attractive energy storage systems because of their potential advantages, such as efficient single‐ion conduction and the absence of electrolyte leakage. Although pellet‐type cells are commonly used in laboratory electrochemical testing under high stack pressure, practical application demands scalable sheet‐type configurations operable under minimal stack pressure. This study demonstrates the feasibility of sheet‐type ASSBs fabricated via slurry casting combined with cold isostatic pressing (CIP) for operation under minimal stack pressure. CIP process allows uniform densification and intimate interparticle contact, resulting in the formation of continuous lithium‐/electron‐conducting pathways within the composite electrode. In addition to the processing pressure, the composite electrode formulation with a dimensionally invariable positive electrode material, Li 8/7 Ti 2/7 V 4/7 O 2 , is systematically optimized by tuning the conductive additive content to balance ionic and electronic conduction pathways, which is a critical factor for maximizing electrochemical performance. Furthermore, the optimized composite electrodes with Li 8/7 Ti 2/7 V 4/7 O 2 show stable long‐term cycling under minimal stack pressure (<0.5 MPa). These findings demonstrate that rational microstructural design for composite electrodes through scalable processing enables high‐performance sheet‐type ASSBs with strong practical viability.
Ohno et al. (Tue,) studied this question.