Pressing Mode Determines Densification Uniformity and Dimensional Stability in Sulfide Solid-State Batteries
Year: 2026
Type: preprint
Abstract: Pressure-assisted densification is essential for manufacturing sulfide solid-state batteries because electrochemical performance critically depends on intimate solid–solid contact within the electrode stack. However, how the applied stress state governs the co-densification of mechanically dissimilar layers and their electrochemical functionality remains poorly understood. Here, we investigate the pressure-assisted consolidation of Li6PS5Cl separator/composite cathode bilayers under uniaxial and isostatic loading. Despite the contrasting mechanical response of the compliant separator and rigid composite cathode, all processing routes follow the same three-stage ceramic compaction mechanism. Isostatic loading and elevated temperature do not alter this mechanism but substantially improve densification efficiency and, more importantly, suppress the radial strain and center-to-edge density gradients inherent to uniaxial processing. The resulting lateral deformation compromises dimensional stability, which becomes increasingly critical for large-area electrodes and multilayer stacking. At the same time, locally under-densified edge regions provide mechanically weak, porous pathways for metal filament propagation and subsequent short circuiting. Warm isostatic pressing suppresses both lateral deformation and spatial densification heterogeneity, demonstrating that these limitations can be overcome by controlling the stress state during consolidation. These findings establish that a scalable densification process must provide not only sufficient average density, but homogeneous consolidation across the complete electrode while preserving its geometry, providing processing criteria for the development of large-area solid-state batteries.
Source: ChemRxiv
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7208773081