Dry Compressible Anode Interlayer Design Enabling All-Solid-State Batteries at Low Stack Pressure

All-solid-state batteries (ASSBs) using lithium (Li) metal anodes are a promising next-generation energy storage technology with improved safety and energy density. However, their cycling performance is limited by the propensity of Li to plate unevenly at the interface between the Li metal anode and the solid-state electrolyte (SSE) surface, leading to void formation, increased local current densities, and impedance escalation. Silver–carbon (Ag–C) anode interlayers, usually prepared from solvent-based approaches, have recently shown promise to promote homogeneous Li plating and improve ASSB cell performance. Here, we report a silver-holey-graphene (Ag-hG)-based interlayer that can be fabricated from facile dry compression without the use of solvents or binders, which is highly desirable for ASSB component fabrication owing to the unique dry compressible properties of hG. The Ag-hG interlayer simultaneously improves cyclability and rate performance of ASSBs at low stack pressures. hG is also used as the electrically conductive scaffold for dry-pressed cathodes featuring lithium nickel manganese cobalt oxide (NMC) mass loadings as high as 100 mg cm–2, whereas mechanical failure is expected if using traditional slurry-based methods for cathode fabrication. The dry-pressed Ag-hG interlayer, coupled with the dry-pressed NMC cathode, enables high-performance ASSB coin cells that operate at low stack pressure (<0.5 MPa) provided only by the spring insert. A cell featuring the interlayer maintains 65% of their capacity after 100 cycles at 2C, compared to just 16% without the interlayer. In addition, in-depth stack pressure and impedance evolution experiments are conducted to evaluate the improvement mechanism from the interlayer. The designed Ag-hG interlayer and the high mass loading cathode architecture with the hG scaffold, both fabricated from dry compression, introduces a promising low-cost method to create high-performance thick electrodes for low pressure capable ASSBs.