Overview This dataset contains the 3D printable files and hardware requirements to assemble a custom compression adapter for operando neutron radiography of All-Solid-State Batteries (ASSBs). The design is engineered to adapt a standard MESTRA® C-2 dental flask clamp to securely hold a custom cylindrical ASSB cell under stack pressure while minimizing neutron beam attenuation from the surrounding hardware. This setup was successfully utilized in the research investigating lithiation gradients in composite electrodes (NMC532 / Li6PS5Cl) using high-resolution operando neutron radiography. Bill of Materials (Hardware & Modifications) To replicate this experimental setup, the following non-printed components are required: Clamp: 1x MESTRA® C-2 Clamp for flask (2-flask version with springs). Modification: The metal disc of the clamp must be sawed/machined to provide a clear, unobstructed path for the neutron beam to reach the sample. Connectors (Force Transmission): 2x Wooden dowel pins / stick connectors (M8). These interface between the 3D printed adapter and the cell caps. Operando Cell Components: 1x Cylindrical cell body machined from PEEK (polyether ether ketone). 2x Stainless Steel (SS) metal caps (Ø12 mm). Modification: The SS caps must be sawed/machined the same way as the metal disc. Electrical connectors for the battery cycling, which insert directly between the SS metal caps and the 3D-printed "Cap-cap" adaptors. 3D Printing Specifications The provided 3D models are optimized for Fused Deposition Modeling (FDM) with the following parameters to ensure the mechanical strength necessary to maintain stack pressure: Material: PETG (Polyethylene Terephthalate Glycol) Infill Density: 100% (Solid) for maximum compressive strength. Layer Height: 0.20 mm – 0.30 mm Files Included in this Repository Press-cell-v1.3mf: Complete project file containing the models and spatial arrangements. Neutrons-v1_0.8n_0.3mm_PETG_3h59m_274g.bgcode: Ready-to-print binary G-code file, specifically sliced and optimized for the Original Prusa XL 3D printer. Filename.glb: Standard binary 3D CAD models of the top and bottom adapter components for use with other slicers or for further modification. Assembly Notes Ensure the 3D-printed adapters are seated flush against the modified MESTRA clamp plates. The wooden Ø8 mm dowels are inserted into the printed adaptors and press directly against the modified Ø12 mm SS caps of the PEEK cell. Align the sawed sections of the MESTRA clamp and the SS caps parallel to the neutron beam axis to ensure an unshadowed field of view of the cell's internal components.