The stacking order, Cu/PG/MRF/PES/SS mesh, exposes Cu foil on one side of the module, allowing one to etch and remove Cu directly from the assembled module. This effectively eliminated the need to float graphene. After sealing the module, the exposed Cu was placed in contact with a cell hosting a Cu etchant (1 M FeCl3, Figure ). During etching, PG reinforced by MRF was secured in the module. The thickness of MRF film played a crucial role.