Highlights Hierarchical polyimide (PI) nonwoven fabric is fabricated by alkali treatment. in-situ growth of magnetic particles. and "self-activated" electroless Ag plating process. Impedance matching structure by assembling Fe3O4/Ag-loaded PI nonwoven fabric (PFA) and pure Ag-coated PI nonwoven fabric (PA) induces more electromagnetic waves enter PFA/PA and be dissipated. https://chefesquipmenters.shop/product-category/merchandising-display-refrigerators/