Preparation of Ultra‐Thin Copper Foil for Enhancing the Lithium Metal Batteries Properties by Recycling Waste Printed Circuit Boards

. Furthermore, the Li@Cu||LFP cells retain 89.7% capacity after 200 cycles at room temperature, and the Cu||LFP (anode-free) cells with Ut-Cu show 68.8% capacity retention after 100 cycles, with the mass energy density increasing 39.4% compared with the commercial electrolytic copper foil (Com-Cu). Moreover, the average copper recovery rate of WPCBs can reach as high as 67.7%, conducive to environmental protection and turning waste into treasure.