Polymer@Cu composite foils with through-hole arrays as lightweight and flexible current collectors for lithium-ion batteries

The current collector is a critical component of lithium-ion batteries (LIBs). Herein, copper-coated polymer films (P@Cu) with through-hole arrays are developed lightweight and flexible current collectors. The through-hole arrays are created by laser drilling the polyimide film substrate. P@Cu composite current collectors are fabricated by electroless Cu deposition on polyimide films with through-hole arrays, which form three-dimensional conductive paths. As the anode current collector for LIBs, P@Cu exhibit a total electrode mass-specific capacity that is 54.58 % higher than that of the commercial Cu foil. Due to the polyimide substrate, the tensile deformation of P@Cu is 6.69 % higher than that of the commercial Cu foil. After 30,000 bending cycles, the conductivity of P@Cu is only reduced by 3.39 %, while the commercial Cu foil current collectors have broken by this point. The P@Cu composite foils with through-hole arrays are high-performance lightweight and flexible current collectors for LIBs.