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Abstract:
Porous metal current collectors (CCs) serve as key component for aqueous Zn-ion batteries (AZIBs). Herein, a lightweight 3D-Cu architecture with customizable geometries is developed to enable reversible Zn-metal cycling. The 3D-Cu is prepared by 3D-printing a crosslink-able polymer scaffold followed by Cu-metallization. The printed architecture is optimized to endow 3D-Cu with electric conductivity that is on-par with commercial Cu foam, but can reduce ≈80% of the weight and consumption of Cu. A Zn-philic graphene (Gr) coating is adopted to promote uniform and (002)-preferred Zn growth onto the 3D-Cu surface, creating a 3DP-Cu@Gr architecture that induces conformal Zn-deposition and greatly suppressed H2-evolution reaction. The 3DP-Cu@Gr||Zn shows stable 700 cycles at 4 mA cm−2 and 2 mAh cm−2, with coulombic efficiency >99.6%. Zn-loaded 3D-electrodes enable symmetrical cells with stable 300 h cycling at 10 mA cm−2, delivering a specific accumulated capacity of 86.7 Ah g−1. This represents an unprecedented combination of cycle stability, high charge rate, and electrode lightweight. The all-printed pantacle-shape full pouch cells (3.6 mAh) exhibit 91.4% capacity retention after 200 cycles at 1 C. Possessing unusual design freedom, this strategy demonstrates a pathway for developing lightweight Cu CCs and customizable high-energy AZIBs.
