Lightweight Zn‐Philic 3D‐Cu Scaffold for Customizable Zinc Ion Batteries

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 H 2 ‐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.