Spatiotemporal Ion Flux Rectification via Femtosecond Laser-Structured Biomimetic Shark-Skin Current Collectors for High-Performance Anode-Free Zinc Batteries

Abstract Anode-free zinc metal batteries (AFZMBs) offer exceptional energy density but suffer from poor reversibility caused by dendrite growth and parasitic reactions. Conventional 3D current collectors and interfacial coatings are often plagued by weak adhesion and poor scalability. Herein, a monolithic biomimetic shark-skin-patterned copper electrode (Bio-Cu) featuring hierarchical micro-grooves is fabricated via femtosecond laser ablation. This non-thermal subtractive manufacturing mitigates native surface defects and exposes a clean architecture that facilitates intimate electrolyte wetting and homogenizes interfacial ion flux. Mechanistically, the Bio-Cu electrode synergistically regulates 3D Zn 2+ transport kinetics and interfacial electric fields. This favors compact Zn deposition with an enhanced Zn(002) orientation, thereby effectively suppressing dendrite formation. Consequently, the Bio-Cu||Zn asymmetric cell delivers a lifespan exceeding 8000 cycles at 10 mA cm -2 with a 99.898% Coulombic efficiency. Notably, robust reversibility is maintained even under a stringent regime of 20 mA cm -2 at a high areal capacity of 10 mAh cm -2 . The full cell retains 80% capacity after 800 cycles at 1 A g -1 , and the assembled pouch cells reliably power an LED display screen. Furthermore, this work demonstrates that scalable biomimetic interface engineering provides a promising route to unlock the practical potential of high-energy-density metal batteries.