Ultra-Stable 3D-Printed Zn Powder-Based Anode Coated with a Conformal Ion-Conductive Layer

Zinc powder is promising for rechargeable zinc-ion batteries due to its low cost and well tunability. However, the corrosion and the dendrite growth are much more serious in zinc powder than those in conventional zinc foils, which poses a significant obstacle to wide utilization. Herein, an ultra-stable Zn powder-based anode constructed by coating a conformal ion-conductive hydrogel layer on 3D-printed Zn scaffolds is reported. The interconnected hydrogel effectively redistributes the zinc ion flux and homogenizes the surface electric field, while the 3D architecture alleviates the stress from volume change at high current densities/capacities. As a result, the 3D Zn powder-based symmetric cell steadily works for over 4700 h (>6 months) at a high current density/capacity of 5 mA cm⁻²/5 mAh cm⁻², which is superior to previously reported Zn powder-based anodes and bare Zn foil, providing a promising route for practical applications of low-cost and large-scale zinc-ion batteries.