3D printing of low-tortuosity, vertically oriented anodes reconciling electronic/ionic kinetics for deep-cycling Zn batteries

Abstract

Achieving a high depth of discharge (DOD) in dendrite-free Zn anodes is essential for enhancing the energy density and cycling lifespan of zinc-ion batteries (ZIBs). However, conventional three-dimensional (3D) anodes featuring thick and disordered pore structures suffer from gradient and tortuous ion diffusion pathways, leading to mismatched electron/ionic transfer kinetics, which limit their DODs to usually lower than 40%. Herein, a low-tortuosity, N-doped 3D Zn anode is deftly crafted by 3D printing. The vertically aligned pore architecture significantly reduces electrode tortuosity, enabling rapid ion transport with shortened migration pathways. Meanwhile, the N-doped zincophilic surface substantially reduces the deposition energy barrier for uniform and compact Zn deposition even under high DODs. The resulting symmetrical cells exhibit dendrite-free cycling for 720 h at 1 mA cm⁻² and 1 mAh cm⁻² while sustaining stable plating/stripping processes at a high DOD of 61.7%. This work offers fundamental insights into the anode design philosophy for long-lasting and energy-dense ZIBs.