Stable zn anodes with triple gradients.

Aqueous zinc-ion batteries are highly desirable for sustainable energy storage, but the undesired Zn dendrites growth severely shorts the cycle life. Herein, a triple-gradient electrode that simultaneously integrates gradient conductivity, zincophilicity and porosity is facilely constructed for dendrite-free Zn anode. The simple mechanical rolling induced triple-gradient design effectively optimizes the electric field distribution, Zn 2+ ion flux and Zn deposition paths in the Zn anode, thus synergistically achieving a bottom-up deposition behavior for Zn metals and preventing the short circuit from top dendrite growth. As a result, the electrode with triple gradients delivers a low overpotential of 35 mV and operates steadily over 400 h at 5 mA cm -2 /2.5 mAh cm -2 and 250 h at 10 mA cm -2 /1 mAh cm -2 , far surpassing the none-gradient, single-gradient and dual-gradient counterparts. The well-tunable materials and structures with the facile fabrication method of the triple-gradient strategy would bring inspiration for high performance energy storage devices. This article is protected by copyright. All rights reserved.