Institute of Flexible Electronics, Northwestern Polytechnical University, Xi'an, 710072, China.
Key laboratory of Flexible Electronics of Zhejiang Provience, Ningbo Institute of Northwestern Polytechnical University, 218 Qingyi Road, Ningbo, 315103, China.
Adv Mater. 2023 Feb;35(6):e2207573. doi: 10.1002/adma.202207573. Epub 2022 Dec 18.
Aqueous zinc-ion batteries are highly desirable for sustainable energy storage, but the undesired Zn dendrites growth severely shortens the cycle life. Herein, a triple-gradient electrode that simultaneously integrates gradient conductivity, zincophilicity, and porosity is facilely constructed for a dendrite-free Zn anode. The simple mechanical rolling-induced triple-gradient design effectively optimizes the electric field distribution, Zn 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 /2.5 mAh cm and 250 h at 10 mA cm /1 mAh cm , far surpassing the non-gradient, single-gradient and dual-gradient counterparts. The well-tunable materials and structures with the facile fabrication method of the triple-gradient strategy will bring inspiration for high-performance energy storage devices.
水系锌离子电池因其在可持续储能方面的巨大潜力而备受关注，但不理想的锌枝晶生长严重缩短了电池的循环寿命。在本文中，我们设计并制备了一种简便的三重梯度电极，该电极同时集成了梯度电导率、亲锌性和多孔性，可用于无枝晶锌阳极。简单的机械滚压诱导的三重梯度设计可以有效地优化锌阳极中的电场分布、锌离子通量和锌沉积路径，从而协同实现锌金属的自下而上的沉积行为，并防止顶部枝晶生长导致的短路。因此，具有三重梯度的电极表现出低过电势（35 mV），在 5 mA cm /2.5 mAh cm 下稳定运行超过 400 小时，在 10 mA cm /1 mAh cm 下稳定运行超过 250 小时，远远超过非梯度、单梯度和双梯度对照电极。这种具有良好可调性的材料和结构以及简便的三重梯度策略的制备方法，为高性能储能器件带来了新的启发。
