Yang Hao, Zheng Hongfei, Yu Huaming, Qu Baihua, Chen Libao, Niu Jianmin, Chen Yuejiao
State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083, PR China.
College of Materials, Xiamen University, Xiamen, Fujian 361005, PR China.
Nanoscale. 2022 Sep 29;14(37):13722-13730. doi: 10.1039/d2nr04158h.
Engineering composite lithium (Li) metal within three-dimensional (3D) porous skeleton hosts is a feasible strategy to tackle issues of uncontrollable dendrite growth and enormous volume change on Li metal anodes. Nevertheless, the accumulative Li deposition on the top surface of the 3D skeleton remains a harsh challenge that still requires effort. Herein, we develop a rational design involving an enriched-sparse LiF gradient on a Cu foam facile magnetron sputtering to coordinate ionic and electronic conductivity. The Li ion-conductive LiF gradient guides deep, dense Li deposition within the Cu foam framework, safely preventing surface Li accumulation. As a result, the Cu foam with optimal LiF sputtering time for 40 min (Cu foam/LiF(40)) renders the best synergy of ionic and electronic conduction. Such composite Li anode in the symmetric cell achieves an ultra-long lifespan up to 1700 h at the current density of 2 mA cm with the capacity of 2 mA h cm. This work certifies the decisive significance of coordinating ionic and electronic conductivity for uniform Li deposition on 3D porous hosts and provides a simple and effective avenue to controllably deposit Li in suitable locations for long-term and high-capacity 3D Li metal anodes.
在三维（3D）多孔骨架主体中构建复合锂（Li）金属是解决锂金属阳极枝晶生长不可控和体积变化巨大问题的一种可行策略。然而，3D骨架顶面上锂的累积沉积仍然是一个严峻挑战，仍需努力解决。在此，我们通过在泡沫铜上进行简易磁控溅射，开发了一种合理设计，形成富-稀LiF梯度，以协调离子和电子传导性。锂离子传导性的LiF梯度引导在泡沫铜框架内进行深层、致密的锂沉积，安全地防止表面锂积累。结果，具有40分钟最佳LiF溅射时间的泡沫铜（泡沫铜/LiF(40)）实现了离子和电子传导的最佳协同作用。这种对称电池中的复合锂阳极在2 mA cm²的电流密度和2 mA h cm²的容量下，实现了长达1700小时的超长寿命。这项工作证明了协调离子和电子传导性对于在3D多孔主体上均匀沉积锂的决定性意义，并提供了一条简单有效的途径，可在合适位置可控地沉积锂，用于长期和高容量的3D锂金属阳极。
