Silica‐Modified 3D Porous Copper Current Collectors Toward Stable Lithium Metal Anodes

Abstract

Due to the ultrahigh theoretical capacity (3860 mAh g−1) and low redox potential (−3.04 V vs. standard hydrogen electrode), lithium‐metal anode is promising for the next‐generation high‐energy‐density batteries. However, the formation of Li dendrites results in the low Coulombic efficiency and safety concerns, thereby limiting the practical application. Herein, a silica‐modified three‐dimensional porous copper current collector (denoted as pCu@SiO2), which possesses a high electroactive surface area, is fabricated and then the electrochemical deposition behavior of Li metal can be significantly improved. In addition, the 3D porous structure provides sufficient volume to allow uniform Li deposition, thereby resulting in the alleviation of the volume change. Consequently, the silica layer on the surface of copper current collector enhances their interaction with Li+ ions, and promotes the uniform deposition. As a result, the fabricated pCu@SiO2||Li battery displays stable cycling performance with improved Coulombic efficiency (98%) over 200 cycles under the current density of 1 mA cm−2. Moreover, when the composite anode is assembled with a LiFePO4 cathode, the full cells exhibit a high‐specific capacity and excellent cycling stability. Herein, an insight is provided for the effective design of a 3D “Li host” for dendrite‐free Li‐metal anodes.