N-Doped Graphene Modified 3D Porous Cu Current Collector toward Microscale Homogeneous Li Deposition for Li Metal Anodes

摘要

Lithium metal is the most promising anode material for high-energy-density batteries due to its high specific capacity of 3860 mAh g(-1) and low reduction potential of -3.04 V versus standard hydrogen electrode. However, huge volume change, safety concerns, and low efficiency impede the practical applications of Li metal anodes. Herein, it is shown that the nitrogen-doped graphene modified 3D porous Cu (3DCu@NG) current collector can mitigate the above problems. The N-doped graphene, coating on the surface of 3D current collector, not only contributes to a uniform Li+ flux, but also leads to a scattered distribution of electrons throughout the surface, finally contributing to a uniform Li deposition and the improved electrochemical performance. In addition, the continuously porous structure of 3DCu@NG provides a space for the metallic Li deposition and could effectually accommodate the volume expansion during cycling. As a result, the Li-3DCu@NG anode exhibits a high areal capacity of 4 mAh cm(-2), a high Li utilization of approximate to 98%, and an ultralow voltage hysteresis of approximate to 19 mV. The multifunctional N-doped graphene modified 3D porous current collector promisingly provides a strategy for safe and high-energy lithium metal anodes.