Thickness‐Dependence of 2D g‐C<sub>3</sub>N<sub>4</sub> Artificial Interface Layers on Lithium Metal Deposition
Pengbo Zhai, Qianqian He, Huaning Jiang, Binyin Gao, Bo Zhang, Qian Chen, Zhilin Yang, Tianshuai Wang, Yongji Gong
Abstract
Abstract Constructing artificial interfacial layers using 2D materials with tunable physicochemical properties is a promising strategy to fabricate high‐performance lithium (Li) metal anodes. However, their structural evolution during solid‐electrolyte interphase (SEI) formation and the thickness effects on charge transport remain elusive. Herein, 2D g‐C 3 N 4 layers with varied thicknesses are developed on the surface of copper foil to evaluate the thickness effects of artificial SEI on Li metal deposition. It is demonstrated that a thin g‐C 3 N 4 layer (≈2 nm) is rapidly decomposed and fractured under the impact of Li‐ion flux, while a thick g‐C 3 N 4 layer (≈50 nm) impedes the transport of lithium ions and electrons simultaneously, hindering the Li metal deposition underneath. Notably, a g‐C 3 N 4 layer with moderate thickness (≈10 nm) dominates in‐situ generation of stable g‐C 3 N 4 /Li 3 N hybrid artificial SEI and enables fast Li‐ion transport, which induces uniform Li deposition. The lithium electrode protected by the moderate‐thickness g‐C 3 N 4 layer exhibits outstanding cycling stability with a high average Coulombic efficiency of ≈98.92% for over 380 cycles and enables stable cycling of full cell with 50% Li excess and lean electrolyte. This proof‐of‐concept study provides essential guidance for the application of 2D materials in constructing artificial SEI for Li metal anodes.