In situ generation of Li3N concentration gradient in 3D carbon-based lithium anodes towards highly-stable lithium metal batteries

The uncontrolled dendrite growth of lithium metal anodes (LMAs) caused by unstable anode/electrolyte interface and uneven lithium deposition have impeded the practical applications of lithium metal batter-ies (LMBs). Constructing a robust artificial solid electrolyte interphase (SEI) and regulating the lithium deposition behavior is an effective strategy to address these issues. Herein, a three-dimensional (3D) lithium anode with gradient Li3N has been in-situ fabricated on carbon-based framework by thermal dif-fusion method (denoted as CC/Li/Li3N). Density functional theory (DFT) calculations reveal that Li3N can effectively promote the transport of Li' due to the low energy barrier of Li' diffusion. As expected, the Li3N-rich conformal artificial SEI film can not only effectively stabilize the interface and avoid parasitic reactions, but also facilitate fast Li' transport across the SEI layer. The anode matrix with uniformly dis-tributed Li3N can enable homogenous deposition of Li, thus preventing Li dendrite propagation. Benefiting from these merits, the CC/Li/Li3N anode achieves ultralong-term cycling for >1000 h at a cur-rent density of 2 mA cm-2 and dendrite-free Li deposition at an ultrahigh rate of 20 mA cm-2. Moreover, the full cells coupled with LiFePO4 cathodes show extraordinary cycling stability for >300 cycles in liquid -electrolyte-based batteries and display a high-capacity retention of 96.7% after 100 cycles in solid-state cells, demonstrating the promising prospects for the practical applications of LMBs.(c) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.