A Three-Dimensional (3D) Framework of Freestanding Vanadium Nitride Nanowires for Dendrite-Free and Long Life-Span Lithium Metal Anodes

Lithium (Li) metal is a promising anode candidate for high-energy-density batteries owing to its high theoretical capacity and low electrochemical potential. However, uneven Li nucleation, uncontrollable dendritic growth, infinite voltage change and even safety issues hinder its commercial application. Herein, a three-dimensional (3D) framework of freestanding vanadium nitride nanowires (VN NWs) is established as Li host for dendrite-free Li metal anode. A lithiophilic Li3N interlayer which in situ formed by the surface reaction between molten Li and VN NWs is utilized to guide a uniform Li nucleation and deposition within the skeleton, as well as avoid the dendrite formation. Meanwhile, VN NWs can decrease local current density, homogenize Li-ion flux and accommodate volume fluctuations of the anode due to its 3D structure with high electron conductivity. Thus, the corresponding composite Li metal anode delivers a long-life span of 500 cycles (1000 h) at a current density of 0.5 mA cm(-2), and exhibits lower nucleation over-potential and voltage hysteresis at different current densities from 0.5 similar to 5 mA cm(-2) in carbonate electrolyte. In conclusion, this work provides a new type of scaffold with both high electronic conductivity and excellent lithiophilicity for stable Li anodes.

Automated summary

This study utilizes a three-dimensional framework of vanadium nitride nanowires as a host for lithium metal anodes, solving issues such as dendritic growth and voltage fluctuation. The use of a lithiophilic interlayer further improves the stability and cycling lifespan of the lithium metal anode.