Dendrite-free and minimum volume change Li metal anode achieved by three-dimensional artificial interlayers

Abstract

Li metal anodes are considered as the “Holy Grail” for the next-generation Li metal batteries due to their unique properties such as high specific capacity, low potential, and light weight. However, Li metal anodes have serious challenges to be overcome, including Li dendrite growth, “dead Li” layer formation, and infinite volume change during the repeated plating and stripping. Herein, we extend the “interlayer” concept to the application of Li metal anodes and rationally design a bi-functional interlayer. The vertical nitrogen-doped carbon nanotubes (NCNTs) are grown on the carbon fibre of carbon papers (CP) to obtain a 3D interlayer for Li metal. Firstly, we demonstrate the relationship between surface area and electrochemical performances on the 3D structure by controlling the growth time of NCNTs. Remarkably, the Li-CP-NCNTs composite electrode can deliver very stable performances over 600 h (~ 900 cycles) and 250 h (~ 750 cycles) at the ultrahigh current densities of 5 mA cm−2 and 10 mA cm−2, respectively, which is two times higher than that of the cell using pristine CP interlayers. Meanwhile, with a high capacity of 3 mAh cm−2, the Li metal anode with CP-NCNTs interlayer delivers a long life time of over 350 h at a current density of 3 mA cm−2. The morphologies of both Li foil and CP-NCNTs interlayers display dendrite-free deposition and minimum volume change. We believe that these new findings could open a new avenue for achieving long life time, dendrite-free and minimal volume change Li metal anodes.