Pre-lithiated Edge-enriched MoS2 nanoplates embedded into carbon nanofibers as protective layers to stabilize Li metal anodes

Abstract

Lithium metal batteries (LMBs) are favored due to their high energy densities. However, how to inhibit the growth of Li dendrites, slow down the volume expansion and realize the reversible utilization of Li anode are still big challenges for the practical feasibility. Herein, a pre-lithiated edge-enriched ultra-thin MoS2 embedded carbon nanofiber (PCNF/MoS2) framework was prepared as a protective layer to stablize Li metal anode, Mo and Li2S was in situ formed on the surface of Li foil by a facile spontaneous chemical reaction of MoS2 and Li. Among them, Mo significantly reduces the overvoltage of the Li nucleation, achieves homogeneous Li plating/stripping, guides Li deposition in the cavity of three-dimensional (3D) framework, and thus inhibits the Li dendrites growth. More importantly, Li2S, as an effective additive, facilitates uniform and robust solid electrolyte interface (SEI) formation with excellent chemical stability and high ionic conductivity, which successfully realizes stable Li anode. Thereafter, the PCNF/MoS2-Li composite anode exhibits excellent long cycle life over 750 h at 1 mA cm−2 with a capacity of 1 mAh cm−2 in the symmetrical cell. In addition, when the PCNF/MoS2-Li composite anodes were paired with LiFePO4 and LiNi0.8Co0.1Mn0.1O2 cathodes, the batteries delivered improved cycling stability and rate performance, providing a promising new avenue to achieve pratical LMBs.