Solid-State Synthesis of Layered MoS2 Nanosheets with Graphene for Sodium-Ion Batteries

Abstract

Sodium-ion batteries have potential as energy-storage devices owing to an abundant source with low cost. However, most electrode materials still suffer from poor conductivity, sluggish kinetics, and huge volume variation. It is still challenging to explore apt electrode materials for sodium-ion battery applications to avoid the pulverization of electrodes induced by reversible intercalation of large sodium ions. Herein, we report a single-step facile, scalable, low-cost, and high-yield approach to prepare a hybrid material; i.e., MoS2 with graphene (MoS2-G). Due to the space-confined effect, thin-layered MoS2 nanosheets with a loose stacking feature are anchored with the graphene sheets. The semienclosed hybrid architecture of the electrode enhances the integrity and stability during the intercalation of Na+ ions. Particularly, during galvanostatic study the assembled Na-ion cell delivered a specific capacity of 420 mAhg−1 at 50 mAg−1, and 172 mAhg−1 at current density 200 mAg−1 after 200 cycles. The MoS2-G hybrid excels in performance due to residual oxygen groups in graphene, which improves the electronic conductivity and decreases the Na+ diffusion barrier during electrochemical reaction, in comparison with a pristine one.