In-situ growth of vertically aligned MoS2 nanowalls on reduced graphene oxide enables a large capacity and highly stable anode for sodium ion storage

Abstract

MoS2 has attracted remarkable attention, attributed to its high specific capacity and graphite-like structure. However, the low rate capability and poor cycle stability are two major obstacles that hinder the practical application of MoS2 in sodium-ion batteries (SIBs). Herein, MoS2 grows vertically on the surface of reduced graphene oxide (rGO) and forms a nanowall structure by electrostatic attraction, whose growth has been induced by cetyltrimethyl ammonium bromide (CTAB). This unique nanowall has a large specific surface area, which not only exposes plenty of active sites and shortens the diffusion distance of Na+, but also improves the electronic conductivity and structural stability. Meanwhile, detailed kinetic analysis is also employed to explain the Na+ storage behavior. The pseudo capacitance-dominated contribution ensures a more stable and much faster Na+ storage. Therefore, the MoS2@rGO composite displays excellent electrochemical performance. For example, the capacity of the MoS2@rGO composite can still be maintained at 571.5 mA h g−1 with 94.1% retention, after 100 cycles at 0.1 A g−1. Impressively, MoS2@rGO still exhibits a considerable capacity of 124 mA h g−1 at an ultra-high current density of 40 A g−1. The excellent performance makes the MoS2@rGO material a prospective electrode for use in large-scale SIBs.