Hydrothermal synthesis of Co-doped-MoS2/reduced graphene oxide hybrids with enhanced electrochemical lithium storage performances

Abstract

This work reports a facile one-pot hydrothermal route to fabricate Co-doped- MoS2/reduced graphene oxides (RGO) hybrids. The effects of Co-doping on the morphology, microstructure and electrochemical lithium storage performance of these hybrids are investigated. It is demonstrated that the rational Co-doping can change the morphologies and microstructures of the hybrids. Especially, the Co-doped-MoS2/RGO-2 prepared with 1:4 mol ratio of CoCl2 to Na2MoO4 in the hydrothermal solution shows that the numerous Co-doped MoS2 layers with shorter crystal fringes and more defect sites are well anchored on the surface of RGO, resulting in the significantly enhanced electrochemical performance for reversible lithium storage. In comparison with the MoS2/RGO, the Co-doped-MoS2/RGO-2 can not only deliver much larger reversible capacity of 1236 mAh g−1 with good cyclic stability at the current density of 100 mA g−1, but also exhibit significantly enhanced high-rate capability of 895 mAh g−1 at a high current density of 1000 mA g−1. The Co-doped-MoS2/RGO-2 also shows much higher Coulombic efficiency of 89.2% at the first cycle than MoS2/RGO (67.2%). The greatly enhanced electrochemical performance is ascribed to its robust heterostructure by hybridizing of Co-doped MoS2 layers and RGO sheets.