MoS2-intercalated carbon hetero-layers bonded on graphene as electrode materials for enhanced sodium/potassium ion storage

MoS2 is considered as an ideal electrode material in the field of energy storage due to high theoretical specific capacity and unique layered structure. However, limited interlayer distance and poor intrinsic electrical conductivity restrict its potential real-world application. Herein, an alternately intercalated structure of MoS2 monolayer and N-doped porous carbon (NC) layer is grown on reduced graphene oxide (rGO) via a chemical intercalated strategy. The expanded interlayer distance of MoS2 (0.96 nm), enlarged by the intercalation of N-doped porous carbon layers, can enhance ion diffusion mobility, provide additional reactive sites for ion storage and maintain the stability of electrode structure. In addition, the hierarchical structures between rGO substrate and intercalated N-doped carbon layers construct a three-dimensional (3D) conductive network, which can significantly improve the electrical conductivity and the structural stability. As a result, the rGO-supported MoS2/NC electrode exhibits an ultrahigh reversible capacity and remarkable long cycling stability for sodium-ion batteries (SIBs) and potassium-ion (PIBs). Meanwhile, the as-obtained MoS2/NC@rGO electrode also delivers a superior cycle performance of 250 mAh·g−1 after 160 cycles at 0.5 A·g−1 when employed as an anode for sodium-ion full cells.