Three-dimensional honeycomb-like MoSe2/rGO as high performance sodium ions storage materials with long cycle stability and high rate capability

Transition metal dichalcogenides (TMDs) caused widespread concern because of their possess graphite-like two-dimensional structure, which allows Na+ reversible de-intercalation between the interlayers and contributes high theoretical capacity. However, the poor conductivity and structural instability greatly limited their application to sodium ion batteries (SIBs). Herein, three-dimensional (3D) honeycomb MoSe2/rGO nanocomposites with outstanding sodium ion storage performance were prepared. The MoSe2/rGO combined the advantages of MoSe2 and rGO. The typical layered structure of MoSe2 provide Na+ diffusion pathways and sufficient active sites, while the rGO increase conductivity and alleviate structural change during Na+ insertion/extraction process. The stable discharge capacity of MoSe2/rGO reaches 300 mAh g at 0.1 A g(-1) and retains 247 mAh g(-1) after 100 times. It retains a high capacity of 214.7 mAh g(-1) at 1 A g(-1) and shows outstanding rate capability. The MoSe2/rGO//AC hybrid sodium-ion capacitors (HSIC) achieves a high capacitance of 56.7 F g(-1) at 0.1 A g(-1), it exhibits an energy density of 87.7 W kg(-1) at a power density of 208.8 W h kg(-1) and retains 50.5 W h kg(-1) when it increases to 1051.4 W kg(-1). The article brings up a novel opinion for designing porous TMDs based composites as ideal energy storage materials.