Microstructures constructed by MoSe2/C nanoplates sheathed in N-doped carbon for efficient sodium (potassium) storage

Abstract Molybdenum diselenide (MoSe2) has been drawing increasingly more attention due to its natural abundance, larger interlayer space (~ 6.5 A) and higher theoretical capacity (422 mA h/g). Nevertheless, the low capacity and the poor cycling stability greatly hinder their application. Here, microstructures constructed by MoSe2/C nanoplates sheathed in N-doped carbon (MoSe2/C@NC) were synthesized by co-precipitation approach and subsequent annealing treatment with selenium powder. MoSe2/C@NC electrode shows the reversible sodium/potassium ion storage capacity of 362 and 310 mA h/g at 0.1 A/g, respectively. In SIBs, the capacity retains 237 mA h/g after a long-term cycling (500 cycles) at 1 A/g. In addition, it is worth noting that the capacity also retains 212 mA h/g at 1 A/g over 100 cycles in PIBs. The excellent performances for sodium and potassium ions storage are credited to the synergistic effect of unique assembly structure of MoSe2/C@NC, which can effectively alleviate volume expansion, and improve the electrical conductivity of MoSe2.