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

Molybdenum diselenide (MoSe2) has been drawing increasingly more attention due to its natural abundance, larger interlayer space (similar to 6.5 angstrom) 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. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Molybdenum diselenide (MoSe2) is gaining more attention for its natural abundance, larger interlayer space, and higher theoretical capacity, but its application is hindered by low capacity and poor cycling stability. The MoSe2/C nanoplates sheathed in N-doped carbon (MoSe2/C@NC) microstructures synthesized in this study show excellent reversible sodium/potassium ion storage capacity. The unique assembly structure of MoSe2/C@NC contributes to the synergistic effect, effectively alleviating volume expansion and improving electrical conductivity.