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Keywords:

  • anode materials;
  • electrochemistry;
  • graphene;
  • lithium-ion batteries;
  • molybdenum oxide

Abstract

Crumpled graphene–MoO2 composite powders are directly prepared by means of spray pyrolysis and from a stable graphene oxide colloidal solution in the presence of Mo ions. The crumpled graphene–MoO2 composite powders are transformed into MoO3-based composite powders after post-treatment at 300 °C. The transmission electron microscopy and dot-mapping images of the post-treatment composite powders show uniform distribution of MoO3 nanocrystals in the crumpled graphene powders. The two typical D and G bands of graphene are observed at 1350 and 1590 cm−1, respectively, in the Raman spectrum of the graphene–MoO3 composite. In addition, the crumpled graphene–MoO3 powders exhibit superior electrochemical behavior compared to that of pure MoO3 as an anode material for lithium-ion batteries. The initial discharge capacities of the graphene–MoO3 composite and bare MoO3 powders at a current density of 2 A g−1 are 1490 and 1225 mA h g−1, respectively. The capacity retention of the graphene–MoO3 composite is 87 % after the first cycle, whereas that of bare MoO3 is 47 %, as measured after 100 cycles. The reversible discharge capacity of the graphene–MoO3 composite decreases slightly from 1228 to 845 mA h g−1 as the current density increases from 0.5 to 3 A g−1.