Multicomponent metal oxide hollow-nanosphere decorated reduced graphene oxide (rGO) composite powders are prepared by spray pyrolysis with nanoscale Kirkendall diffusion. The double-layer NiFe2O4@NiO-hollow-nanosphere decorated rGO composite powders are prepared using the first target material. The NiFe-alloy-nanopowder decorated rGO powders are prepared as an intermediate product by post-treatment under the reducing atmosphere of the NiFe2O4/NiO-decorated rGO composite powders obtained by spray pyrolysis. The different diffusion rates of Ni (83 pm for Ni2+) and Fe (76 pm for Fe2+, 65 pm for Fe3+) cations with different radii during nanoscale Kirkendall diffusion result in multiphase and double-layer NiFe2O4@NiO hollow nanospheres. The mean size of the hollow NiFe2O4@NiO nanospheres decorated uniformly within crumpled rGO is 14 nm. The first discharge capacities of the nanosphere-decorated rGO composite powders with filled NiFe2O4/NiO and hollow NiFe2O4@NiO at a current density of 1 A g-1 are 1168 and 1319 mA h g-1, respectively. Their discharge capacities for the 100th cycle are 597 and 951 mA h g-1, respectively. The discharge capacity of the NiFe2O4@NiO-hollow-nanosphere-decorated rGO composite powders at the high current density of 4 A g-1 for the 400th cycle is 789 mA h g-1.
Bibliographical notePublisher Copyright:
© 2015 American Chemical Society.
- Kirkendall effect
- lithium ion batteries
- reduced graphene oxide
- spray pyrolysis
ASJC Scopus subject areas
- Materials Science(all)