Comparison of the electrochemical properties of yolk–shell and dense structured CoFe2O4 powders prepared by a spray pyrolysis process

Abstract

CoFe₂O₄ powders with yolk–shell and dense structures are both prepared by a simple spray pyrolysis process with the same preparation conditions. Sucrose dissolved in the spray solution changes the morphology from a dense structure into a yolk–shell structure. In the initial cycle, the yolk–shell CoFe₂O₄ powders exhibit discharge and charge capacities of 1158 and 902 mA h g⁻¹ respectively, at a current density of 1 A g⁻¹, while the dense CoFe₂O₄ powders exhibit capacities of 1071 and 677 mA h g⁻¹, respectively. After 200 cycles, the capacity retentions of the yolk–shell and dense powders after the first cycles are 83 and 47%. The yolk–shell powders exhibit not only good cycling stability but also good rate performance compared with the dense powders because of their structural advantages.