Flame spray pyrolysis for finding multicomponent nanomaterials with superior electrochemical properties in the CoO(x)-FeO(x) system for use in lithium-ion batteries

Abstract

High-temperature flame spray pyrolysis is employed for finding highly efficient nanomaterials for use in lithium-ion batteries. CoO(x)-FeO(x) nanopowders with various compositions are prepared by one-pot high-temperature flame spray pyrolysis. The Co and Fe components are uniformly distributed over the CoO(x)-FeO(x) composite powders, irrespective of the Co/Fe mole ratio. The Co-rich CoO(x)-FeO(x) composite powders with Co/Fe mole ratios of 3:1 and 2:1 have mixed crystal structures with CoFe2O4 and Co3O4 phases. However, Co-substituted magnetite composite powders prepared from spray solutions with Co and Fe components in mole ratios of 1:3, 1:2, and 1:1 have a single phase. Multicomponent CoO(x)-FeO(x) powders with a Co/Fe mole ratio of 2:1 and a mixed crystal structure with Co3O4 and CoFe2O4 phases show high initial capacities and good cycling performance. The stable reversible discharge capacities of the composite powders with a Co/Fe mole ratio of 2:1 decrease from 1165 to 820 mA h g(-1) as the current density is increased from 500 to 5000 mA g(-1); however, the discharge capacity again increases to 1310 mA h g(-1) as the current density is restored to 500 mA g(-1).

Keywords: batteries; energy storage; flame spray pyrolysis; gas-phase reaction; nanostructured materials.