Flame Spray Pyrolysis for Finding Multicomponent Nanomaterials with Superior Electrochemical Properties in the CoOx-FeOx 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. CoOx-FeOx nanopowders with various compositions are prepared by one-pot high-temperature flame spray pyrolysis. The Co and Fe components are uniformly distributed over the CoOx-FeOx composite powders, irrespective of the Co/Fe mole ratio. The Co-rich CoOx-FeOx 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 CoOx-FeOx 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 820mAhg(-1) as the current density is increased from 500 to 5000mAg(-1); however, the discharge capacity again increases to 1310mAhg(-1) as the current density is restored to 500mAg(-1).