High-performance lithium-ion battery and symmetric supercapacitors based on FeCo₂O₄ nanoflakes electrodes

A successive preparation of FeCo₂O₄ nanoflakes arrays on nickel foam substrates is achieved by a simple hydrothermal synthesis method. After 170 cycles, a high capacity of 905 mAh g^-1 at 200 mA g^-1 current density and very good rate capabilities are obtained for lithium-ion battery because of the 2D porous structures of the nanoflakes arrays. The distinctive structural features provide the battery with excellent electrochemical performance. The symmetric supercapacitor on nonaqueous electrolyte demonstrates high specific capacitance of 433 F g^-1 at 0.1 A g^-1 and 16.7 F g^-1 at high scan rate of 5 V s^-1 and excellent cyclic performance of 2500 cycles of charge-discharge cycling at 2 A g^-1 current density, revealing excellent long-term cyclability of the electrode even under rapid charge-discharge conditions.