In Situ Growth of FeCo-Selenide on Ni Foam as High-Performance Electrode for Electrochemical Energy Storage Devices

A solid-state energy storage device has been fabricated using FeCo-selenide nanosheet arrays as positive electrode and Fe 2 O 3 nanorod as negative electrode. As an electrode material, the ternary FeCo-selenide nanosheet arrays supported by Ni foam show a highest specific capacitance of 978 F/g (specific capacity of 163 $$ mAh/g) at 1 A/g and a superior cycle behavior of 81.2% are obtained after 5000 cycles at current density of 4 A/g. The asymmetric supercapacitor achieves the maximum energy density of 34.6 $$ W $$ h/kg at the power density of 759.6 $$ W/kg. Furthermore, the superior cycling stability with 83% retention of initial capacitance after 5000 cycles further verify the practical applications of FeCo-selenide//Fe 2 O 3 asymmetric supercapacitor. Meanwhile, the LED bulb and the light board of “CUMT” are lighted by connecting several capacitors to form a series circuit.