Fabrication of 2D layered structure of rGO@Bi2O2CO3@NiCo-LDHs composite electrode for aqueous asymmetric supercapacitor

Two-dimensional layered structure of rGO@Bi 2 O 2 CO 3 @NiCo-LDHs as positive material of supercapacitor is fabricated using the simple hydrothermal reaction, freeze-drying technology, and heat treatment process. The corresponding electrode exhibits a maximum specific capacity of 1147 F/g at 0.5 A/g and 82.2% capacity retention after 1000 times charging and discharging at 10 A/g. Additionally, negative material of rGO film is also prepared, which has a higher specific capacity of 354 F/g than that of other carbon materials. To obtain a high performance of supercapacitor device, an asymmetric supercapacitor of rGO//rGO@Bi 2 O 2 CO 3 @NiCo-LDHs is assembled based on rGO@Bi 2 O 2 CO 3 @NiCo-LDHs, rGO film, and 2 M KOH electrolyte. The testing data show that the maximum specific capacitance and energy density of asymmetric supercapacitor are 85 F/g and 23.14 Wh/kg, respectively. Simultaneously, it also shows the good electrochemical stability, remaining 80% capacity after 3000 cycles. This means that rGO@Bi 2 O 2 CO 3 @NiCo-LDHs could be regarded as a promising electrode material for energy storage devices.