NiCoO2 nanosheets interlayer network connected in reduced graphene oxide and MXene for high-performance asymmetric supercapacitors

The composite electrode materials (rGO/MXene@NiCoO 2 ) have been prepared by tightly wrapping of reduced graphene oxide (rGO) and MXene to NiCoO 2 nanosheets . The specific capacitance of rGO/MXene@NiCoO 2 -5wt% is 1614 F·g −1 at 0.5 A g −1 , maintains at 1257.5 F·g −1 when increasing the current density to 10 A·g −1 . And the capacitance retention is 77.29% even after 10,000 cycles. It is attributed to the special interlayer network structure of the rGO/MXene@NiCoO 2 composite, which promotes more ion intercalation/deintercalation and improves the structure stability. An asymmetric supercapacitor (ASC) is assembled using rGO/MXene@NiCoO 2 as the positive electrode and rGO/MXene as the negative electrode, respectively. The maximum energy density is 45.15 Wh·kg −1 and the power density is 394.52 W·kg −1 . After 10,000 cycles with current density at 5 A·g −1 , the capacity retention rate is 82.69%. These results demonstrate the potential application of rGO/MXene@NiCoO 2 composite networks as electrode materials for supercapacitors.