Fabrication of honeycomb-structured composite material of PrO, CoO, and graphene on nickel foam for high-stability supercapacitors

Hydrothermal synthesis and annealing process were used to create a honeycomb-structured composite electrode material on nickel foam substrate that contained praseodymium oxide (Pr 2 O 3 ), cobalt oxide (Co 3 O 4 ), and reduced graphene oxide (rGO) (named as Pr 2 O 3 /Co 3 O 4 /rGO/NF). The Pr 2 O 3 /Co 3 O 4 /rGO/NF (PCGN) composite electrode material was created without the need for a binder and can be employed right away to create a supercapacitor. This honeycomb composite is further grown by the mesh structure of Pr 2 O 3 and Co 3 O 4 , which has good electrical conductivity. This nanomorphology not only improves the specific surface area of the material but also facilitates the improvement of electron transfer efficiency. The synthesized electrode material has excellent electrochemical properties due to its special morphology and excellent conductivity, and its performance is better than that of praseodymium oxide and cobalt oxide alone, with a specific capacitance of 3316 F g −1 in the three-electrode system at a current density of 1 A g −1 . After forming a symmetrical supercapacitor device, the energy density is 74.8 W h kg −1 and the power density is 300 W kg −1 at 0.5 A g −1 . The capacitance retention is 82% even after 35 000 cycles at 2 A g −1 . The Pr 2 O 3 /Co 3 O 4 /rGO/NF electrode has been prepared by hydrothermal method and annealing process, with high specific capacitance and excellent cycle stability.