One-step route synthesis of active carbon@La2NiO4/NiO hybrid coatings as supercapacitor electrode materials: Significant improvements in electrochemical performance

•Active carbon was modified by inorganic conductive composite materials La2NiO4/NiO.•The composite has a highly nanoporous structure and high specific surface area.•The composite possesses a low resistance and a high specific capacitance.

Active carbon@La2NiO4/NiO hybrid coatings are synthesized using different molar ratios of La/Ni to improve the electrochemical performance of active carbon materials. The morphology and microstructure of the composites are investigated via scanning electron microscopy (SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). Cyclic voltammetry (CV), galvanostatic charge/discharge test (GCD), and electrochemical impedance spectroscopy (EIS) are performed to characterize electrochemical performance. At a molar ratio of La/Ni 1:2, the electrochemical electrode shows that the resistance of the composite is 2.97 Ω, which is half of that in pure active carbon. The highest energy density of 70.37 W h kg−1 is obtained at a current density of 1 A g−1, whereas the highest power density of 32.4 kW kg−1 is achieved at a current density of 10 A g−1. The CV results present a high specific capacitance of 710.48 F g−1 at a scan rate of 1 mV s−1 in 7 M KOH aqueous solution.