Tailoring the Perovskite Structure to Acquire an Inorganic La₂NiCrO₆ Double Perovskite as an Efficient Energy Storage Application by Varying Molar Concentrations of Citric Acid

Owing to the high power density and long cycle stability, supercapacitors are promising energy storage devices instead of electrochemical batteries. In recent years, perovskite materials have received good attention in the research community for pseudocapacitive electrode material. Especially, these materials, having a high oxygen vacancy concentration, exhibit ultra-high capacitance due to oxygen-anion intercalations. In this study, La 2 NiCrO 6 (LNC) double perovskites are successfully synthesized using the sol–gel method followed by the solid–state reaction at different concentrations of citric acid. The interconnected spherical granular-structured LNC is an efficient supercapacitor electrode material because of its stress-free octahedron lattice and inherent oxygen vacancies. In a three-electrode system, LNC@Ni-foam reveals a specific capacity of 529 C g –1 (147 mA h g –1 ) at a current density of 1 A g –1 . To exhibit a real-time application, a device is fabricated with LNC@Ni-foam as a positive electrode and activated carbon (AC) AC@Ni-foam as a negative electrode. This asymmetric device can achieve the specific capacity of 227 C g –1 (63 mA h g –1 ) at a current density of 1 A g –1 . The fabricated device exhibits an energy density of 49.17 W h kg –1 at a power density of 779.79 W kg –1 . In addition, the as-fabricated device has a cycle stability of 97% even after 10,000 cycles at a current density of 10 A g –1 . These superior electrochemical performances promise the application of this LNC electrode in pseudocapacitors.