Rapid synthesis of Mn-doped NiFe2O4 nanosheet arrays for high-performance hybrid supercapacitors

Abstract

This research presents an innovative approach to the in-situ fabrication of Mn-doped NiFe2O4 (Mn-NiFe2O4) nanosheet arrays directly on nickel foam substrates. The formation of precursors on the nickel foam substrates is achieved through spontaneous corrosion, followed by a thermal treatment to form the Mn-NiFe2O4 nanosheet arrays. The material's structure and morphology were thoroughly examined, revealing that the addition of Mn transforms the nanoporous structure on the nickel foam into a nanosheet structure. The average thickness of the nanosheets is 30 nm, and their primary composition is Mn-doped NiFe2O4. The resulting highly porous structure of these nanosheets provides numerous active sites and effective electron and ion diffusion channels, thereby increasing charge density and mechanical stability. Electrochemical assays show that the areal-specific capacity of the synthesized electrode material reaches 4.34 C cm−2 (areal-specific capacitance is 8.68 F cm−2) at 1 mA cm−2. Notably, the constructed hybrid supercapacitor achieves a power density of 544 µW cm−2 at an energy density of 390 µWh cm−2. Furthermore, capacitance retention is 95.2% after 5000 charging cycles. Additionally, the assembled device delivers robust and sustained energy output for LED displays and electric toy cars. This method streamlines the production flow of electrode materials, reducing energy consumption while significantly enhancing the areal capacitance of supercapacitors. The assembled hybrid supercapacitor structure diagram and the assembled devices provide power sources for electric toy cars and LED displays.