Structural and electrochemical properties of manganese oxide/rGO/PCL nanofiber for supercapacitor electrode material

In this work, manganese oxide (Mn₃O₄)/reduced graphene oxide (rGO)/polycaprolactone (PCL) electrospun nanofiber composite was synthesized for supercapacitor electrode applications. The SEM image showed nanofiber formation with an average diameter size ranging from 100 to 200 nm. The interlayer spacing (d) of rGO was 0.38 nm due to the oxygen functional group between the layers. The diffraction peak appeared at 19.4°, 31.4°, 32.5°, 36.1°, 44.5°, and 60.1° corresponding to (101), (112), (103), (211), (220), and (224) diffraction planes of Mn₃O₄/rGO/PCL nanofiber. The defect parameter (I_D/I_G) varied from 1.05 to 1.17 for rGO, PCL/rGO and Mn₃O₄/rGO/PCL nanocomposites, respectively. The estimated particle size (R_g) interdiffusion correlation length and surface fractal (D_s) from small angle X-ray Scattering (SAXS) of electrospun Mn₃O₄/rGO/PCL nanofiber is estimated at 8.5 nm, 2.3 nm, and 1.17, respectively. The maximum specific capacitance (C_sp) energy density and power density of Mn₃O₄/rGO/PCL nanofiber are 690 F/g, 17.46 Wh kg⁻¹, and 99.85 W kg⁻¹, respectively, at a current density of 1 A g⁻¹. In the analysis of corrosion, the I_corr and E_corr values for 1-M H₂SO₄ and 1-M KCl electrolytes are determined to be 5.781 A and 1.76 A as well as 0.3 and 0.4 V, respectively.