High capacitive rare-earth co-doped transition metal/graphene oxide composites as effective electrode material for supercapacitors

Abstract

In recent times, there has been a surge of attention towards advanced high-performance materials for storing energy, specifically in supercapacitors. One encouraging method involves utilizing nanocomposites based on transition metal oxides/graphene which have demonstrated significant potential for improving capacitance. The electrochemical properties of titanium oxide doped graphene in current research have been improved through the incorporation of rare earth metals. The hydrothermal technique was chosen for the fabrication of nanocomposites as electrode materials. X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) approaches were employed for the characterization of nanocomposites. Ternary and quaternary nanocomposites with 2 wt% rare earth elements doped with titanium oxide and graphene were synthesized with various ratios of lanthanum and cerium as dopants. In 2 wt% La:Ce-TiO₂/rGO, lanthanum, and cerium were doped in 1:1, 1:3, and 1:5 ratios. 2 wt% La:Ce(1:5)-TiO₂/rGO among co-doped composites exhibits better capacitive performance as determined through cyclic voltammetry and galvanostatic charge–discharge. Among all the nanocomposites 422 F/g was the maximum depicted by 2 wt% La:Ce(1:5)-TiO₂/rGO at a scan rate of 10 mV/s (potential window from −0.4 to +0.6 V) and 1895 F/g at 1 mV/s (potential window −0.6 to +0.6 V). specific capacitance was also determined via GCD, and a maximum capacitance of 486 F/g is depicted by 2 wt% La:Ce(1:5)-TiO₂/rGO. The same composites have also served as promising electrode materials in terms of columbic efficiency, power, and energy density.