High-Performance Hybrid Asymmetric Supercapacitors with rGO/α-Fe۲O۳ and rGO/TiO۲ Nanocomposites

Supercapacitors, despite their importance in energy storage devices, exhibit lower energy density compared to batteries. Hybrid Asymmetric configuration, employing distinct cathode and anode materials, is a promising approach to address this challenge. This approach leads to an expanded potential window and, consequently, higher energy storage than conventional symmetric supercapacitors. Herein, we produced reduced graphene oxide /hematite (rGO/α-Fe۲O۳) and reduced graphene oxide /titanium dioxide (rGO/TiO۲) nanocomposites via hydrothermal technique. Field emission scanning electron microscope (FESEM) and X-ray diffractometry (XRD) were utilized to analyze morphology, structure, and phase of the nanocomposites. The XRD analysis confirmed the presence of the hematite and anatase in the rGO/α-Fe۲O۳ and rGO/TiO۲ nanocomposites, respectively. Additionally, in the XRD spectra of both nanocomposites, a broad peak corresponding to the (۰۰۲) crystalline planes of rGO was observed. The uniform distribution of spherical hematite and titanium dioxide nanoparticles on the rGO sheets was clearly observed in the FESEM images of the nanocomposites. The electrochemical behavior of the rGO/α-Fe۲O۳ and rGO/TiO۲ nanocomposites was investigated, and they exhibited specific capacities of ۱۳۰ and ۲۵۳ F/g, respectively, in ۱ M KOH electrolyte, at ۵ mVs-۱ scan rate. Then, a hybrid asymmetric supercapacitor was achieved using rGO/α-Fe۲O۳ as the anode and rGO/TiO۲ as the cathode. Electrochemical characterization in ۱ M KOH electrolyte revealed a ۱.۶ V operational potential window. Power density and energy density of ۱۰۶۶ W kg-۱ and ۹.۷ Wh kg-۱ were achieved at a current density of ۱ A/g, respectively.

کلیدواژه ها:

Hybrid Asymmetric supercapacitor ، Graphene oxide ، rGO/α-Fe۲O۳ nanocomposite ، rGO/TiO۲ nanocomposite.