Preparation and electrochemical performance of porous hematite (α-Fe2O3) nanostructures as supercapacitor electrode material

Abstract

Porous α-Fe 2 O 3 nanostructures have been synthesized by sol-gel route. The effect of preparation temperature on the morphology, structure, and electrochemical stability upon cycling has been studied for supercapacitor application. The discharge capacitance of α-Fe 2 O 3 prepared at 300 °C is 193 F g −1 , when the electrodes are cycled in 0.5 M Na 2 SO 3 at a specific current of 1 A g −1 . The capacitance retention after 1,000 cycles is about 92 % of the initial capacitance at a current density of 2 A g −1 . The high discharge capacitance as well as stability of α-Fe 2 O 3 electrodes is attributed to large surface area and porosity of the material. There is a decrease in specific capacitance (SC) on increasing the preparation temperature. As iron oxides are inexpensive, the synthetic route adopted for α-Fe 2 O 3 in the present study is convenient and the SC is high with good cycling stability, the porous α-Fe 2 O 3 is a potential material for supercapacitors.

Investigation of hematite nanorod–nanoflake morphological transformation and the application of ultrathin nanoflakes for electrochemical devices

“…In fact, the areal capacitance of the NF electrode is much higher than most reported values of other hematite structures including porous particles (60 mF/cm 2 , @1 mA/cm 2 ) [23], nanotubes (33.9 mF/cm 2 , @4 mA/cm 2 ), [13] thin film (89 mF/cm 2 , @1 mA/cm 2 ), [39] nanotube arrays (107.8 mF/cm 2 , @1 mA/cm 2 ) [29] and is comparable to hematite nanotubes (~165 mF/cm 2 , @1 mA/cm 2 ). [16] Furthermore, NF electrode also showed good cycling stability with a capacitive retention rate of 87.2% after 5000 cycles ( Figure S10, Supporting Information).…”

“…Nanostructures with large surface area provides not only enhanced amount of surface active sites for chemical reactions, but also substantially reduce the diffusion length for charge carriers and counter ions. A number of hematite nanostructures including ordered hematite nanotube arrays, [15,16] porous nanofibers, [17], nanowires, [18,19] nanocubes, [9] nanorods, [3,4,20,21], nanocorals, [22] nanoparticles [23,24], and porous nanoflowers [25] have been synthesized and implemented as electrodes for (photo)electrochemical devices.…”

High-capacity carbon-coated titanium dioxide core–shell nanoparticles modified three dimensional anodes for improved energy output in microbial fuel cells

“…S3 show typical CVs of the capacitive electrodes in the potential range from À0.4 to 0.1 V vs. SCE at various scan rates. The nearly rectangular shapes of the CV curves suggest electric double-layer capacitance characteristics, which are distinguishable from normal pseudocapacitance [27]. There were significant differences in the currents in the CVs of the 3D electrodes coated with different materials, demonstrating the varied capacitive performance of the different electrodes.…”

Effect of carbon coating on the electrochemical properties of Bi2WO6 nanoparticles by PVP-assisted sonochemical method

“…The fabrication of nanomaterials with high porosity and enhanced surface area would also be an effective way. Also, there exists a positive synergistic effect between the graphene-based materials and metal oxides which forms an important strategy for the overcoming the difficulties of poor cycling performances [59][60][61].…”