Porous Fe2O3 Nanorods on Hierarchical Porous Biomass Carbon as Advanced Anode for High-Energy-Density Asymmetric Supercapacitors

Abstract

In this study, a novel negative electrode material was prepared by aligning α-Fe2O3 nanorods on a hierarchical porous carbon (HPC) skeleton. The skeleton was derived from wheat flour by a facile hydrothermal route to enhance conductivity, improve surface properties, and achieve substantially good electrochemical performances. The α-Fe2O3/HPC electrode exhibits enhanced specific capacitance of 706 F g−1, which is twice higher than that of α-Fe2O3. The advanced α-Fe2O3/HPC//PANI/HPC asymmetrical supercapacitor was built with an expanded voltage of 2.0 V in 1 M Li2SO4, possessing a specific capacitance of 212 F g−1 at 1 A g−1 and a maximum energy density of 117 Wh kg−1 at 1.0 kW kg−1, along with an excellent stability of 5.8% decay in capacitance after 5,000 cycles. This study affords a simple process to develop asymmetric supercapacitors, which exhibit high electrochemical performances and are applicable in next-generation energy storage devices, based on α-Fe2O3 hybrid materials.

WITHDRAWN: Nitrogen-Doped Carbon Boosting Fe2O3 Anode Performance for Long-Life Supercapacitors

“…Nevertheless, there are still some problems in the process of constant current charge and discharge, such as poor conductivity and large volume change, resulting in serious electrode pulverization, particle cracking and capacity loss [22,23]. In order to overcome these problems, various strategies have been developed, such as surface coating with conductive materials and constructing nanostructured materials with different morphologies [24,25,26,27,28]. Among these methods, the design of Fe 2 O 3 /carbon composites with nano structure shows great application prospects in commercial applications because of their economical preparation methods [29].…”

Metal-Supported Biochar Catalysts for Sustainable Biorefinery, Electrocatalysis, and Energy Storage Applications: A Review

“…Apart from Ni-and Mn-post-activated biochar supercapacitors, biomass-derived carbons decorated with Fe-containing species attracted significant attention. Recently, two works reported the fabrication of Fe 2 O 3 /biocarbon nanocomposites for supercapacitor applications from wheat, one of them by carbonizing wheat straw [125] and the other, wheat flour [126]. The former [125] proposed the formation of an ultrathin Fe 2 O 3 film on the straw-derived carbon, generating a synergistic effect between both components that, along with a hierarchical porosity, led to a remarkable capacitance of 987.9 F g -1 (at 1 A g -1 of current density) and important cycling stability.…”

“…Furthermore, the asymmetric supercapacitor assembled with this nanocomposite as anode material achieved large energy and power densities, 96.7 Wh kg -1 and 20.65 kW kg -1 , respectively. The latter article [126], published in 2020, reported the hydrothermal synthesis from Fe(NO 3 ) 3 •9H 2 O and Na 2 SO 4 of porous Fe 2 O 3 nanorods supported on wheat flour-derived carbon. This material showed an interesting electrochemical behavior as electrode, such as a C sp value of 706 F g −1 , and assembled in a hybrid supercapacitor device, a specific capacitance of 212 F g −1 (at 1 A g −1 ), maximum energy density of 117 Wh kg −1 (at 1.0 kW kg −1 ), and only 5.8% capacitance loss over 5000 charge-discharge cycles.…”

Green Preparation of Fe2O3Doped Gum Acacia Derived Porous Carbon/Graphene Ternary Nanocomposite as a Supercapacitor Electrode

“…The ternary composite shows good specific capacitance values of 433, 97, 88, 84, 23, 14, and 12 F/g at current densities of 6, 7, 9, 10, 25, 50, and 100 A/g, respectively. The synergistic behavior attained by the ternary composite is composed of high pseudocapacitance of Fe 2 O 3 , fast electrolyte diffusion on porous carbon, and the highly conducting high surface area graphene sheets with good EDLC [60]. The galvanostatic CD curves of Fe 2 O 3 -PC/graphene-modified electrodes at different current densities are shown in Figure 7(c).…”