Electrode Material For Asymmetric Supercapacitors Research Articles

β-Ni(OH)2 nanoparticles@activated sugarcane bagasse carbon nanocomposites as an advanced hybrid electrode material for asymmetric supercapacitors

β-Ni(OH)2 nanoparticles (NPs)@activated sugarcane bagasse carbon (ASBC) nanocomposites (N@ASBC NCps) with different Ni loadings were synthesized using a hydrothermal process. The products were characterized using techniques such as X-ray diffraction (XRD), field emission scanning and transmission electron microscopy (FE-SEM and TEM), Raman spectroscopy, and Fourier transform infrared spectroscopy (FT-IR). Electrochemical performance of the products was studied. Interestingly, the maximum specific capacitance of 1213.32 F/g at 1 A/g could be achieved in a 3N@ASBC NCps positive electrode. Concurrently, the ASBC negative electrode revealed a high specific capacitance of 233.34 F/g at 1 A/g. Additionally, the fabricated asymmetric supercapacitor (ASC), ASC-ASBC//3N@ASBC NCps, had a specific capacitance (Csc) of 34.03 F/g at 1 A/g with a specific energy density (Ed) and specific power density (Pd) of 9.93 Wh/kg and 181.26 W/kg, respectively. Moreover, the device could maintain 69.47% of its capacity after a 5000-cycle test.

Fabrication of porous Ni–Co LDH@rGO nanocomposites as efficient electrode materials for asymmetric supercapacitor

Fabrication of porous Ni–Co LDH@rGO nanocomposites as efficient electrode materials for asymmetric supercapacitor

Synergistic effects of Ag nanoparticles in the rGO and Co3O4 based electrode materials for asymmetric supercapacitors

A systematic investigation of the composite electrode materials is vital in fabricating supercapacitors with high specific capacitance and good stability. The present work systematically studies the synergistic effects of Ag nanoparticles (AgNPs) on the electrochemical behaviour of rGO-based supercapacitor anode and Co3O4/rGO composite cathode. The Co3O4/(Ag/rGO) composite has been fabricated by hydrothermally growing Co3O4 nanoparticles over the previously prepared Ag/rGO support in the 70:30 ratio. The electrochemical performance of fabricated electrodes was evaluated by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) in 1 M KOH electrolyte. The Ag/rGO electrode having 15 - 20 % of AgNPs displays a specific capacitance of 553.6 F/g by CV (@10 mV/s) and 449.4 F/g by GCD (@0.35 A/g), which is 2.9 – 3.1 times higher than pristine rGO, when scanned in the range of – 1.0 V - 0.0 V (Vs. Ag/AgCl). The Co3O4/(Ag-20/rGO) composite electrode (in the ratio 70:30) possesses 244.9 F/g of specific capacitance (by GCD @3.8 A/g in the range of – 0.2 V - 0.5 V (Vs. Ag/AgCl)), which is 3.2 and 2.0 times higher than Co3O4 and Co3O4/rGO respectively. The Co3O4, Co3O4/rGO and Co3O4/(Ag/rGO) samples retained 67 % (at 3.8 A/g), 91 % (@1.4 A/g), and 82 % (@1.4 A/g) of specific capacitance after 2000 cycles. The asymmetric supercapacitor device in rGO||Co3O4/Ag/rGO configuration shows an initial specific capacitance of 438.0 F/g, energy and power densities of 38.9 Whkg‒1 and 640 Wkg‒1, respectively, at 2 A/g current density. The demonstrated boost in performance arises due to the presence of Ag nanoparticles leading to enhanced conductivity, catalyzing the pseudocapacitive reactions and preventing the graphene layers from aggregation by acting as spacers, spacers, thus making Ag/rGO and Co3O4/Ag/rGO as potential electrode materials for asymmetric supercapacitors.

Facile synthesis of Mn3O4 nanoparticles towards high performance asymmetric supercapacitors

In the present study, Mn3O4 nanostructured particles were prepared using a one-step hydrothermal method with varying different surfactants such as CTAB, PVA and EDTA, referred to as M-CTAB, M-PVA and M-EDTA, respectively. The structural properties were systematically studied using XRD, FTIR, SEM, TEM and XPS analysis. The electrochemical performance was assessed by CV, GCD and EIS measurements. The specific capacitance of the Mn3O4 electrodes was calculated using GCD at different current densities and CV at different scan rates. The specific capacitance values of the Mn3O4, M-CTAB, M-PVA and M-EDTA were 147.5, 156.5, 157.1 and 202.7 F g−1 at 5 mV s−1, 185.6, 209.5, 211.8 and 288.8 F g−1 at 0.5 A g−1. A superior capacitance retention of 99.4 % was observed for M-EDTA electrode even after 5000 continuous charge discharge cycles. An asymmetric supercapacitor (ASC) device made of M-EDTA//AC has a high energy and power densities of 36.9 Wh kg−1, 1043 W kg−1, respectively. Two ASC devices connected in series illuminated a red LED for 90 s. Thus, the M-EDTA can be regarded as promising electrode material for asymmetric supercapacitors.

Bimetallic Nanoparticles Embedded in P,N,Br‐Codoped Carbon Matrices Derived from Heterometallic‐Organophosphine Frameworks as Electrode Materials for Asymmetric Supercapacitors

AbstractAn unprecedented method has been developed to obtain heterometallic‐organophosphine frameworks (HMOPFs) through a solvent‐free, three‐component mechanochemical process. In a ball mill, mixing copper (I) bromide with zinc (II), nickel (II) or copper (II) acetates, in the presence of (PTA‐CH2‐C6H4‐p‐COOH) Br (PTA is 1,3,5‐triaza‐7‐phosphaadamantane) as an organic linker, has produced the corresponding HMOPFs based on Cu+‐Zn2+, Cu+‐Ni2+ and Cu+‐Cu2+, respectively. The pyrolysis of HMOPFs resulted in bimetallic nanoparticles of transition metal phosphide and phosphate embedded in multi‐P,N,Br‐codoped carbon matrices (Cu−M@C). Due to the utilization of an aminophosphine organic linker, this HMOPFs‐derived approach typifies an eco‐friendly synthesis of carbon confined transition metal phosphides or phosphates. It avoids the common conventional methods that involves phosphorylation using large amounts of additional P sources, which leads to an intensive release of the flammable and poisonous phosphine gas. Also, the presence of Br at the organic linker eliminates the need for using bromine vapours to obtain halogen‐doped carbon matrices. The Cu−M@C nanocomposites were tested as negative electrode materials for asymmetric supercapacitors. Electrochemical tests included cyclic voltammetry and galvanostatic charge‐discharge experiments, which revealed the Cu−Zn@C electrode with a higher potential window as compared to Cu−Ni@C and Cu−Cu@C electrodes, achieving a rate performance of 60 % and high coulombic efficiency.

Synergistic coupling of MnS/Ni3S2 and Co(OH)2 nanosheets as binder-free electrode materials for asymmetric supercapacitors with enhanced performance

The fabrication of electrode materials with a high specific capacitance is essential for the development of enhanced performance supercapacitors. A novel binder-free electrode material, composed of MnS/Ni3S2 and Co(OH)2, was synthesized on nickel foam by hydrothermal, sulfuration, and electrodeposition techniques. The MnS/Ni3S2 exhibited a unique flower-like structure, resulting in a high specific capacitance of 1780 F g−1 at 1 A/g. By optimizing the synthesis conditions through several characterization and electrochemical tests, the MnS/Ni3S2@Co(OH)2 composite was obtained, which displayed an ultrahigh specific capacitance of 2495 F g−1 at 1 A/g and a capacitance retention rate of 86.1% after 5000 cycles at 10 A/g in three-electrode system. The synergistic coupling of MnS/Ni3S2 and Co(OH)2, along with the conductive nickel foam substrate, donated towards the excellent electrochemical performance. Furthermore, the MnS/Ni3S2@Co(OH)2//AC asymmetric supercapacitor (ASC) device was constructed with MnS/Ni3S2@Co(OH)2 as positive electrode, activated carbon (AC) as negative electrode and 1 M KOH solution as electrolyte, demonstrated a high energy density of 68.6 Wh kg−1 at 750 W kg−1 and excellent cycle stability with 91.2% capacitance retention after 10,000 cycles at 15 A/g. The outstanding electrochemical properties observed in both the pre-electrodeposition and post-electrodeposition samples indicate the effectiveness of reasonable design and construction of composite as a pathway for producing electrode materials with exceptional performance.

Hydrothermally synthesized cobalt oxide embedded polymer nanocomposites as efficient electrode material for asymmetric supercapacitors

Hydrothermally synthesized cobalt oxide embedded polymer nanocomposites as efficient electrode material for asymmetric supercapacitors

A self-sacrificing template strategy: In-situ construction of bimetallic MOF-derived self-supported CuCoSe nanosheet arrays for high-performance supercapacitors

Transition metal selenides (TMSs) are viewed as a prospective high-capacity electrode material for asymmetric supercapacitors (ASCs). However, the inability to expose sufficient active sites due to the limitation of the area involved in the electrochemical reaction severely limits their inherent supercapacitive properties. Herein, a self-sacrificing template strategy is developed to prepare self-supported CuCoSe (CuCoSe@rGO-NF) nanosheet arrays by in situ construction of copper-cobalt bimetallic organic framework (CuCo-MOF) on rGO-modified nickel foam (rGO-NF) and rational design of Se2- exchange process. Nanosheet arrays with high specific surface area are considered to be ideal platforms for accelerating electrolyte penetration and exposing rich electrochemical active sites. As a result, the CuCoSe@rGO-NF electrode delivers a high specific capacitance of 1521.6 F/g at 1 A/g, good rate performance and an excellent capacitance retention of 99.5% after 6000 cycles. The assembled ASC device has a high energy density of 19.8 Wh kg−1 at 750 W kg−1 and an ideal capacitance retention of 86.2% after 6000 cycles. This proposed strategy offers a viable strategy for designing and constructing electrode materials with superior energy storage performance.

Lewis Acid Catalyzed Amide Bond Formation in Covalent Graphene-MOF Hybrids.

Covalent hybrids of graphene and metal-organic frameworks (MOFs) hold immense potential in various technologies, particularly catalysis and energy applications, due to the advantageous combination of conductivity and porosity. The formation of an amide bond between carboxylate-functionalized graphene acid (GA) and amine-functionalized UiO-66-NH2 MOF (Zr6O4(OH)4(NH2-bdc)6, with NH2-bdc2- = 2-amino-1,4-benzenedicarboxylate and UiO = Universitetet i Oslo) is a highly efficient strategy for creating such covalent hybrids. Previous experimental studies have demonstrated exceptional properties of these conductive networks, including significant surface area and functionalized hierarchical pores, showing promise as a chemiresistive CO2 sensor and electrode materials for asymmetric supercapacitors. However, the molecular-level origin of the covalent linkages between pristine MOF and GA layers remains unclear. In this study, density functional theory (DFT) calculations were conducted to elucidate the mechanism of amide bond formation between GA and UiO-66-NH2. The theoretical calculations emphasize the crucial role of zirconium within UiO-66, which acts as a catalyst in the reaction cycle. Both commonly observed hexa-coordinated and less common hepta-coordinated zirconium complexes are considered as intermediates. By gaining detailed insights into the binding interactions between graphene derivatives and MOFs, strategies for tailored syntheses of such nanocomposite materials can be developed.

NiCoP/Co9S8 nanoflowers as advanced electrode material for asymmetric supercapacitors

This work presents the synthesis of NiCoP using the Kirkendall effect and the preparation of a three-dimensional (3D) nanoflower-like structure of NiCoP/Co9S8 through sulfur-induced dissociation. The optimized electrode sample exhibited a capacity of 1252 μAh cm−2 (31.3 mAh g−1) at 1 mA cm−2 and 898 μAh cm−2 (22.5 mAh g−1) at 30 mA cm−2. The assembled NiCoP/Co9S8 electrode/active carbon (AC)-based asymmetric supercapacitor (ASC) demonstrated a capacity retention rate of 87 % after 5000 cycles at 20 mA cm−2 current density. Furthermore, the optimized NiCoP/Co9S8 composite showed a power density of 480.1 W kg−1 at an energy density of 115.1 Wh kg−1 and a power density of 4800.1 Wh kg−1 at an energy density of 66.4 W kg−1. These findings highlight the potential of the 3D NiCoP/Co9S8 nanoflower-like structure for application in asymmetric supercapacitors.

2D g-C3N4 decorated with 1D Bi2S3 nanocomposite as a high performance electrode material for asymmetric supercapacitors

Energy accumulation and storage is one of the most vital areas and necessities in today's world. The supercapacitor is seen as one of the most promising energy storage devices for upcoming generations. In this work, two dimensional (2D) g-C3N4 nanosheets decorated with one dimensional (1D) Bi2S3 nanorods by using rapid and simple hydrothermal method. The structure, functional groups, morphology and elemental analyses of synthesized materials were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDAX). In electrochemical study, pure Bi2S3 nanorods, g-C3N4 nanosheets, and Bi2S3/g-C3N4 composite electrode material were tested. In compared to pure samples, the Bi2S3/g-C3N4 composite demonstrated high specific capacitance of 631 Fg-1 at a current density of 1 Ag-1, as well as outstanding cyclic stability of 94% retained over 5000 cycles at a maximum current density in aqueous Na2SO4 electrolyte. The Bi2S3/g-C3N4 composite electrode exhibits superior electrochemical performance owing to the synergetic effect of Bi2S3 nanorods and g-C3N4 nanosheets. Also, the Bi2S3/g-C3N4 composite has been suggested as an excellent electrode material for supercapacitor applications. The fabricated Asymmetric supercapacitor device (ASC) has high specific capacitance of 80 F g−1 with 89% capacitance retention after 5000 cycle at current density of 10 A g−1. The ASC device achieved maximum energy density of 44.4 Wh kg−1 at 999 W kg−1 in operating potential range 0–2 V. Also ASC device fabricated for practical application and tested by charging 30 S and attained a self-discharging time of 3 min.

Nanoflower-like Cu2CoSnS4 grown on nickel foam as binder-free electrode material for asymmetric supercapacitors with high rate and capacitance

The self-supporting binder-free electrode material with a special porous structure and abundant electrochemical active sites is viewed as the ideal electrode material for supercapacitors. In this work, nanoflower-like Cu2CoSnS4 was first constructed on nickel foam (NF) substrate (CCTS/NF) by a one-step solvothermal method. The nanoflower-like shape increases the channels for ion transport and presents a massive quantity of active sites, which is crucial to improving electrochemical performance. What’s more, the significant synergistic effect between the ternary transition metal ions enhances the electrochemical performance as well. As a result, the CCTS/NF-3 performs a standout specific capacitance of 1690 mF cm-2 at 2 mA cm-2, a perfect rate performance of 79.6% and a superb cycle consistency of 99.6% after 5000 cycles. The assembled asymmetric supercapacitor (ASC) performs a high potential window of 0–1.4 V, a superb energy density of 0.0065 mWh cm-2 at 0.14 mW cm-2 and magnificent capacitance remains (95.6% after 5000 cycles). The electrode material has low acquisition cost and terrific electrochemical performance, and has broad utility possibilities in the supercapacitor market.

Achieving Ultrahigh Energy-Density Aqueous Supercapacitors via a Novel Acidic Radical Adsorption Capacity-Activation Mechanism in Ni(SeO3 )/Metal Sulfide Heterostructure.

Transitional metal chalcogenide (TMC) is considered as one promising high-capacity electrode material for asymmetric supercapacitors. More evidence indicates that TMCs have the same charge storage mechanism as hydroxides, but the reason why TMC electrode materials always provide higher capacity is rare to insight. In this work, a Nix Coy Mnz S/Ni(SeO3 ) (NCMS/NSeO) heterostructure is prepared on Ni-plated carbon cloth, validating that both NCMS and NSeO can be transformed into hydroxides in electrochemical process as accompanying with the formation of SeO3 2- and SOx 2- in confined spaces of NCMS/NSeO/Ni sandwich structure. Based on density functional theory calculation and experimental results, a novel space-confined acidic radical adsorption capacity-activation mechanism is proposed for the first time, which can nicely explain the capacity enhancement of NCMS/NSeO electrode materials. Thanks to the unique capacity enhancement mechanism and stable NCMS/NSeO/Ni sandwich structure, the optimized electrodes exhibit a high capacity of 536 mAh g-1 at 1 A g-1 and the impressive rate capability of 140.5mAhg-1 at the amazing current density of 200 A g-1 . The assembled asymmetric supercapacitor achieves an ultrahigh energy density of 141 Wh Kg-1 and an impressive high-rate capability and cyclability combination with 124% capacitance retention after 10 000 cycles at a large current density of 50 A g-1 .

A SnO2/MXene hybrid nanocomposite as a negative electrode material for asymmetric supercapacitors

A tin oxide/MXene hybrid (SnO2/Ti3C2Tx-80) was synthesized by a single step hydrothermal route and used as a negative electrode towards the fabrication of an asymmetric supercapacitor.

Iron-selenide-based titanium dioxide nanocomposites as a novel electrode material for asymmetric supercapacitors operating at 2.3 V.

This study portrays a facile wet-chemical synthesis of FeSe2/TiO2 nanocomposites for the first time for advanced asymmetric supercapacitor (SC) energy storage applications. Two different composites were prepared with varying ratios of TiO2 (90 and 60%, symbolized as KT-1 and KT-2) and their electrochemical properties were investigated to obtain an optimized performance. The electrochemical properties showed excellent energy storage performance owing to faradaic redox reactions from Fe2+/Fe3+ while TiO2 due to Ti3+/Ti4+ with high reversibility. Three-electrode designs in aqueous solutions showed a superlative capacitive performance, with KT-2 performing better (high capacitance and fastest charge kinetics). The superior capacitive performance drew our attention to further employing the KT-2 as a positive electrode to fabricate an asymmetric faradaic SC (KT-2//AC), exceeding exceptional energy storage performance after applying a wider voltage of 2.3 V in an aqueous solution. The constructed KT-2/AC faradaic SCs significantly improved electrochemical parameters such as capacitance of 95 F g-1, specific energy (69.79 Wh kg-1), and specific power delivery of 11529 W kg-1. Additionally, extremely outstanding durability was maintained after long-term cycling and rate performance. These fascinating findings manifest the promising feature of iron-based selenide nanocomposites, which can be effective electrode materials for next-generation high-performance SCs.

Facile route to high-mass-loading amorphous NiCo-MOFs as high-performance electrode materials for asymmetric supercapacitors

In the current work, synthesis of an amorphous NiCo-MOF with an ultra-high mass loading (10.3 mg cm−2) and an ultra-thick plate structure was achieved via a one-step solvothermal method.

ВЛИЯНИЕ РЕЖИМОВ СИНТЕЗА НА ЭЛЕКТРОХИМИЧЕСКИЕ ХАРАКТЕРИСТИКИ КОМПОЗИТОВ НА ОСНОВЕ МНОГОСТЕННЫХ УГЛЕРОДНЫХ НАНОТРУБОК И ОКСИДА МАРГАНЦА, ЛЕГИРОВАННОГО ОКСИДОМ СЕРЕБРА

In this work, promising electrode materials for asymmetric supercapacitors based on multiwalled carbon nanotubes and manganese oxide doped with silver oxide were obtained and studied. To form the composites, the method of exposure of carbon material in an aqueous solution of potassium permanganate with the addition of silver nitrate in various quantities was used. It has been established that an increase in the amount of silver nitrate during the formation of the composite leads to an increase in the mass loading of the composite with both silver oxide and manganese oxide, which provides higher electrochemical characteristics of the material. The maximum specific capacity of the composite with a high content of manganese and silver was about 146 and 65 F/g at discharge current densities of 0.1 and 1.0 A/g, respectively. The high capacitive characteristics of the composite are ensured by a combination of the electrochemical activity of manganese oxide and the low electrical resistance of silver oxide.

Hierarchical core-shell NiCoSe2@nickel cobalt layered double hydroxide nanocomposite as high-performance electrode materials for asymmetric supercapacitors

As an efficient energy storage device, supercapacitors have exhibited excellent charge storage capacity and stable cycling performance. However, the lower energy density makes it difficult to meet the performance requirements in practical applications. Here, a core-shell structure of NiCoSe2@NiCo-LDH was synthesized on carbon cloth by a two-step method. The NiCoSe2@NiCo-LDH composite as electrode of supercapacitor exhibited a specific capacitance of 2609.1 mF cm−2 (1242.4F g−1) in three-electrode system, which was far higher than that of the NiCoSe2 electrode material, maintaining 85 % of the original capacity after 2000 cycles. The NiCoSe2@NiCo-LDH and activated carbon materials were further assembled to an asymmetric supercapacitor to verify their performance of real applications. The device exhibited a specific capacity of 912.5 mF cm−2 at a current density of 2 mA cm−2 and maintained 96.19 % of its original capacity after 2000 cycles, demonstrating its application potential.

Superior capacitive performance of spherical MnV2O6·2H2O-graphene nanosheet hybrid as electrode material for asymmetric supercapacitor

The evolution of advanced supercapacitors depends highly on the design and synthesis of electrodes with rational morphology and structure. In this paper, a facile methanol-assisted solvothermal method is reported for the synthesis of spherical hydrated manganese vanadate (MnV2O6·2H2O)-reduced graphene oxide (rGO) nanosheets hybrid. In particular, the utilization of methanol can not only change the isotropy growth of MnV2O6 but also suppresses the phase-transformation process (from orthorhombic to monoclinic) by preventing the deintercalation of crystal water. Remarkably, the MnV2O6·2H2O exhibits a superior specific capacity of 1678.5 F g−1 which is nearly four times more than that of MnV2O6 (410.2 F g−1) at 2 A g−1. After integrating with graphene, MnV2O6·2H2O spheres are uniformly encapsulated by graphene sheets with a size reduction from 1 μm to 200 nm. And a “GO-assisted Ostwald ripen-splitting” mechanism is proposed to explain the formation of MnV2O6·2H2O-rGO. Consequently, the MnV2O6·2H2O-rGO hybrid exhibits significantly improved conductivity, enhanced specific capacity (1976.3 F g−1 at 2 A g−1) and good rate capability (1422.5 F g−1 at 10 A g−1 and 1155.5 F g−1 at 20 A g−1) as well as excellent cycling stability (94.2% capacitance retention after 10,000 cycles). Moreover, the assembled asymmetric supercapacitor using MnV2O6·2H2O-rGO (the positive electrode) and activated carbon (the negative electrode) shows a superior energy density of 51.5 Wh⋅kg−1 at the power density of 849.2 W kg−1.

2D ultrathin basic cobalt carbonate nanosheets grown on nickel foam as high-performance electrode materials for asymmetric supercapacitors

• 2D ultrathin basic cobalt carbonate nanosheets were successfully fabricated; • The obtained product exhibited an ultrahigh areal capacitance of 4.7 F/cm 2 ; • The corresponding asymmetric supercapacitor exhibited a high energy density; • The obtained sample could be a promising candidate for supercapacitors. In this work, high density 2D ultrathin basic cobalt carbonate nanosheets supported by Ni foam(NF) had been successfully fabricated via a one-step hydrothermal route. Owing to the presence of ultrathin 2D structure and opening channels among nanosheets were beneficial to increase the electron transmission rate and the ion diffusion rate, the resulted basic cobalt carbonate based electrode expressed an ultrahigh areal capacitance of 4.7 F/cm 2 at 6 mA/cm 2 and a good capacitance retention of 91 % even after 5000 cycles, which was superior than those of previously reported basic cobalt carbonate based materials. Besides, the corresponding asymmetric supercapacitor was assembled and exhibited a high energy density of 0.68 mWh/cm 2 at a power density of 4.23 mW/cm 2 . It can be anticipated that the obtained 2D ultrathin basic cobalt carbonate nanosheets could be a promising candidate for high-performance supercapacitors.