Materials For Supercapacitors Research Articles

Effect of Functionalized Carbon Nanotubes and Graphene Oxide Nanoribbons on the Supercapacitive Behavior of Zr-Based Metal-Organic Frameworks in Acid Media

Metal-organic frameworks (MOFs) as a kind of crystalline porous materials have attracted much attention due to their high surface area and high electrochemical performance as electrode materials in supercapacitors 1. Recently, there has been a lot of interest in functionalized multiwalled carbon nanotubes (F-MWCNTs) based materials and especially graphene oxide nanoribbons (GONRs), which have unusual characteristics of ultrathin two-dimensional structures and, as promising materials for supercapacitors and other electrochemical energy storage devices. The F-MWCNTs and GONRs' high electrical conductivity, highly changeable surface area, strong chemical stability, excellent mechanical behavior, and capacity to modify attributes for the desired application are behind the reasons for choosing to make a composite of these materials with Zr-MOF 2.In this work, Zr-MOF was synthesized using the solvothermal method 3, MWCNTs were functionalized using acid washing (3 M H2SO4: 1 M HNO3), and GONRs were fabricated using the oxidative unzipping method 4. The Zr-MOF/F-MWCNTs and Zr-MOF/GONRs composites were prepared through physical mixing. The physical and chemical structures of the synthesized Zr-MOF, F-MWCNTs, and GONRs were evaluated using XRD, SEM, TEM, FT-IR, Raman spectroscopy, and XPS. The supercapactive behavior of the prepared composites was evaluated in comparison to their components (Zr-MOF, F-MWCNTs, and GONRs) in 1M H2SO4 utilizing various evaluation systems (three and two-electrode systems). Zr-MOFs showed a high specific capacitance (248 F/g at 1 A/g), making it a promising supercapacitor electrode material. That performance is dramatically improved by the addition of the nanocarbon materials (F-MWCNTs and GONRs). Zr-MOF-GONRs showed the highest specific capacitance (448 F/g at 1 A/g), with a large potential window (1.7 V) in the three-electrode system extended to (2V) in the two-electrode system, and good stability over 10,000 cycles at a high current density of 10 A/g. Reference: (1) Tan, Y.; Zhang, W.; Gao, Y.; Wu, J.; Tang, B. Facile Synthesis and Supercapacitive Properties of Zr-Metal Organic Frameworks (UiO-66). RSC Adv. 2015, 5 (23), 17601–17605. https://doi.org/10.1039/c4ra11896k.(2) Shrivastav, V.; Sundriyal, S.; Tiwari, U. K.; Kim, K. H.; Deep, A. Metal-Organic Framework Derived Zirconium Oxide/Carbon Composite as an Improved Supercapacitor Electrode. Energy 2021, 235, 121351. https://doi.org/10.1016/j.energy.2021.121351.(3) Abdelhamid, H. N. UiO-66 as a Catalyst for Hydrogen Production: Via the Hydrolysis of Sodium Borohydride. Dalton Trans. 2020, 49 (31), 10851–10857. https://doi.org/10.1039/d0dt01688h.(4) Kosynkin, D. V.; Higginbotham, A. L.; Sinitskii, A.; Lomeda, J. R.; Dimiev, A.; Price, B. K.; Tour, J. M. Longitudinal Unzipping of Carbon Nanotubes to Form Graphene Nanoribbons. Nature 2009, 458 (7240), 872–876. https://doi.org/10.1038/nature07872.

Advancing Electrochemical Energy Storage: The Synergistic Impact of Sulfur Nano-Confinement in Hierarchically Porous Jute-Derived Activated Carbon for Enhanced Supercapacitor Performance

The availability of energy is a cornerstone for the modernization, automation, and economic growth of nations. With the rapid depletion of fossil fuels and rising environmental concerns, such as CO2 emissions leading to global warming, there has been an intensified search for alternative, renewable energy sources like solar and wind power. However, their intermittent nature necessitates robust electric energy storage systems for effectively harnessing these resources. Electrochemical energy storage devices, particularly batteries and supercapacitors, have emerged as a focal point of recent research due to their potential to bridge this gap. While supercapacitors are known for their high power density and long cycle life, they typically exhibit limited energy density. Recent advancements have shown that composites combining carbonaceous materials with redox-active nanomaterials can significantly enhance supercapacitors' electrochemical performance. In this context, our research explores the development of hierarchically porous activated carbon nanosheets (JAC) derived from jute, an abundantly available biomass. Using a straightforward pyrolysis process, we have investigated its potential in supercapacitor applications. The prepared JAC, when employed as an electrode material in a symmetric supercapacitor with a glycerol-based bio-electrolyte, demonstrated higher specific capacitance compared to its commercial counterparts. Further innovation was achieved through the introduction of sulfur doping in JAC (S-doped JAC). This novel approach leverages the inherent porous nanosheet morphology of JAC and heteroatom modification to yield exceptional electrochemical performance. Our findings reveal that the S-doped JAC composite, particularly the variant with 25% sublimed sulfur (SJAC-25), significantly outperforms the standard JAC in terms of specific capacitance (230 F/g vs. 130 F/g at 1.0 A/g current density) in a glycerol-KOH bio-based electrolyte. Moreover, a symmetric supercapacitor assembled with SJAC-25 showcased an impressive energy density of 32 Wh/kg at a power density of 500 W/kg, maintaining 28 Wh/kg even at a heightened power density of 2500 W/kg. This demonstrates its capability to retain high energy efficiency under varying power conditions. Additionally, the SJAC-25 based supercapacitor exhibited remarkable durability, with about 94% capacitance retention and 86% Coulombic efficiency after 10,000 charge-discharge cycles. Our research not only highlights the potential of processed bio-waste as a viable material for energy storage but also introduces an advanced, scalable, and straightforward synthesis method. This method could pave the way for the preparation of highly porous and sulfur-doped nanoporous carbon, setting a new benchmark for high-performance electrochemical energy storage applications.

Operando and Ex-Situ Studies of Columbite Electrode Materials

Storing and utilising electricity from renewable sources is of growing importance as we move away from our reliance on fossil fuels. Batteries and supercapacitors are becoming ever more present in our day to day lives; in order to improve the next generation of batteries and supercapacitors, we must understand on an atomic scale what happens to electrode materials upon charge and discharge. In order to do this, we must combine structural and electrochemical studies, using techniques which use both different length scales and different timescales. These experiments are known as operando experiments and are a valuable tool in analysing new materials for energy storage.Transition metal niobates of the columbite structure (MNb2O6, M = transition or alkali earth metal) have previously been studied for their photocatalytic and magnetic properties but recently have garnered interest as negative electrode materials for batteries and supercapacitors.1 In this study, a series of columbite materials have been studied using a range of operando and ex-situ techniques. Samples were prepared using both solid-state synthesis2 and solution methods. Ex-situ X-ray diffraction and scanning electron microscopy were used to characterise the columbites prior to electrochemical testing. Operando X-ray absorption spectroscopy and operando Raman studies have been used to probe the changes in oxidation state of the transition metals and local structure upon charge/discharge. References Yang, X. Zhao, F. Liao, Q. Cheng, L. Mao, H. Fa and L. Chen, Sustain. Energy Fuels, 2021, 5, 3039Garía Alvarado, A. Orera, J. Canales-Vázquez, and J. T. S. Irvine, Chem. Mater., 2006, 18, 3827-3834 Figure 1

Matrimid/MOP-18 Derived Composite Material for High-Energy Aqueous Hybrid Supercapacitor (HSC) Electrodes

The necessity for substantial advancements in electrical energy storage systems is underscored by the increasing demand driven by the extensive integration of renewable energy sources into the grid, the growing popularity of hybrid and electric vehicles, and the escalating safety requirements. Supercapacitors, characterized by their high-power density, inherently superior safety features, and longer cycle life compared to other energy storage systems, are poised to meet these escalating expectations.In this research, an in situ dispersion of Metal-Organic Polyhedra (MOP)-18 in Matrimid is employed to construct a hybrid supercapacitor electrode with enhanced redox activity and improved electrical conductivity. A uniform solution of Matrimid and MOP-18 was electrospun, subsequently carbonized, and activated with CO2 to yield Cu/Cu2O decorated carbon fiber electrode materials. The remarkable solubility of MOP-18 was leveraged to ensure the even dispersion of nanoparticles. The thermally decomposable porous structure of MOP-18 augmented the surface area and electrolyte accessibility of the fabricated electrode. Conversely, Matrimid provided a highly conductive free-standing carbon for the electrode.The amalgamation of these factors culminated in a notable enhancement in capacitance and energy density in a 6 M KOH electrolyte solution. The synthesized composite material achieved a peak capacitance of 253 Fg-1 and an energy density of 12.5 Whkg-1 at a current density of 1 Ag-1. The materials, methods, and techniques employed in the study can be readily scaled up industrially without significant alterations. As illustrated in the study, the use of soluble metal-organic structures to deliver redox-active materials in highly conductive carbon can result in composite electrode materials with synergistic properties. Figure 1

Mangenese Copper Selenide Nanosheet Arrays Derived from Metal-Organic Frameworks for Efficient Solid-State Asymmetric Supercapacitors

Metal chalcogenide nanostructures, particularly metal selenides, have unique properties, such as high electrical conductivity, large specific surface area, exclusive porous networks, and exceptional electrochemical properties compared to traditional nanostructures.1 2 A novel strategy is proposed to design and fabricate hierarchical Manganese copper selenide nanosheet (MnCuSe NS) arrays from metal-organic frameworks (MOFs). The hierarchical MnCuSe NS arrays can deliver enriched electroactive sites and shorten the ion/electron diffusion pathways. When evaluated as positive electrodes for supercapacitor (SC), the MnCuSe NS electrode displayed remarkable electrochemical properties with ultra-high specific capacity of ≈350.4 mA h g− 1 and an areal capacity of ≈0.94 mA h cm− 2 at a current density of 3 mA cm− 2, exceptional rate capability (≈79.5% of the capacity retention at a higher current density of 50 mA cm− 2), and outstanding cyclic stability (≈95.4 % of capacity retention after 10 000 cycles). Most importantly, the assembled MnCuSe NS//FeMnO/NG solid-state asymmetric SC exhibited a wide operating potential window of 1.6 V with an ultra-high volumetric capacity of ≈2.4 mA h cm− 3 at a current density of 3 mA cm− 2, an excellent energy density of ≈71.6 Wh Kg− 1 at a power density of ≈794 W Kg− 1, and ultra-long cycle life (≈93.4 % of capacity retention after 10 000 cycles). This proposed method provides a general protocol to design and fabricate metal selenide nanosheet arrays with superior electrochemical energy storage properties and exceptional cyclic stability, holding significant potential for future energy storage devices in commercial aspects. Keywords: Hierarchical, Metal-organic frameworks, Metal chalcogenide, Energy density, Asymmetric supercapacitorsReference:(1) Han, J. H.; Kwak, M.; Kim, Y.; Cheon, J. Recent Advances in the Solution-Based Preparation of Two-Dimensional Layered Transition Metal Chalcogenide Nanostructures. Chem. Rev. 2018, 118 (13), 6151–6188. https://doi.org/10.1021/acs.chemrev.8b00264.(2) Karuppasamy, K.; Vikraman, D.; Hussain, S.; Kumar Veerasubramani, G.; Santhoshkumar, P.; Lee, S.-H.; Bose, R.; Kathalingam, A.; Kim, H.-S. Unveiling a Binary Metal Selenide Composite of CuSe Polyhedrons/CoSe2 Nanorods Decorated Graphene Oxide as an Active Electrode Material for High-Performance Hybrid Supercapacitors. Chemical Engineering Journal 2022, 427, 131535. https://doi.org/10.1016/j.cej.2021.131535.

(Digital Presentation) On-Chip Micro-Supercapacitors of 3D Carbon Nanotube/Gold Nanocomposites through Silicon-Based MEMS Technology

The high-power and high-frequency response characteristics of supercapacitors have enabled their promising application in fasting charging/discharging scenarios such as power grid stabilization and Internet of Things (IoT). The widespread use of portable electronic devices and the evolution of the IoT have underscored the growing demand for the ongoing miniaturization and enhanced energy autonomy of existing circuit components [1]. Micro-supercapacitors (MSCs) have surfaced as a promising solution to meet these demands, offering superior power density and cycle life compared to similar battery products [2]. However, integrating MSCs with electronic circuits presents significant challenges, often serving as a roadblock to comprehensive system miniaturization. To cater to the requirements of practical application scenarios, particularly in System-in-Package (SiP) and System-on-Chip (SoC) contexts, the fabrication of MSCs requires the use of silicon-based semiconductors or Micro-Electro-Mechanical Systems (MEMS) technology [3]. This strategic approach not only enhances performance but also ensures shorter interconnection distances, more compact dimensions, and increased energy and power density across all components. Emphasizing high power density, elevated energy density, and responsive high-frequency behavior is crucial for the optimal characteristics of MSCs in future applications. As for electrode materials, carbon, which is abundant and cost-effective, has spurred extensive research into various nanostructured carbon-based materials for Electric Double-Layer (EDL) MSCs, including activated carbon, carbon nanotubes (CNTs), carbide-derived carbon, and onion-like carbon [4]. Additionally, transition metal oxides such as ruthenium oxide and manganese oxide, along with conductive polymers like polypyrrole and polyaniline, have proven useful as materials for pseudocapacitive micro supercapacitors [5]. Notably, CNTs fabricated through Chemical Vapor Deposition (CVD) are unequivocally compatible with MEMS microfabrication technology. In the context of EDL MSCs, a dense CNT network structure boosts energy density but impedes ion transport, thereby reducing power density. Conversely, a sparse CNT network structure facilitates ion transport but compromises high-frequency response due to fewer charge transfer paths. Therefore, the development of CNT-based MSCs tailored to practical application needs a more thorough investigation into CNT network structures and their current collector designs.Here, we report the fabrication of on-chip MSCs that are fully compatible with Silicon-based MEMS technology. Figure 1 illustrates the fabrication and characterization process of on-chip MSCs utilizing silicon-based MEMS technology, showing distinct surface morphologies of b-Si nanostructures after CNT growth and Au layer deposition. Figure 2 presents the electrochemical performance of the on-chip MSCs. The CV curves exhibit an ideal rectangular shape at a scan rate of 1 V/s. Even at a high scan rate of 100 V/s, the CV curve maintains a quasi-rectangular shape with minimal distortion, confirming the ultrafast response performance (Fig. 2 (a-b)). The phase angles of the on-chip MSCs are measured to be -68.9° and -66.2° in 1.0 M Na2SO4, and -64.1° and -70.8° in 0.5 M H2SO4 at 120 Hz (Fig. 2 (c)). The absence of a prominent semicircle in the Nyquist plots at high frequencies region implies fast electron transfer and ion diffusion within CNT/Au nanocomposite electrodes. Furthermore, the equivalent series resistances (ESR) are 0.604 Ω·cm2, 0.201 Ω·cm2, 0.504 Ω·cm2, and 0.126 Ω·cm2 for Si-CNT-20 and Si-CNT-20-Au MSCs (Fig. 2 (d)), indicating excellent interfacial contact between the CNT layer and Au current collector and good electrode conductivity. Fig. 2(e) shows that the MSCs deliver a specific capacitance (CA ) of 0.049 mF/cm2, 1.041 mF/cm2, 0.101 mF/cm2, and 1.368 mF/cm2 in 1.0 M Na2SO4 and 0.5 M H2SO4 at 120 Hz, respectively. The relaxation time constant (τ0 ) is calculated to be as short as 1.65 ms for the MSCs (Si-CNT-20-Au), underscoring rapid ion diffusion within electrodes in 0.5 M H2SO4 electrolyte (Fig. 2 (e)).In conclusion, we have successfully used b-Si as the scaffold structure and 3D CNT/Au nanocomposites as the active material for on-chip MSCs application. Significantly, the incorporation of this silicon-based 3D CNT/Au nanocomposite electrode presents promising prospects for the application of MSCs in varied domains, including wearable electronics, IoT devices, and sensor networks.

(Nanocarbons Division Poster Award, 3rd Place) Hybrid Supercapacitance and Stability of Fe-Based Metal-Organic Frameworks/Graphene Oxide Nanoribbons Composite Allover the pH Range

Adopting renewable energy sources is growing fast, and hence it should be accompanied by tremendous efforts to develop energy storage technologies that can mitigate the intermittent nature of these sources. Supercapacitors (SCs) are considered among the most promising technologies for that purpose due to their high durability, power density, and charging/discharging competency. SCs have two types according to their electrochemical charge storage mechanism: pseudocapacitance (PCs) or battery-like behavior and electrochemical double-layer capacitors (EDLCs). The development of next-generation supercapacitors requires a holistic approach that integrates both mechanisms. Because of their huge surface area, porous structure, and abundance of active redox sites, metal-organic frameworks (MOFs) have exceptional potential in energy storage devices. However, due to the MOFs’ low conductivity and stability, they are in need to be mixed with highly conductive and stable materials such as carbon-based ones.In this work, Fe-based MOFs were selected to be responsible for mainly the battery-like contribution to the overall supercapacitance due to the presence of the redox-active sites. Even though little attention has been given to the Fe-based MOFs they showed a promising performance in several solutions, with low stability.1,2 To enhance the Fe-MOFs stability and conductivity and add an EDLC component to the overall capacitance behavior graphene oxide nanoribbon (GONRs) was used. The GONRs' exceptional properties such as ultrathin two-dimensional structures, superior mechanical behavior, strong chemical stability, and high electrical conductivity make them promising materials for supercapacitor applications.In this study, Fe-MOFs were synthesized using a hydrothermal method,3 and GONRs were prepared using an oxidative unzipping method.4 A composite of Fe-MOFs/GONRs was prepared by physical mixing. The physical and chemical properties of the synthesized Fe-MOFs, GONRs, and Fe-MOFs/GONRs were characterized using XRD, SEM, TEM, FT-IR, Raman spectroscopy, and XPS. Since the electrolyte properties have a substantial impact on the supercapacitive behavior and stability of the electrode materials, the specific capacitance of the prepared composites was measured in 1M H2SO4, 1M KOH, 1M K2SO4, and 1M KCl utilizing different evaluation systems (three and two-electrode systems). The Fe-MOFs/GONRs composite showed a significant synergistic effect in comparison to its pure components. Further discussion will be given regarding the pH and ion size/type effect on the supercapacitive performance and stability.

(Invited) Tailoring the Surface Chemistry and Assembling Structure of 2D Materials for Supercapacitors and Batteries

Energy storage devices are important components in portable electronics, electric vehicles, and the electrical distribution grid. Batteries and supercapacitors have achieved great success as the spearhead of electrochemical energy storage devices, but need to be further developed in order to meet the ever-increasing energy demands, especially attaining higher power and energy density, and longer cycling life. Rational design of electrode materials plays a critical role in developing energy storage systems with higher performance. Starting from the classical 2D material - graphene to the other new 2D materials for example MXene, I will introduce some of our recent works about how to design and tune the surface chemistry of 2D materials and how to tailor the structure of 2D materials. Specifically, the interlayer structure and the self-assembled unique structure will be discussed, and the use of various advanced characterization techniques (in situ/operando) to understand the materials and their energy storage mechanisms will be covered in my talk as well. Most importantly, I will also introduce how can we strategically use 2D materials in different applications from battery, supercapacitors to sensors.

Organic Trimer Molecule Electrode as a High-Performance Next-Generation Supercapacitor Material

As greenhouse gas emissions such as CO2 continue to increase on a global scale, countries around the world are making changes to reduce their net emissions. One of the primary actions being taken is attempting to decarbonize the transportation sector by moving away from fossil fuel-powered vehicles and adopting electric vehicles (EVs). Supercapacitors are electrical energy storage devices similar in concept to batteries, however they achieve a higher power output, faster charge and discharge rates, and greater longevity. These properties make them excellent devices to work in tandem with batteries that advance their collective performance capabilities in EVs. Supercapacitors using inorganic materials such as transition metal oxides have been explored extensively and although there have been advancements in the field, they continue to struggle with limitations such as mechanical degradation during cycling, low conductivity which slows the charging-discharging processes, and the utilization of environmentally toxic metals. On the other hand, quinones are a class of organic materials considered as the most promising candidates for organic electrodes due to their ≥ 2 reversible redox-active carbonyl groups, inexpensiveness, ease of structural modifications, and environmental sustainability. However, like many organic materials, they suffer from low electrical conductivity and dissolution in electrolyte. To minimize dissolution while retaining and improving its advantages, polymerizing quinones has become a popular modification alternative, especially via polyimide and polythioether bonds. However, because polymer chains are so large and inherently have low electronic conductivity, polymerizing quinones inhibits charge transfer throughout a matrix with a carbon substrate (i.e., rGO, CNT, carbon black) due to interference with the conductive network.In this research, a smaller molecule was made from covalently bonding two different quinones via imide bonds to make an organic trimer. This helped reduce dissolution in electrolyte compared to its monomeric components via increasing the molecular weight while also improving the energy storage capabilities as a supercapacitor electrode. This is attributed to this molecule retaining the original redox active sites of its monomers and its conjugated network which allows it to achieve a 6-electron transfer mechanism per molecule. Its smaller size compared to a polymer is also hypothesized to reduce the degree of conductivity interruptions it causes when part of a carbon substrate network. While polymer chains can agglomerate easily, decreasing its available specific surface area, this trimer may be more available to participate in Faradaic processes. This research hereby reports an electrode material with very high capacitance (318 Fg-1 at 5 mVs-1) and good cycling stability utilizing a low-cost carbon black substrate for supercapacitor applications to improve the performance of next-generation EVs.

Phase Evolution and Electrochemical Performance of MnS Materials for High-Performance Supercapacitors

Phase Evolution and Electrochemical Performance of MnS Materials for High-Performance Supercapacitors

Na2Zn0.5Co0.5P2O7 diphosphate: Sol-gel synthesis, physico-chemical studies, and prospects as a novel supercapacitor electrode material

For the first time, a mixed-metal diphosphate Na2Zn0.5Co0.5P2O7 has been successfully synthesized via the sol-gel method. The sample was characterized by means of XRD, DTA/TGA, SEM/EDX, UV–vis, Raman, IR and color measurements (CIE-L*a*b*). Its structure was determined through X-ray powder diffraction, in tetragonal system, with space group P42/mnm. The 3D structure of the material consists of infinite chains formed by [Zn/CoO4] tetrahedra and [P2O7] diphosphate units sharing corners. Sodium cations occupy two types of interstitial positions between the infinite chains [Zn/CoP2O7]2-. Raman and Infrared spectra of the studied phosphate have been investigated. A factor group analysis leads to determination of internal modes of the P2O74− anion. Tetrahedral environment of Co2+ ions was confirmed by mean of optical analysis, in which numerous bands in the region 475–675 nm, assigned to the forbidden and allowed d–d transitions of Co2+ are detected and the gap energy is extracted from Tauc and Kubelka-Munk plots. The prepared Na2Zn0.5Co0.5P2O7 diphosphate was extensively investigated for its potential use as an electrode material for supercapacitors. The electrode was prepared by depositing the active material on a conductive substrate (nickel foam) and demonstrated significant electrochemical performance with a specific capacitance of 277 F.g-1 at a scan rate of 5 mV.s-1. This outstanding performance underlines its relevance for supercapacitor applications.

Copper Vanadium Oxide Yolk-Shell Microspheres with Excellent Capacitance and Cycling Performance for Electrochromic Supercapacitor.

Vanadium pentoxide (V2O5) is considered a promising material for electrochromic supercapacitors due to its rich color transitions and excellent electrochemical capacity. However, V2O5 exhibits low electrical conductivity, and its volume changes dramatically during charge-discharge cycles, leading to structural collapse and poor long-term cyclability. These issues have hindered the development and application of V2O5. In this study, copper vanadium oxide yolk-shell microspheres (CVO) were synthesized through a one-step solvent heat treatment with an annealing process. With the doping of copper element, the capacitance, conductivity, and cyclic stability of CVO microspheres were significantly enhanced. Subsequently, the sphere-wire network structure was formed by blending Na2V6O16·3H2O nanowires (NVO), resulting in the formation of CVO/NVO composites. The three-dimensional sphere-wire network efficiently facilitates the acquisition of additional redox sites and strengthens the material-to-substrate bonding. Under the combined influence of these favorable factors, CVO/NVO achieved a high specific capacitance of 39.2 mF cm-2, with a capacitance retention of 84% after 7500 cycles at a current density of 0.7 mA cm-2. The fully inorganic solid-state electrochromic supercapacitor (ECSC), assembled on the basis of CVO/NVO, demonstrates a vivid and clearly distinguishable color change (ΔE* = 37). Even more impressive is the energy storage capacity (18.4 mF·cm-2) and the cycling stability (up to 89% retention after 10,000 cycles) exhibited by the devices. These key performances are superior to those of most of the previously reported V2O5-based ECSCs, opening a promising avenue for the development of V2O5-based electrochromic energy storage devices.

Manganese doped La0.8Ba0.2FeO3 perovskite oxide as an efficient electrode material for supercapacitor

In this study, L0.8Ba0.2Fe1-xMnxO3 (LBFM-x, x = 0.0, 0.2, 0.5, 0.8) perovskite materials were synthesized by a Sol-Gel combustion method and were investigated as an electrode material for a supercapacitor device. The morphology, crystalline structure and electrochemical performance of the samples were studied in detail. The active points, where the electrochemical redox reaction takes place to store faradaic energy, are the oxygen vacancies on the surface of perovskite oxides. Partial substitution in the B-site of the perovskite structure, which is directly related to the oxygen vacancy in BO6 octahedral, is effective in optimizing the electrochemical performance. Based on the results of structural analysis, LBFM-0.2 has the highest concentration of oxygen vacancies; thus, it showed a higher electrochemical performance compared to other samples. The supercapacitors prepared with this electrode material should have an acceptably high specific capacitance of 685 F.g−1 at a current density of 2.0 A.g−1. The partial substitution of Mnn+ at the B-site increases the oxidation state of Fe cations and the mobility of oxygen ions through the oxygen vacancy sites. The electrochemical stability of LBFM-0.2, was evaluated by applying long charge-discharge cycles. After 3000 charge-discharge cycles, the supercapacitor was able to maintain about 94 % of its initial capacity.

2,6-Diaminoanthraquinone modified MXene (Ti3C2Tx)/graphene as the negative electrode materials for ionic liquid-based asymmetric supercapacitors

Due to insufficient energy density, supercapacitors (SCs) with preeminent-power and long cycle stability cannot be implemented in some practical applications. Exploring hybrid materials with redox activity to emerge high specific capacitance in ionic liquid (IL) electrolytes can solve this problem. Herein, we report a redox-organic molecule 2,6-diaminoanthraquinone (DAAQ) modified MXene (Ti3C2Tx)/Graphene (DAAQ-M/G) composite material. With the assist of graphene oxide (GO), MXene and graphene fabricate a three-dimensional (3D) interconnected structure as a conductive framework, which inhibits self-stacking of MXene monolayers and ensures high electronic conductivity. Meanwhile, DAAQ is loaded onto the M/G framework through covalent/non-covalent functionalization. The DAAQ as a spacer effectively enlarges the interlayer spacing of MXene nanosheets, and meanwhile produces reversible redox reactions during charge/discharge processes to provide additional Faradaic contribution to capacity. Therefore, the specific capacitance (capacity) of the DAAQ-M/G as the negative electrode material reaches to 226 F g-1 (306 C g-1) at 1 A g-1 in 1-ethyl-3-methylimidazolium tetrafluoroborate (EmimBF4) electrolyte. Furthermore, an asymmetric supercapacitor (ASC) is assembled using DAAQ-M/G as the negative electrode and self-prepared organic molecule hydroquinone modified reduced graphene oxide (HQ-RGO) material as the positive electrode, with a high energy density of 43 Wh kg-1 at high power density of 1669 W kg-1. The ASC can maintain 80% of initial specific capacitance after 9000 cycles. This research can provide better support to develop advanced organic molecules-modified MXene composite materials for ionic liquid-based SCs.

Facile synthesis of MnMoO4 nanostructures arrays as novel electrode materials for high-performance symmetric and asymmetric supercapacitor

Facile synthesis of MnMoO4 nanostructures arrays as novel electrode materials for high-performance symmetric and asymmetric supercapacitor

Hybrid films composed of reduced graphene oxide and polypyrrole-derived nitrogen-doped carbon nanotubes for flexible supercapacitors

Electrode materials for flexible supercapacitors possessing exceptional and maintaining electrical properties have garnered significant attention in academic research. The graphene oxide (GO) and polypyrrole-derived nitrogen-doped carbon nanotubes (N-CNTs) were mixed to obtain a GO/N-CNTs film. The GO/N-CNTs film was then reduced to prepare a flexible reduced GO (rGO)/N-CNTs film. The specific capacitance of the rGO/N-CNTs film electrode was 223.2 F g−1 at a current density of 0.5 A g−1. The rGO/N-CNTs supercapacitor exhibited a specific capacitance of 130 F g−1 and energy density of 18.04 Wh·kg−1 at a current density of 0.5 A g−1. Furthermore, the capacitance retention of the supercapacitor was 68.7 % when the current density increased to 20 A g−1. In addition, the cyclic voltammetry test indicated that the capacitance retention of the supercapacitor remained at 82.7 % after 8000 cycles, and the capacitance retention still reached 70 % even after bending 600 times. The present study successfully presented the remarkable electrical characteristics of supercapacitors based on rGO/N-CNTs films. Additionally, the investigation has highlighted the noteworthy flexibility of supercapacitors, a feature of considerable significance for applications in wearable technology, portable electronic devices, and flexible displays.

Research progress in the development of transition metal chalcogenides and their composite-based electrode materials for supercapacitors

Research progress in the development of transition metal chalcogenides and their composite-based electrode materials for supercapacitors

Sleuthing the performance of the sustainable mixed metal trichalogenide BaS:Sn2S3:LaS from single source route as an electrode material for charge storage

A novel ternary transition and lanthanide metal composite sulfide (Ba, Sn, and La) has been developed using a single-source precursor method with diethyldithiocarbamate ligand. The resulting BaS:Sn2S3:LaS chalcogenide exhibits a finely tuned band gap of 3.88 eV, reflecting its superior optical performance. This eco-friendly sulfide features an average crystalline size of 17.93 nm and displays a mix of phases. Vibrational analysis reveals distinct transmission peaks corresponding to metal-sulfur bonds. Morphologically, BaS:Sn2S3:LaS composite is characterized by irregularly shaped particles forming a randomly agglomerated mass. The electrochemical charge storage properties of the semiconducting trichalcogenide BaS:Sn2S3:LaS have been investigated using cyclic voltammetry, galvanostatic charge-discharge, and impedance spectroscopy. BaS:Sn2S3:LaS electrode demonstrated impressive performance, storing electrical charge efficiently with a specific capacity of 659.6 F g⁻1 and achieving a power density of up to 3661.65 W kg⁻1. Additionally, the electrode exhibited low resistance, with an equivalent series resistance (Rs) of just 0.43 Ω, indicating efficient ion diffusion across the interface. Given its excellent redox activity and low resistance, BaS:Sn2S3:LaS shows strong potential as an electrode material for supercapacitors and batteries.

Mesoporous carbon particles by biomass waste based on sulfonation and copper oxide functionalization as efficient and stable electrode material for supercapacitor.

Here, the hierarchical mesoporous-activated carbon particles obtained by KOH activation from pistachio shell wastes are modified by both the sulfonation process and CuO doping by hydrothermal heating (CuO@S-doped PSAC) for use as a supercapacitor. It is predicted that the electrochemical performance of the porous carbon electrode material obtained by such CuO doping and sulfonation process will be significantly increased with increased Faradaic capacitance. The electrochemical performance of CuO@S doped PSAC composite is systematically investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge/discharge (GCD) in the presence of 1M H2SO4, 1M Na2SO4, and 1M NaOH as electrolytes. The CuO@S doped PSAC-based electrode shows excellent stability with high specific capacitance up to 397.16 F/g at 0.1 A/g and 92.64% retention. Furthermore, FTIR, SEM, XRD, EDS, and nitrogen adsorption/desorption analyses are used for the characterisation of the obtained composites. Based on a significant supercapacitor performance, the synthesis strategy of carbon-based electrode material containing sulfonation and CuO modifications derived from agricultural biomass waste material is predicted to be a valuable example.

Application of transition metal doped in boron carbide/graphene heterostructures as an electrode for supercapacitors

The density functional theory (DFT) is applied within the current piece of research for exploring the charge storage capacity, quantum or chemical capacitance (QC), electronic structures and the geometry of modified boron carbide (BC3)/graphene (Gr) heterostructure. Also, the impact of doping the Mn atom upon the capacitance behavior of BC3/Gr is explored. Based on the results, doping the Mn atom improved the QC of BC3/Gr. Moreover, doping the Mn atom was more effective than vacancy defect in enhancing the QC of BC3/Gr. The QC of the Mn-doped BC3/Gr was the highest (280.41 F/cm2), which demonstrates its potential application as an encouraging electrode material in supercapacitors (SCs). Based upon the DOS around the Fermi level, doping the Mn atom could be the reason for the increase in the QC. Finally, the results can provide useful insights into designing high-capacitance SCs.