Next-generation Supercapacitors Research Articles

Electrochemical performance enhancement of MnO2 nanowires through silver incorporation for next-generation supercapacitors

AgxMnO2 nanowires offer a potential solution to improve conductivity and stability of supercapacitor electrode.

Waste polyethylene terephthalate plastic derived Zr-MOF for high performance supercapacitor applications

The chemical conversion of plastic waste into metal-organic framework (MOF) materials has emerged as a significant research field in addressing issues associated to the environment and the economy. The significant advantages of MOFs as electrode material for energy/supercapacitors arises from their extensive surface area and notable porosity. The present study involved the synthesis of Zirconium-Metal Organic Frameworks (Zr-MOF) by the solvothermal method, utilizing plastic waste in the form of Polyethylene terephthalate (PET) bottles. The morphological and structural characteristics of the Zr-MOF were inspected through several analytical techniques, including scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy analysis. The as prepared Zr-MOF demonstrated very high specific surface area of 927.567 m2 g−1 with mesoporous nature of the materials estimate by BJH method. The electrochemical characteristics of the Zr-MOF in 3-electrode system exhibited a notable specific capacitance of 822 F g−1 when subjected to a low scan rate of 2 mV S−1, while the specific capacitance estimated through galvanostatic charge-discharge exhibited an enhanced value of 890 F g−1 at a current density of 0.5 A g−1. Additionally, the working electrode composed of Zr-MOF demonstrated noteworthy capacitance retention of 92% after 5000 charge discharge cycles. This research presents novel opportunities for the utilization of waste PET bottles in fabrication of highly functional Zr-MOF, aiming to advance the development of next-generation supercapacitors and environmental remediation.

Anomalous Increase in Double Layer Capacitance in Ionic Liquid-Metal Salt Blends

Supercapacitors provide exiting opportunities for the future of energy storage due to a combination of fast charge-discharge kinetics, high safety, and long device lifetimes. Yet, current supercapacitors have energy densities that are orders of magnitude lower than those of lithium-ion batteries, relegating them to niche uses such as regenerative braking systems. While ionic liquids have shown promise as next generation electrolytes in supercapacitors due to their nonflammable nature, large electrochemical stability window, and predicted large capacitances, neat ionic liquids have capacitances ranging from 5 to 20 µFcm-2 which does not compete with current supercapacitors made with cheaper electrolytes. In this talk, I will discuss how we have substantially increased the capacitance of ionic liquid-electrode interfaces though the addition of metal salt additives containing Li, Na, K, and Mg ions. We maintain the large voltage window while increasing the capacitance to up to 80 µFcm-2 at both positive and negative polarizations of gold electrodes. By conducting complementary surface structuring studies, we elucidate molecular assembly at charged surfaces to understand ion behavior when only surrounded by other ions in solution. We hypothesize that the introduction of metal salts interrupts ion aggregates that exist in concentrated electrolytes, reducing the screening lengths in ionic liquids and thus increasing capacitance. Overall, our study demonstrates that ionic liquids may have transformative promise for next-generation supercapacitors, and highlights new paradigms for tuning interfacial properties via modulation of ion coordination in concentrated electrolytes.

High pseudocapacitance electrode enabled by heterovalent doping and surface coating for rapid charge storage

With admirable energy storage kinetics and high capacitance, pseudocapacitive electrodes have been regarded as promising candidates to replace active carbon materials for next-generation supercapacitors. Unfortunately, these materials usually present lower capacitance compared to the Ni/Co-based battery-type materials, and insufficient cycling lifespans due to repeat surface redox reactions. Here, we employ Fe doping and surface coating to construct a high-capacitance robust pseudocapacitive WO3-based electrode (10-Fe-WO3/PANI). Heterovalent doping breaks the octahedral symmetry of WO3 and effectively boosts the reversible capacitance of WO3 due to Jahn-Teller distortion, creating abundant active sites for energy storage. Polyaniline (PANI) coating enhances the structural durability and ion diffusion kinetics of WO3 in the acid electrolyte, promoting long-term cycling performance. As expected, the optimized electrode can deliver a high specific capacitance of 4006 mF cm−2 at 5 mA cm−2, which is about five-fold higher than that of a pure WO3 electrode (733.7 mF cm−2) and can steadily work for 10,000 cycles without apparent capacitance decay. The full device using polypyrrole (PPy) as the cathode exhibits intriguing energy/power density and cycling lifespans, demonstrating the application potential of this material. This work may enlighten the development of cationic doping and advanced pseudocapacitive materials design in electrochemical energy storage fields.

Powering up the energy storage: Exploring the potential of Graphitic Carbon Nitride-Strontium Oxide Nanohybrid for next-generation energy and photocatalytic applications

The world today is facing an unprecedented environmental and energy crisis. To tackle these issues, there is a growing focus on developing advanced energy storage and photocatalytic systems. In this study, we explored the potential of novel graphitic carbon nitride‑strontium oxide nanohybrids (GCN-SrO NH) for next-generation supercapacitor and photocatalytic applications. The green microwave-assisted approach was applied to synthesize desired materials. The GCN-SrO NH electrode exhibited an excellent specific capacitance of 482 F/g at 0.5 A/g with an energy density of 16.7 Wh/kg and a power density of 146.2 W/kg. A two-electrode symmetric supercapacitor was assembled to further examine the capacitive performance of GCN-SrO NH in practical applications. Consequently, the GCN-SrO NH//GCN-SrO NH symmetric supercapacitor device displayed an exceptional specific capacitance of 242 F/g at 0.5 A/g. The device delivered the highest energy density at 18.9 Wh/kg with an outstanding power density of 187.5 W/kg. The practicability of the assembled device was also demonstrated by glowing red LED. Moreover, GCN-SrO NH based catalyst showed excellent degradation efficiencies (97.21 %, 98.59 %, and 92.9 %) against methylene blue (MB), methyl orange (MO), and rhodamine B (RhB) dyes under visible light. This research reveals the potential of GCN-SrO NH for cutting-edge energy storage and environmental applications.

Preparation of high-performance asymmetric supercapacitors based on NiCo2S4 nanospheres and CuO-MOF nanosheets on carbon fibers

Highly efficient and low-cost supercapacitors (SCs) with excellent energy storing capacity are highly demanded to fabricate modern portable and wearable electronic devices. Herein, NiCo2S4 nanospheres and CuO-MOF nanosheets were fabricated on flexible carbon fibers (CF) by one-step hydrothermal solvent method, employed as two effective electrode materials. Accordingly, the cathode (CuO-MOF@CF) and anode (NiCo2S4@CF) plays a prominent role in energy storage properties due to large specific surface areas, by providing comparative capacities of 953 F/g and 1571 F/g, respectively. Remarkably, benefited from the synergistic effect, the designed asymmetric supercapacitor (SC) CuO-MOF@CF//NiCo2S4@CF exhibits a voltage window of ∼3.0 V, which demonstrates an impressive specific capacitance of 2426.6 F/g at a current density of 700 mA/g, the maximum energy density (ED) of 164.85 Wh/kg, as well as an excellent power density (PD) of 3780 W/kg. Even after 10,000 cycles of charge and discharge, the specific capacitance retention rate still reaches 96.43 %. This study offers a cost-effective and simple strategy for rational design of energy storage configurations for favorable electrochemical performances, emphasizing great potentials in next-generation supercapacitors application.

Ultrasounds-assisted solvothermal synthesis of Ni-Co-Mn MOFs/PANI-CNTs nanocomposites with enhanced electrochemical energy storage performance

Among various energy storage devices, one of the emerging classes to be considered nowadays is advanced eco-friendly supercapacitors. Despite vast research regarding their electrochemical performance, there is still room for further refinement. Here, such an attempt has been made by producing nanocomposites of NiCoMn ternary transition metal-organic frameworks (MOFs) with conductive-natured carbon nanotubes (CNTs) functionalized with polyaniline (PANI). A rather different approach i.e., ultrasounds assisted solvothermal method has been employed to prepare the MOFs and their nanocomposites with varying concentrations (0, 20, 40, 60 mg) of PANI functionalized CNTs (PC). A comparison analysis suggests that NiCoMn/PC-40 (40 mg PANI-CNTs) has shown excellent electrochemical performance. In the material of worth attention, the formation of flower-like morphology and crystallinity was explored and confirmed by SEM and XRD characterizations. FT-IR analysis facilitated the exploration of compositional and functional groups of the best-performing material. The large cyclic area, highest specific capacity, excellent stability, less ion transport resistance, and excellent morphology proved NiCoMn/PC-40 as an excellent next-generation supercapacitor battery-grade material with the dominance of diffusive response (71.7%). It has been shown 1194 C/g of specific capacity with an extraordinary energy density of 82 Wh/kg and 1105 W/kg of power density by the NiCoMn/PC-40. At 20 A/g, 100% cyclic stability after 5000 charge/discharge cycles with 97.5% columbic efficiency was achieved. In essence, the excellent electrochemical performance, ease of fabrication, and affordable cost can provide a breakthrough in value addition of NiCoMn/PC-40 worth as a proficient energy storage material.

Natural Solid-State Hydrogel Electrolytes Based on 3D Pure Cotton/Graphene for Supercapacitor Application.

A conductive cotton hydrogel with graphene and ions can come into contact with electrodes in solid electrolytes at the molecular level, leading to a more efficient electrochemical process in supercapacitors. The inherently soft nature of cotton mixed with hydrogel provides superior flexibility of the electrolyte, which benefits the devices in gaining high flexibility. Herein, we report on the current progress in solid-state hydrogel electrolytes based on 3D pure cotton/graphene and present an overview of the future direction of research. The ionic conductivity of a complex hydrogel significantly increased by up to 13.9 × 10-3 S/cm at 25 °C, due to the presence of graphene, which increases ionic conductivity by providing a smooth pathway for the transport of charge carriers and the polymer. Furthermore, the highest specific capacitance of 327 F/g at 3 mV/s was achieved with cyclic voltammetry measurement and a galvanostatic charge-discharge measurement showed a peak value of 385.4 F/g at 100 mA/g current density. Furthermore, an electrochemical analysis demonstrated that a composite cotton/graphene-based hydrogel electrolyte is electrically stable and could be used for the design of next-generation supercapacitors.

Construction of 3D flower-like SnS particles anchored Ni-metal-organic framework composite: A novel positive electrode material for high-performance asymmetric supercapacitors

Metal-organic frameworks (MOFs) have gains particular consideration as electrode material in supercapacitors owing to their porous nature, tunable structure, and occurrence of many active sites. However, some pristine MOFs' poor electrical conductivity and stability confine their potential application in supercapacitors. In this work, a new type of Nickel-MOF-based tin sulfide composite (Ni-MOF/SnS) is prepared using the simple hydrothermal route and studied its applicability in supercapacitors. The physicochemical characterizations of the as-prepared Ni-MOF/SnS composite confirm the perfect synthesis and formation of porous 3Dimensional (3D) flower-like SnS particles anchored Ni-MOF hexagonal rods-like morphology. The existing porous structure and SnS particles in the Ni-MOF/SnS composite deliver many active sites to perform the electrochemical reactions, achieving an excellent specific capacity value of 1440 C/g at 1 A/g. Also, Ni-MOF/SnS composite electrode maintains 95 % of its specific capacity value up to 8000 charge-discharge cycles at 3 A/g. Furthermore, the as-fabricated Ni-MOF/SnS//Activated carbon asymmetric device delivers the specific capacity of 228 F/g at 1 A/g, revealing a high energy and power density of 81.06 Wh/kg and 1823.8 W/kg, respectively. These findings demonstrate that the Ni-MOF/SnS composite represents a suitable electrode material for the next generation of supercapacitors.

Engineering in the morphology of Ni3S2 via doping of Ce with different concentration to improve the capacitive properties

Transition metal oxides (TMOx) have garnered focused for their potential usage in supercapacitors attributed to their high specific capacitance (Cs), safety, economical, and notable electrochemical activity. But their low cycling stability has been increased by doping strategy. In this research, we report the fabrication of Ni3S2 (NS) and Ce doped Ni3S2 (CNS) with different concentration (0.1, 0.3 and 0.5 mmol) via hydrothermal method without the use of surfactants. Structure, morphology, and electrochemical performances of pure and Ce doped Ni3S2 nanostructures have been investigated. The crystalline structure has been investigated by powder X-ray diffraction (PXRD) and morphological behavior with Scanning electron microscopy (SEM). The electrochemical finding suggests that the specific capacitance (Cs) of a Ni3S2 nanomaterial doped with 0.3 Ce is studied by using a three-electrode setup exhibited the maximum capacitance of 2349.10 F g−1 and energy density (Ed) of 72.07 Wh kg−1 at 1 A g−1. The symmetric behavior of 0.3 Ce doped Ni3S2 electrode also determined with a two-electrode device made from 0.3 Ce doped Ni3S2 which display a higher specific capacitance (Cs) of 1139.22 F g−1 at 1 A g−1. This highlights the electrocatalytic potential of an symmetric device based on 0.3-CNS for next-generation supercapacitors.

Polynaphthalene-Based Oxazaborinine Complexes Formulated as Red Light Emitters and High-Performance Asymmetric Supercapacitors.

Developing a solid organic emitter based on an oxazaborinine complex with improved photophysical characteristics has become essential to fulfilling the rising need for optical and electrochemical technology. Two oxazaborinine complexes (TNB (a tri-naphthalene boron complex) and DNB (a di-naphthalene boron complex)) decorated with naphthalene and triphenylamine have been developed, which show emission in the red light region in the solid phase. Their effectiveness as asymmetric supercapacitor electrodes in aqueous electrolytes is also being studied. Polynapthaldimine-substituted DNI (di-naphthalene imine) and TNI (tri-naphthalene imine) have been initially synthesized and converted to a N,O-linked boron complex. TNB in solids (λem 660 nm) and the polydimethylsiloxane (PDMS) composite (λem 632 nm) emit pure red light. The optimized structure has been generated, and the HOMO-LUMO energy was calculated with the help of density functional theory (DFT). Due to the higher conjugation effect and lower HOMO-LUMO energy difference, TNB could be used as a supercapacitor electrode. In a three-electrode configuration, TNB has a maximum specific capacitance of 896.25 F/g. Furthermore, an asymmetric supercapacitor device (ASC) was fabricated in an aqueous electrolyte using TNB as a positive electrode having a high specific capacitance of 155 F/g. Even in an aqueous electrolyte, the ASC device reached the operating potential window of 0 to 1.4 V with an enhanced energy density of 42.19 W h/kg and ∼96% cyclic stability after 10 000 cycles. The reported oxazaborinine complex and its electrochemical efficiency in aqueous electrolytes make it ideal for supercapacitor applications and directly impact the development of advanced electrodes for next-generation supercapacitors.

Recent Progress of 2D Layered Materials in Water-in-Salt/Deep Eutectic Solvent-Based Liquid Electrolytes for Supercapacitors.

Supercapacitors are candidates with the greatest potential for use in sustainable energy resources. Extensive research is being carried out to improve the performances of state-of-art supercapacitors to meet our increased energy demands because of huge technological innovations in various fields. The development of high-performing materials for supercapacitor components such as electrodes, electrolytes, current collectors, and separators is inevitable. To boost research in materials design and production toward supercapacitors, the up-to-date collection of recent advancements is necessary for the benefit of active researchers. This review summarizes the most recent developments of water-in-salt (WIS) and deep eutectic solvents (DES), which are considered significant electrolyte systems to advance the energy density of supercapacitors, with a focus on two-dimensional layered nanomaterials. It provides a comprehensive survey of 2D materials (graphene, MXenes, and transition-metal oxides/dichalcogenides/sulfides) employed in supercapacitors using WIS/DES electrolytes. The synthesis and characterization of various 2D materials along with their electrochemical performances in WIS and DES electrolyte systems are described. In addition, the challenges and opportunities for the next-generation supercapacitor devices are summarily discussed.

High-Performance Supercapacitors: A Comprehensive Review on Paradigm Shift of Conventional Energy Storage Devices

The enormous demand for energy due to rapid technological developments pushes mankind to the limits in the exploration of high-performance energy devices. Among the two major energy storage devices (capacitors and batteries), electrochemical capacitors (known as ‘Supercapacitors’) play a crucial role in the storage and supply of conserved energy from various sustainable sources. The high power density and the ultra-high cyclic stability are the attractive characteristics of supercapacitors. However, the low energy density is a major downside of them, which is also responsible for the extensive research in this field to help the charge storage capabilities thrive to their limits. Discoveries of electrical double-layer formation, pseudocapacitive and intercalation-type (battery-type) behaviors drastically improved the electrochemical performances of supercapacitors. The introduction of nanostructured active materials (carbon-/metal-/redox-active-polymer/metal-organic/covalent-organic framework-based electrode materials), electrolytes (conventional aqueous and unconventional systems) with superior electrochemical stability and unprecedented device architectures further boosted their charge storage characteristics. In addition, the detailed investigations of the various processes at the electrode–electrolyte interfaces enable us to reinforce the present techniques and the approaches toward high-performance and next-generation supercapacitors. In this review, the fundamental concepts of the supercapacitor device in terms of components, assembly, evaluation, charge storage mechanism, and advanced properties are comprehensively discussed with representative examples.

Boosting the electrochemical activities of MnO2 for next-generation supercapacitor application: Adaptation of multiple approaches

A novel Ag-MnO2/MXene on nickel foam (Ag-MnO2/MXene@NF) electrode has been developed by incorporating hydrothermal and post-sonication processes. Ag-doping, MXene reinforcement, nanotechnology approaches, and highly porous current collector (Nickel foam) play a decisive role in boosting the overall activity of the Ag-MnO2/MXene@NF. The Ag-doping tunes the band structure of MnO2 and intrinsically improves its specific conductivity. At the same time, the sandwiching of Ag-MnO2 NWs between the MXene sheet's voids and their dispersion over the MXene sheet’s surface led to the formation of a hetero-structured composite with superb conductivity, a high surface area, lower crystallinity, and structural openings. The nanostructured nature of MnO2 (NWs) and their addition to MXene, a conductive and porous matrix, resulted in better capacitance retention and faster ion diffusion. The nano-sized and spongy structure of the Ag-MnO2/MXene@NF not only exposes the bulk of the electrode for charge storage but also buffers the electrode from pulverization as a result of tedious cyclic tests and facilitates the electrolyte ions' mobility. These induced features enabled the Ag-MnO2/MXene@NF to show a higher capacitance of 1188 F g−1 @ 1Ag−1, impressive rate capability (85.8 % @9 A g−1), and superb cyclic activity of 96.4 % after 6000 tests. The combination of various techniques boosts the overall electrochemical performance of our developed Ag-MnO2/MXene electrode, making it an acceptable option for use in advanced energy storage devices.

Size Effect of Electrolyte Ions on the Electric Double-Layer Structure and Supercapacitive Behavior

Finding a viable electrolyte for next-generation supercapacitors is of primary importance for developing supercapacitors with high power and energy densities. Herein, we synthesized a conducting salt, tetramethylphosphonium tetrafluoroborate (TMPBF4), and compared the electrochemical characteristics of supercapacitor devices containing TMPBF4 or 1,1-dimethylpyrrolidinium tetrafluoroborate (DMPBF4). The TMPBF4 salt was selected based on the generally accepted design rule that smaller ions and solvation shells contribute to higher energy and power densities. However, at a low current density (0.1 A g–1), supercapacitors with TMPBF4 in acetonitrile (AN) exhibited a slightly lower capacitance (24.6 ± 0.1 F g–1) than those with DMPBF4 (25.0 ± 0.2 F g–1). Clarification of this behavior using electrochemical and theoretical methods revealed that the total capacitance is influenced by not only the size of the ions but also the degree of cation–anion interactions near the electrodes. By contrast, at a high current density of 10 A g–1, supercapacitors with TMPBF4 showed an 18% increase in capacitance relative to those with DMPBF4. Supercapacitors with TMPBF4 exhibited both high capacitance and a remarkably long cycle life (10,000 cycles) at a high working voltage (3.2 V) and high current density (10 A g–1). Furthermore, supercapacitors utilizing TMPBF4/AN provided a sufficiently fast frequency response for 60 Hz alternating current (ac) line filtering. These insights into the influence of the investigated electrolyte salts on the formation of electric double-layer structures offer design rules for developing electrolytes for supercapacitors.

One-Step Solvothermal Synthesis by Ethylene Glycol to Produce N-rGO for Supercapacitor Applications.

Graphene and its derivatives have emerged as peerless electrode materials for energy storage applications due to their exclusive electroactive properties such as high chemical stability, wettability, high electrical conductivity, and high specific surface area. However, electrodes from graphene-based composites are still facing some substantial challenges to meet current energy demands. Here, we applied one-pot facile solvothermal synthesis to produce nitrogen-doped reduced graphene oxide (N-rGO) nanoparticles using an organic solvent, ethylene glycol (EG), and introduced its application in supercapacitors. Electrochemical analysis was conducted to assess the performance using a multi-channel electrochemical workstation. The N-rGO-based electrode demonstrates the highest specific capacitance of 420 F g-1 at 1 A g-1 current density in 3 M KOH electrolyte with the value of energy (28.60 Whkg-1) and power (460 Wkg-1) densities. Furthermore, a high capacitance retention of 98.5% after 3000 charge/discharge cycles was recorded at 10 A g-1. This one-pot facile solvothermal synthetic process is expected to be an efficient technique to design electrodes rationally for next-generation supercapacitors.

Facile synthesis of petal-like MnMoO4/Ni(OH)2 ultrathin nanosheets for high-performance asymmetric supercapacitor

Petal-like MnMoO4/Ni(OH)2 ultrathin nanosheets were synthesized via a facile hydrothermal method, and their electrochemical performance was evaluated. Electrochemical analysis indicated that the specific capacitance was 1999.6F/g at 1 A/g, with an excellent cycling stability of 97.2 % over 5000 cycles at 10 A/g. An asymmetric supercapacitor MnMoO4/Ni(OH)2//AC exhibited a good energy density of 60.2 W-h/kg at 800 W/kg. Hence, the MnMoO4/Ni(OH)2 electrode material is a potential candidate for the design of high-performance next-generation supercapacitors.

Iron doped Gd2Zr2O7 hierarchical nanoflakes arrays as robust electrodes materials for energy storage application

The current work highlights the use of Fe doped Gd2Zr2O7 electrode materials to increase the supercapacitive properties. A hydrothermal technique is used to successfully produce pure and doped Gd2Zr2O7 (Fe = 5 %, 10 %, and 20 %) electrode material. Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) along with Brunner–Emmet–Teller (BET) testing are employed for examining the crystal structure, specific surface area, morphology, and chemical composition of investigated materials. On the other hand, Fe doping altered the crystal structure and shape of the Gd2Zr2O7 flakes like network. Additionally, the 20 % Fe doped Gd2Zr2O7 electrode material acquires great specific surface area with enhanced exposed active sites of the fabricated material on the surface. On the contrary, cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) & electrochemical impedance spectroscopy (EIS) is used for assessing electrochemical performance of the fabricated electrodes. According to the experimental results, 20 % Fe-doped Gd2Zr2O7 electrode material exhibited the best electrochemical performance, for example the specific capacitance of 2561 F g−1 at current density of 10 mV s−1 with energy density of 54 Wh kg−1 is obtained, and retention was 84 % after 30 h. Due to its high Csp as well as long durability, 20 % Fe-doped Gd2Zr2O7 electrode material is an excellent candidate for next-generation supercapacitor material.

High-Performance Flexible Energy Storage Devices Based on Graphene Decorated with Flower-Shaped MoS2 Heterostructures

MoS2, owing to its advantages of having a sheet-like structure, high electrical conductivity, and benign environmental nature, has emerged as a candidate of choice for electrodes of next-generation supercapacitors. Its widespread use is offset, however, by its low energy density and poor durability. In this study, to overcome these limitations, flower-shaped MoS2/graphene heterostructures have been deployed as electrode materials on flexible substrates. Three-electrode measurements yielded an exceptional capacitance of 853 F g-1 at 1.0 A g-1, while device measurements on an asymmetric supercapacitor yielded 208 F g-1 at 0.5 A g-1 and long-term cyclic durability. Nearly 86.5% of the electrochemical capacitance was retained after 10,000 cycles at 0.5 A g-1. Moreover, a remarkable energy density of 65 Wh kg-1 at a power density of 0.33 kW kg-1 was obtained. Our MoS2/Gr heterostructure composites have great potential for the development of advanced energy storage devices.

Tetranitro-substituted cobalt phthalocyanine immobilized on reduced graphene oxide as supercapacitor electrode material with enhanced capacitance

Recent progress in the construction of metal phthalocyanines (MPcs) has opened up new strategies for energy storage applications. Since MPcs possess excellent redox activities, we have developed a simple ultrasound process to fabricate nanocomposites based on different ratios of tetranitro-substituted cobalt phthalocyanine (Co(NO2)4Pc) and reduced graphene oxide (rGO) and evaluated their energy storage performance for supercapacitor. A maximum specific capacitance of 150.22 F g−1 was achieved for the Co(NO2)4Pc-rGO 1/6 electrode at high current density (4 A g−1), which is 1.6 and 1.8 times higher than the individual materials, respectively. This great electrochemical activity is attributed to the synergistic effect between two components. Moreover, this electrode manifested outstanding cycling stability (retained 111.6 % of its initial capacitance after 5000 cycles). The experimental findings ensure the potential application of Co(NO2)4Pc-rGO composite as an electrode material for the next-generation supercapacitor applications.