Conventional Supercapacitors Research Articles

Carbon Nanotube Interconnected Polypyrrole@ E‐MXene Organic‐Inorganic Hybrids for Interdigitated In‐Plane Supercapacitor Applications

AbstractIn recent times, there has been a growing focus on developing flexible electrochemical energy storage devices to address the booming demands of wearable electronics. Supercapacitors (SC) are prized among the electrochemical energy storage devices for their remarkable specific capacitance and power density. Conventional flexible SCs predominantly rely on various carbon based materials as electrodes and current collectors for these applications. Despite this, a novel approach is adopted to fabricate a flexible supercapacitor from laser‐induced graphene with a ternary hybrid of polypyrrole with Mxene and carbon nanotube (PPy@E‐MXene/f‐CNT) as an electrode material. The fabricated in‐plane supercapacitor achieves an outstanding specific capacitance of 66.6 mF cm−2 (83.25 mFg−1) with an energy density of 4.5 µWh cm−2 (with a power density of 0.03 mW cm−2). This innovative approach presents a promising avenue for developing flexible and wearable energy storage solutions. Further, Density Functional Theory (DFT) simulations are carried out to support the experimental findings and elucidate the structural, electronic, and electrochemical properties of the hybrid systems.

Implementation of phosphonium salt for high-performance supercapacitors from room to ultra-low temperature conditions

Conventional supercapacitors encounter limitations in operating voltage and performance at low temperatures due to poor ionic conductivity and diminished interfacial dynamics in electrolytes. In this study, we synthesized the phosphonium salt 5-phosphinaspiro[4.4] nonane tetrafluoroborate (PSNBF4) for the first time. We extensively characterized the physical and electrochemical properties of PSNBF4 in acetonitrile (AN) and propionitrile (PN) as electrolytes, assessing their performance in supercapacitors at room temperature and − 40 °C. The results demonstrate PSNBF4 electrolytes exhibit high solubility, outstanding ionic conductivity (1 M PSNBF4/AN: 49.8 mS cm−1; 1 M PSNBF4/PN: 27.5 mS cm−1), and high electrochemical stability, contributing to good capacitance retention after 500 h of floating tests at 25 °C. Supercapacitors using PSNBF4/AN retained 78 % of their capacitance at 3.1 V, whereas those with PSNBF4/PN maintained 68 % at 3.2 V. Impressively, these supercapacitors performed exceptionally well at −40 °C, displaying excellent cycle stability and high capacitance retention at elevated voltages. Supercapacitors with PSNBF4/AN retain 96.6 % of their capacitance at 3.2 V, while PSNBF4/PN retained 93.4 % of their capacitance at 3.4 V after floating for 500 h. These results demonstrate PSNBF4-based supercapacitors can operate effectively at high voltages in both room and extremely low temperatures, addressing a significant challenge in commercial supercapacitor applications.

Exploring the Formulation and Efficacy of Phosphazene-Based Flame Retardants for Conventional Supercapacitor Electrolytes.

The formulation of safe electrolytes for supercapacitors based on phosphazene used as a flame-retardant (FR) is carried out. 3 molecules are used: hexafluorocyclotriphosphazene (FR1), (ethoxy)pentafluorocyclotriphosphazene (FR2) and pentafluoro(phenoxy)cyclotriphosphazene (FR3). A comparative study on the efficacy from a safety point of view is performed to determine the minimum percentages of each to be used in a conventional acetonitrile (ACN)/1.0 M tetraethylammonium tetrafluoroborate (Et4NBF4) electrolyte to make it non-flammable. Flammability tests have shown that 5 %FR1, 15 %FR2 or 20 %FR3 are required to do that. The FTIR coupled to the TGA as well as the measurements of surface tensions and contact angles showed that the FRs tend to protect the surface of the electrolyte. The transport properties always remain good, superior to PC/1.0 M Et4NBF4 for example, and the electrochemical stability windows determined in 3-electrode cells with platinum or activated carbon are at least 2.5 V. The cycling performances are also interesting because the AC|AC EDLCs made in this study are compatible with these FRs, which makes it possible to operate devices providing energies and powers of 23.0 Wh kg-1 and 3.7 kW kg-1 with the electrolytes based on FR1 or FR2 between 0 and 2.5 V.

Surface-Functionalized Carbon Linker-Mediated Assembly for Preparing Pseudocapacitive Binder-Free Textile Electrodes

High-performance textile electrodes for pseudocapacitors demands efficient integration of electrochemically active materials and conductive fillers onto current collectors. This is particularly challenging when applying nano-sized, high-energy pseudocapacitive materials due to their poor electrical conductivity. Our study presents a novel method for fabricating such electrodes by directly assembling high-energy nanoparticles (MnOx NPs) onto three-dimensional textile current collectors using surface-functionalized carbon nano-oligomer (CNOs), thereby eliminating inactive or insulating organic components . The assembly process, based on direct interfacial multidentate interactions between MnOx NPs and CNOs, ensures a uniform nano-level distribution across the entire surface of metal textile current collectors. The resulting positive electrodes, referred to as (MnOx NP/CNO)-based textile, demonstrate an exceptional areal capacitance of approximately 1,725 mF cm−2 at 5.0 mA cm−2, which can be further enhanced to around 3,244 mF cm−2 at 10 mA cm−2 through multi-stacking. Moreover, when paired with negative electrodes ((Fe3O4 NP/CNO)-based textile) prepared using the same method, asymmetric full-cell devices exhibit remarkable areal energy/power densities surpassing those of conventional slurry-cast supercapacitors.

Redox-active a pyrene-4,5,9,10-tetraone and thienyltriazine-based conjugated microporous polymers for boosting faradaic supercapacitor energy storage

Conventional supercapacitor electrodes typically suffer from drawbacks such as low energy density, short cycle life, and poor conductivity. In contrast, conjugated microporous polymers (CMPs) present a more advantageous option, providing higher surface area, greater cycle stability, and enhanced electrical properties. Utilizing pyrene-4,5,9,10-tetraone (PyTE) as a key redox-active component, we successfully prepare pyrene-4,5,9,10-tetraone-thiophene polymer (PyTE-Th Polymer) and Thienyltriazine-pyrene-4,5,9,10-tetraone conjugated microporous polymer (TTh-Ph-PyTE CMP). This particular set of materials has been tailored for supercapacitor applications, employing a nitrogen-rich triazine, conductive thiophene (Th), and redox-active pyrene-4,5,9,10-tetraone (PyTE), a creation through simple Suzuki coupling conditions. PyTE-Th Polymer and TTh-Ph-PyTE CMP exhibit comparable BET surface areas and demonstrate good thermal stability, with char yields exceeding 62 wt% for each material. Electrochemical measurements reveal that TTh-Ph-PyTE CMP, featuring a triazine group with abundant heteroatoms, exhibited exceptional cycle stability of 90 % after 5000 cycles at 10 A g−1 and a specific capacitance of 1041 F g−1 (1 A g−1). Notably, TTh-Ph-PyTE CMP portrays the maximum specific capacitance at 1 A g−1 compared to PyTE-Th polymer (486 F g−1) and other porous materials, suggesting a synergistic effect of redox-active units and abundant heteroatoms.

Tailoring flower-like NiCo LDH/MoS2/HPC ternary hierarchical heterostructures electrodes with enhanced energy density for aqueous asymmetric supercapacitor

The imperative quest for renewable energy sources and advanced energy storage technologies has arisen amidst the escalating perils of climate change and dwindling fossil fuel reserves. In the realm of energy storage technologies, asymmetric supercapacitor (ASC) has garnered significant attention owing to its high energy density and power density. In the quest for advanced electrode materials for ASC, the integration of 2D layered heterostructures on hierarchical porous carbon (HPC) substrates has emerged as a promising approach to enhance the electrochemical performance. Herein, a highly innovative hierarchical NiCo LDH/MoS2/HPC heterostructure was successfully synthesized using a simple two-step hydrothermal method for the electrode materials of ASC. Benefiting from the unique hierarchical heterostructure of NiCo LDH/MoS2/HPC composite and the synergistic effect between the components, it reveals an exceptional specific capacitance of 2368 F/g at 0.5 A/g in a three-electrode system, which significantly exceeds that of conventional supercapacitor electrodes. Additionally, the ASC device of NiCo LDH/MoS2/HPC//HPC achieves remarkable specific capacitance of 236 F/g at 0.5 A/g and an impressive energy density of 84 Wh/kg at a power density of 400 W/kg, as well as superior cyclic stability. This study not only demonstrates the effectiveness of incorporating MoS2 and NiCo LDH into a carbon-based framework for supercapacitor applications but also opens avenues for designing more efficient energy storage devices.

Current trends in micro‐supercapacitor devices

AbstractRecently, efforts have been made to design miniaturized energy storage devices according to custom requirements. The application of micro‐electronic equipment has increased significantly in information technology and biotechnology. Microelectromechanical systems, nanoelectromechanical systems, maintenance‐free wireless sensor networks, implantable medical devices, micro‐robots, and integrating energy conversion devices require micropower sources in small dimensions. Conventional supercapacitor devices cannot fulfill such high‐power demand, but miniaturization within the microscale helps enhance the working efficiency due to the shortening of diffusion path length. Micro‐supercapacitors (MSCs) in the micron to centimeter dimension range integrated with circuits and microelectronic components have gained great interest due to their high‐power density, high‐frequency response, and long cycling stability. Research on the design and fabrication of MSCs has progressed enormously. Integrating MSCs with other electronic units helps to achieve a highly efficient self‐powered system. This review presents a critical summary of the recent progress of novel materials for MSCs, fabrication methods, advanced design, and challenges in the MSCs industry.

High-Performance Dual-Redox-Mediator Supercapacitors Based on Buckypaper Electrodes and Hydrogel Polymer Electrolytes.

In recent years, the demand for solid, thin, and flexible energy storage devices has surged in modern consumer electronics, which require autonomy and long duration. In this context, hybrid supercapacitors have become strategic, and significant efforts are being made to develop cells with higher energy densities while preserving the power density of conventional supercapacitors. Motivated by these requirements, we report the development of a new high-performance dual-redox-mediator supercapacitor. In this study, cells were constructed using fully moldable buckypapers (BPs), composed of carbon nanotubes and cellulose nanofibers, as electrodes. We evaluated the compatibility of BPs with hydrogel polymer electrolytes, based on 1 mol L-1 H2SO4 and polyvinyl alcohol (PVA), supplemented with different redox species: methylene blue, indigo carmine, and hydroquinone. Solid cells were constructed containing two active redox species to maximize the specific capacity of each electrode. Considering the main results, the dual-redox-mediator supercapacitor exhibits high energy density of 32.0 Wh kg-1 (at 0.8 kW kg-1) and is capable of delivering 25.9 Wh kg-1 at high power demand (4.0 kW kg-1). Stability studies conducted over 10,000 galvanostatic cycles revealed that the PVA polymer matrix benefits the system by inhibiting the crossover of redox species within the cell.

Planar Micro-Supercapacitors with High Power Density Screen-Printed by Aqueous Graphene Conductive Ink.

Simple and scalable production of micro-supercapacitors (MSCs) is crucial to address the energy requirements of miniature electronics. Although significant advancements have been achieved in fabricating MSCs through solution-based printing techniques, the realization of high-performance MSCs remains a challenge. In this paper, graphene-based MSCs with a high power density were prepared through screen printing of aqueous conductive inks with appropriate rheological properties. High electrical conductivity (2.04 × 104 S∙m-1) and low equivalent series resistance (46.7 Ω) benefiting from the dense conductive network consisting of the mesoporous structure formed by graphene with carbon black dispersed as linkers, as well as the narrow finger width and interspace (200 µm) originating from the excellent printability, prompted the fully printed MSCs to deliver high capacitance (9.15 mF∙cm-2), energy density (1.30 µWh∙cm-2) and ultrahigh power density (89.9 mW∙cm-2). Notably, the resulting MSCs can effectively operate at scan rates up to 200 V∙s-1, which surpasses conventional supercapacitors by two orders of magnitude. In addition, the MSCs demonstrate excellent cycling stability (91.6% capacity retention and ~100% Coulombic efficiency after 10,000 cycles) and extraordinary mechanical properties (92.2% capacity retention after 5000 bending cycles), indicating their broad application prospects in flexible wearable/portable electronic systems.

Designing high-performance hybrid supercapacitors and electrochemical sensors with carbon nanotube-embedded silver manganese sulfide@AC@NF composites

Recently, there has been a lot of interest in hybrid supercapacitors due to their amazing capacity to store energy, surpassing the energy storage capability of both conventional supercapacitors and batteries. In this work, physical integration of silver manganese sulphide (AgMnS) into carbon nanotubes was achieved using hydrothermal synthesis. A comprehensive evaluation was conducted on the material's electrical characteristics. With this composite functioning as the positive electrode and activated carbon (AC) acting as the negative, an asymmetric device configuration was used. The AgMnS@CNT composite demonstrated a notable specific capacity of 358.0C/g at a 2.0 A/g rate. The material demonstrated a remarkable 49.5 Wh/kg energy density and a remarkable 1505.0 W/kg power density. 83.3 % of the initial capacity of the composite material remained even after 5000 cycles. This illustrates its continued stability and suggests that its operating lifetime may be increased. Besides; the hybrid electrode is used to detect the glucose in the specimen up to 0 mM to 2 mM. The electrochemical device showed a remarkable value of sensitivity of 1402 μA·cm−2 mM−1. As the field of energy storage technology develops, this dynamic composite may reveal completely new and exciting options.

Enhanced Supercapacitor Performance by Harnessing Carbon Nanoparticles and Colloidal SnO2 Quantum Dots

The creation of effective supercapacitor materials is still a priority in the quest to improve energy storage technology. Herein, we present a novel nanocomposite composed of carbon nanoparticles (CNPs) and colloidal SnO2 quantum dots (c-SQDs) or colloidal SnO2 ultrasmall nanoparticles, synthesized through a facile sonochemical-assisted hydrothermal approach. The XRD and XPS analyses confirmed the successful synthesis and composition of the CNP/c-SQD nanocomposite. Morphology studies revealed a well-dispersed morphology with intimate interfacial interactions between the CNPs and c-SQDs. Specifically, the nanocomposite exhibited a high specific capacitance of 569 F/g at a current density of 1 A/g, surpassing conventional carbon-based supercapacitors. Furthermore, the nanocomposite displayed excellent stability with 99% capacity retention after 5000 cycles, indicative of its superior cyclability. These results underscore the potential of the CNP/c-SQD nanocomposite as a promising electrode material for high-performance supercapacitor applications, offering enhanced charge storage capacity, stability, and cyclability. This study contributes to the advancement of energy storage technologies, paving the way for the development of efficient and sustainable electrochemical energy storage devices.

Ultrafast high-capacitance supercapacitors employing carbons derived from Al-based metal-organic frameworks

Compact supercapacitors (SCs) have garnered significant attention due to their potential to replace bulky aluminum electrolytic capacitors (AECs) in alternating current (AC) line filtering applications. However, the slow response speeds of conventional SCs based on activated carbons are inadequate for such high-frequency applications. Therefore, this paper presents a study on high-frequency SCs using metal-organic framework (MOF)-derived carbon (MDC) electrode materials. Here, the carbonization of the selected MOF results in highly conductive carbons with hierarchical pore structures that offer substantial advantages for use as electrode materials in ultrafast SC applications. Consequently, the as-fabricated MDC SCs exhibit significant areal and volumetric capacitances of 2.41 mF cm–2 and 5.74 F cm–3, respectively, at 120 Hz, coupled with a rapid response speed indicated by a phase angle of –80.1°. Notably, this performance is superior to that of the state-of-the-art high-frequency SCs based on carbon materials. The results underscore the potential of MDCs as electrode materials for use in ultrafast SCs, with eventual implications for the miniaturization of electronic devices.

High-energy density cellulose nanofibre supercapacitors enabled by pseudo-solid water molecules

Compared with conventional electrochemical supercapacitors and lithium-ion batteries, the novel amorphous cellulose nanofibre (ACF) supercapacitor demonstrates superior electric storage capacity with a high-power density, owing to its fast-charging capability and high-voltage performance. This study unveils introduces an ACF supercapacitor characterised by a substantial energy density. This is achieved by integrating a singular layer of pseudo-solid water molecules (electrical resistivity of 1.11 × 108 Ω cm) with cellulose nanofibers (CNFs), establishing forming an electric double layer at the electrode interface. The enhanced energy storage in these high-energy density capacitors (8.55 J/m2) is explicated through the polarisation of protons and lone pair electrons on oxygen atoms during water electrolysis, commencing at 1.23 V. Improvements in energy density are attainable through CNF density enhancements and charging-current optimisation. The proposed ACF supercapacitor offers substantial promise for integration into the power sources of flexible and renewable paper-based electronic devices.

A cleaner lignin-induced 3D porous MXenes hybrid electrode with enlarged voltage and high capacitance retention

Conventional supercapacitors face narrow voltage and an inevitable reduction in capacitance retention during operation, significantly preventing its further commercial application. So, biomass-derived composite materials have attracted intensive attention, especially for pseudocapacitive supercapacitors. Herein, a high-end utilization strategy of lignin to induce a 3D porous layered MXenes/graphene oxide hybrid electrode (LGM2-80) and homologous gel electrolytes with low interface resistance for lignin-derived supercapacitors is demonstrated by a simple hydrothermal method. A more uniform distribution and smaller nanospheres ≈<10 nm of lignin prevent the restacking and increase the interlayer spacing of graphene oxide, also play an adhesive role between graphene oxide and MXene, guaranteeing the maximization of the pseudocapacitance effect between lignin and MXene. Consequently, the LGM2-80 electrode showed a wide operating potential (−0.7∼1.0 V), breaking through the bottleneck of MXene-derived devices with limited working voltage (typically≤0.6 V). Furthermore, the lignin-derived symmetric quasi-solid-state supercapacitor (LGM2-80//lignin gel//LGM2-80) possesses an excellent capacitance retention rate of 149 % at 5,000 cycles, which is far exceeding the current reported supercapacitors. This innovative use of lignin opens up new perspectives for ultra-voltage and ultra-high capacitance retention of advanced supercapacitors.

Boosting Zinc Hybrid Supercapacitor Performance via Thiol Functionalization of Graphene-Based Cathodes.

Zinc hybrid supercapacitors (Zn-HSCs) hold immense potential toward the next-generation energy storage systems, effectively spanning the divide between conventional lithium-ion batteries (LIBs) and supercapacitors. Unfortunately, the energy density of most of Zn-HSCs has not yet rivalled the levels observed in LIBs. The electrochemical performance of aqueous Zn-HSCs can be enhanced through the chemical functionalization of graphene-based cathode materials with thiol moieties as they will be highly suitable for favoring Zn2+ adsorption/desorption. Here, a single-step reaction is employed to synthesize thiol-functionalized reduced graphene oxide (rGOSH), incorporating both oxygen functional groups (OFGs) and thiol functionalities, as demonstrated by X-ray photoelectron spectroscopy (XPS) studies. Electrochemical analysis reveals that rGOSH cathodes exhibit a specific capacitance (540 Fg-1) and specific capacity (139 mAhg-1) at 0.1 Ag-1 as well as long-term stability, with over 92% capacitance retention after 10000 cycles, outperforming chemically reduced graphene oxide (CrGO). Notably, rGOSH electrodes displayed an exceptional maximum energy density of 187.6Whkg-1 and power density of 48.6kWkg-1. Overall, this study offers an unprecedented powerful strategy for the design and optimization of cathode materials, paving the way for efficient and sustainable energy storage solutions to meet the increasing demands of modern energy applications.

Peptide‐Based Assemblies for Supercapacitor Applications

The increased focus on green energy storage devices and the related rapid advancement in biomedical technologies makes the investigation of biocompatible integrated systems with medical relevance increasingly important. Peptides and their assembled morphologies with their innate biocompatibility and biodegradability are emerging as promising candidates in this respect due to their structural attributes which can be easily tuned to form supramolecular 3D architectures with extended pathways for ionic mobility. However, to comprehend their applicability in energy storage devices, it is crucial to explore their self‐assembling characteristics, charge‐storage mechanisms, and coating efficacies. Herein, all these aspects are compiled with specific emphasis on peptide‐based systems for supercapacitor applications. The electrochemical charge storage mechanisms that are used for categorizing conventional supercapacitors with the theories and mechanisms outlining biological electron transfer, such as tunneling, hopping, superexchange, and flickering resonance, are collated. Furthermore, the characterization techniques solely pertaining to the study of such systems and their role in predicting the morphology of self‐assembly patterns which could directly impact the overall electrochemical properties are also addressed. Finally, some of the critical challenges associated with these systems while realizing their future potential in the field of sustainable energy storage devices are highlighted.

Compact aqueous zinc–carbon capacitors with high capacity and ultra-long lifespan

Aqueous zinc–carbon capacitors possess great potential for bridging the gap between conventional batteries and supercapacitors by offering abundant high-power energy.

Freestanding Carbon Nanofibers Derived from Biopolymer (Kraft Lignin) as Ultra-Microporous Electrodes for Supercapacitors

Lignin-derived carbon nanofibers (LCNFs) formed via the solution blowing of a biopolymer are developed here as a promising replacement for polyacrylonitrile (PAN)-derived carbon nanofibers (PCNFs) formed via electrospinning for such applications as supercapacitor (SC) electrodes. Accordingly, it is demonstrated here that a biopolymer (kraft lignin, which is, essentially, a waste material) can substitute a petroleum-derived polymer (PAN). Moreover, this can be achieved using a much faster and safer fiber-forming method. The present work employs the solution blowing of lignin-derived nonwovens and their carbonization to form electrode materials. These materials are characterized and explored as the electrodes in supercapacitor prototypes. Given the porosity importance of carbon fibers in SC applications, N2 gas adsorption tests were performed for characterization. LCNFs revealed the specific surface area (SSA) and capacitance values as high as 1726 m2/g and 11.95 F/g, which are about one-half of those for PCNFs, 3624 m2/g and 25.5 F/g, respectively. The capacitance values of LCNFs are comparable with those reported in the literature, but the SSA observed here is much higher. Moreover, no further post-carbonization activation steps were performed here in comparison with those materials reported in the literature. It was also found here that fiber pre-oxidation in air prior to carbonization and the addition of zinc chloride affect the SSA and capacitance values of both LCNFs and PCNFs. The electrochemical tests of the SCs prototypes were used to evaluate their capacitance at different charging rates, voltage windows, and the number of cycles. The capacitance of PCNFs decreased by about 47% during fast charging, while the capacitance of LCNFs improved during fast charging, bringing them to the level of only 21% below that of PCNFs. These changes were correlated with the packing density of the electrodes. It should be emphasized that LCNFs revealed a much higher mass yield, which was 4–5 times higher than that of PCNFs. LCNFs also possess a higher packing density, a lower price, and cause a significantly lower environmental impact than PCNFs. The best cell supercapacitor delivered a maximum specific energy of 1.77 Wh/kg and a maximum specific power of 156 kW/kg, surpassing conventional electrochemical supercapacitors. Remarkably, it retained 95.2% of its initial capacitance after 10,000 GCD cycles at a current density of 0.25 A/g, indicating robust stability. Accordingly, kraft lignin, a bio-waste material, holds great promise as a raw material for supercapacitor electrodes.

High Energy Density Supercapacitors: An Overview of Efficient Electrode Materials, Electrolytes, Design, and Fabrication.

Supercapacitors (SCs) are potentially trustworthy energy storage devices, therefore getting huge attention from researchers. However, due to limited capacitance and low energy density, there is still scope for improvement. The race to develop novel methods for enhancing their electrochemical characteristics is still going strong, where the goal of improving their energy density to match that of batteries by increasing their specific capacitance and raising their working voltage while maintaining high power capability and cutting the cost of production. In this light, this paper offers a succinct summary of current developments and fresh insights into the construction of SCs with high energy density which might help new researchers in the field of supercapacitor research. From electrolytes, electrodes, and device modification perspectives, novel applicable methodologies were emphasized and explored. When compared to conventional SCs, the special combination of electrode material/composites and electrolytes along with their fabrication design considerably enhances the electrochemical performance and energy density of the SCs. Emphasis is placed on the dynamic and mechanical variables connected to SCs' energy storage process. To point the way toward a positive future for the design of high-energy SCs, the potential and difficulties are finally highlighted. Further, we explore a few important topics for enhancing the energy densities of supercapacitors, as well as some links between major impacting factors. The review also covers the obstacles and prospects in this fascinating subject. This gives a fundamental understanding of supercapacitors as well as a crucial design principle for the next generation of improved supercapacitors being developed for commercial and consumer use.

Methylene blue modified graphene film as high-performance electrode towards all-in-one flexible supercapacitors with “all-graphene” structure

The emergence of wearable electronics has raised the demand for flexible supercapacitors. However, conventional multilayer flexible supercapacitors have high interfacial resistance and unavoidable displacement among adjacent components during the bending process. Herein, a novel all-in-one flexible supercapacitor (AFSC) with “all-graphene” structure is proposed. Benefit from the additional pseudocapacitance enhancement of methylene blue (MB) molecules, the AFSC assembled with the flexible self-supporting MB modified graphene hydrogel film (MB/rGO) obtained by a simple hydrothermal as electrode and graphene oxide (GO) as separator exhibits a high specific capacitance of 317.27 F g−1 at 0.2 A g−1. Even at a high current density of 20 A g−1, the specific capacity still maintains 213.66 F g−1. Besides, the soft package AFSC device shows excellent flexibility, mechanical properties and electrochemical stability. After continuously bending from 0° to 180° for 1200 times, the AFSC device can display a high capacity retention of 90.8%, showing splendid expectation in the field of flexible wearable applications.