Competitive Electrode Materials Research Articles

Redox active cobalt based bi-linker metal organic frameworks derived from 5-sulfoisopthalic acid and 4,4-bipyridine for supercapacitor

In this research study, we have synthesized, characterized and extensively compared the electrochemical characteristics of two materials derived from 5-sulphoisophtalic acid, 4,4-bipyridine and cobalt metal using sonochemical method. Cobalt-bipyridine complex with 5-SIP in lattice structure (RG-41) showed predominant capacitive behavior whereas Co-SIP-Bpy MOF (RG-42) exhibited significant pseudocapacitive attributes due to the presence of coordination linkage responsible for the electron transfer. Due to the effective electrochemical properties of RG-42, we implemented it practically by fabricating a hybrid device with outstanding electrochemical features, demonstrating impressive 92 % cyclic stability with energy density and power density of 51.41 Wh/kg and 800 W/kg at 1 A/g, respectively. Dunn's method was employed to obtain capacitive-diffusive contributions for both half-electrochemical cells as well as hybrid device. These results underscored the potential of RG-42 as a competitive electrode material for future energy storage applications.

Nickel-Copper Bimetallic Oxide Nanoparticles Prepared by Simple Coprecipitation Method as High Performance Electrode Materials for Asymmetric Supercapacitors.

Supercapacitors with transition bimetallic oxides as pseudocapacitive materials have been of wide concern for their excellent energy storage performance. In this work, a simple coprecipitation method was used to synthesize the precursor, followed by calcination to prepare Ni-Cu bimetallic oxide materials. The structure, morphology and properties of the materials prepared by different precipitating agents and different calcination temperatures of NCO-H2C2O4 precursor were investigated. The optimum precipitant was determined to be H2C2O4, and Ni-Cu nanoparticles with regular lamellar microstructure were obtained at the calcination temperature of 400 °C. The nanostructure and morphology provide a large active channel for the rapid diffusion of electrolyte ions, and the specific capacitance of NCO-H2C2O4-400 electrode material can reach 740.31 F/g Cs at 1 A/g. The investigation of charge storage mechanism shows that the contribution rate of capacitance and diffusion control is about 37.9% and 67.2%, respectively. The electrochemical test results of the asymmetric supercapacitors (ASC) constructed with NCO-H2C2O4-400 and activated carbon show that the specific capacitance, energy density, and power density of the capacitor are 52.66 F/g, 16.45 Wh/kg, and 759.51 W/kg, respectively. Even after 5000 charge/discharge cycles at 5 A/g, it can still keep 90.57% of its initial capacity. This work not only provides competitive electrode materials for energy storage devices but also provides a feasible strategy for producing complex transition metal oxide materials with high capacitance performance.

High-Performance Organic-Inorganic Hybrid Conductive Hydrogels for Stretchable Elastic All-Hydrogel Supercapacitors and Flexible Self-Powered Integrated Systems.

Conductive polymer hydrogels exhibit unique electrical, electrochemical, and mechanical properties, making them highly competitive electrode materials for stretchable high-capacity energy storage devices for cutting-edge wearable electronics. However, it remains extremely challenging to simultaneously achieve large mechanical stretchability, high electrical conductivity, and excellent electrochemical properties in conductive polymer hydrogels because introducing soft insulating networks for improving stretchability inevitably deteriorates the connectivity of rigid conductive domain and decreases the conductivity and electrochemical activity. This work proposes a distinct confinement self-assembly and multiple crosslinking strategy to develop a new type of organic-inorganic hybrid conductive hydrogels with biphase interpenetrating cross-linked networks. The hydrogels simultaneously exhibit high conductivity (2000 S m-1), large stretchability (200%), and high electrochemical activity, outperforming existing conductive hydrogels. The inherent mechanisms for the unparalleled comprehensive performances are thoroughly investigated. Elastic all-hydrogel supercapacitors are prepared based on the hydrogels, showing high specific capacitance (212.5 mF cm-2), excellent energy density (18.89 µWh cm-2), and large deformability. Moreover, flexible self-powered luminescent integrated systems are constructed based on the supercapacitors, which can spontaneously shine anytime and anywhere without extra power. This work provides new insights and feasible avenues for developing high-performance stretchable electrode materials and energy storage devices for wearable electronics.

Cellulose nanocrystal-derived carbon electrodes for sustainable potassium-ion charge storage systems

We have here produced carbon electrode materials derived from Crystalline NanoCellulose (CNC) for low-cost potassium-ion based energy storage systems through conventional annealing as well as through a fast and energy efficient microwave assisted carbonization process. A two-step 4-minute synthesis with ZnCl2 activation in a domestic microwave leads to a micro/mesoporous carbon with high surface area (SBET∼1800 m2 g−1). These CNC-derived carbons, if assessed in symmetric supercapacitor C/C cells cycled with 0.5 M K2SO4 aqueous electrolyte, show reversible capacitance values up to 66 F g−1 at current densities of 5 A g−1, retaining 83% of its initial capacitance after 10.000 cycles without any conducting additive. Due to its large electrochemical window of 1.7 V, a competitive energy density for an aqueous system of 20.9 W h kg−1 is achieved. A hybrid aqueous capacitor built with this carbon as negative electrode and coupled with a Prussian White as positive results in cell capacitance values up to 135 F g−1 under a voltage operation window of 1.8 V in 0.5 M K2SO4. On the other hand, non-activated carbons produced through a 2.25 hour thermal annealing at 900 °C, present much lower surface area (SBET∼450 m2 g−1), most of it due to its high micropore volume. This low external and mesoporous surface area carbon is a competitive anode material for potassium-ion batteries with a reversible capacity of ∼200 mA h g−1 cycled at 28 mA g−1 using 3.9 M KFSI in DME electrolyte (favourably most of it below 1 V vs K+/K) in a potassium half-cell with >80% retention in 100 cycles. The present research shows that sustainable CNC derived carbons produced through energy efficient methods are competitive electrode materials in low-cost K based energy storge systems.

2D organic-inorganic supercrystalline structures with 3D layered ion channels for efficient aqueous zinc ion storage

Aqueous zinc ion batteries (AZIBs) have become powerful substitutes for large-scale energy storage because of their high safety and low cost, so the design of high-performance cathode materials has always been a requirement. Layered VxOy is one key type of cathode materials for rechargeable AZBs. Usually, it shows two-dimensional (2D) ion diffusion mechanism through the intercalation/deintercalation of Zn2+ at edge sites, but is plagued by the inert basal planes. Here, polymelamine (PME) was successfully inserted into the layered structure of VO2 nH2O and an organic–inorganic supercrystalline structure (PMVO-sls) with layered structure along the c-axis and ab plane was formed, thus providing additional ion diffusion channels and abundant active sites. The highly efficient and ultrafast 3D Zn2+ intercalation/deintercalation behaviors along both the c-axis and ab plane of VO2 nH2O are realized for the first time in AZIBs. Moreover, PMVO-sls has rich oxygen vacancy (Od) which is beneficial to electrolyte transport and ion diffusion, and it is a very competitive electrode material. Experimental data and density functional theory calculation (DFT) have confirmed that the intercalation of PEM can improve the electronic conductivity of materials and explained the possibility of Zn2+ diffusion through 3D interlayer structural channels. As cathode materials for AZIBs in 3 M Zn (CF3SO3)2, PMVO-sls exhibited an ideal reversible capacity of 344 mA h g−1 at 0.2 A g−1, and excellent cyclic stability (121 mA h g−1 retained after 4,500 cycles at 10 A g−1, a retention rate of 93%). Furthermore, in PMVO-sls/2.8 M Zn (CF3SO3)2 + 0.2 M ZnSO4/Zn AZIBs, PMVO-sls has a higher reversible capacity with an reversible capacity of 392.1 mA h g−1 at 0.2 A g−1 and better cyclic stability (180 mA h g−1 retained after 6,000 cycles at 10 A g−1, a retention rate of 90%). This method can provide a new way for the synthesis of high quality cathode materials for AZIBs and other metal ion batteries.

High-rate electrochimcal supercapacitor with attractive energy density assembling from infused-undaria-pinnatifida-based activated carbon

In order to achieve attractive energy density and specific capacitance of electrochemical supercapacitor, multi-heteroatom self-doped carbon is prepared by pyrolyzing the aquatic biomass undaria pinnatifida (UP) filled with magnesium acetate (Mg(CH3COO)2). The pyrolysis product of magnesium oxide (MgO), acting as rigid filling, can shape the pore and help to keep the original pore system. The resultant immersed-undaria-pinnatifida-based activated carbon (IUPAC-700) co-doped with multi-heteroatom shows specific surface area of 1116 m2 g−1, pore volume of 1.63 cm3 g−1 and desired pore size distribution. The electrode basing on it delivers specific capacitance of 579.7 F g−1 at the current density of 0.50 A g−1 and 306.0 F g−1 at 100.0 A g−1 in the electrolyte of 1.0 M H2SO4. It exhibits a high specific capacitance of 488.6 F g−1 in the two-electrode system and provides a significant energy density of 28.7 W kg−1 at the power density of 164.0 W kg−1. It also displays perfect cyclic life after 8000 times charge-discharge at the current density of 5.0 A g−1. The assembled supercapacitor can power the LED lights. The sample IUPAC-700 featured with self-doped multi-heteroatoms is a very competitive electrode material for energy storage device with desired comprehensive performance.

Kelp derived hierarchically porous carbon aerogels with ultrahigh surface area for high-energy-density supercapacitor in aqueous electrolyte

Nowadays, obtaining porous carbons from abundant and sustainable biomass as electrode materials for energy storage has been attracting tremendous attentions, to meet the requirement of energy consumption and environmental remediation. In this study, hierarchically porous carbon aerogels (HPCAs) with desirable micro-, meso- and macropores were obtained via decoloration, freeze-drying and subsequent carbonizing-activating process using kelp as sustainable, low-cost and massive precursors by adjusting the activation temperature. The effect of temperature on the pore structures and electrochemical performance of HPCAs were investigated in depth. At 800 °C, the as-obtained HPCA-800 had an appropriate combination of specific surface area and hierarchically porous networks, rendering the optimal capability of electrolyte ion's accumulation and transportation. The HPCA-800 exhibited highest specific capacitance of 278 F g−1 in 6 M KOH and 1965 F g−1 and 1 M KOH + 0.06 M K3Fe (CN)6 electrolyte, respectively, which are superior to those of the reported carbon aerogels. Moreover, an ultrahigh energy density of 93 W h kg−1 at high power density of 2109 W kg−1 was achieved in the redox electrolyte. The energy storage mechanism was also elucidated. The HPCAs from kelp should be promising and competitive electrode materials for constructing high-energy-density supercapacitor, owing to their outstanding supercapacitor performance together with the superior advantages of raw materials including abundance, low-cost and renewability.

Facile synthesis of O and P co-doped hierarchical porous carbon nanosheets from biomass for high-performance supercapacitors

Biomass-derived carbons with porous structures and abundant surface functional groups have been regarded as a competitive electrode material for supercapacitors due to their renewability and easily adjustable porosity. The low-cost and environmentally friendly synthesis method of O and P co-doped hierarchical porous carbon nanosheets from waste coconut shells using potassium bicarbonate (KHCO3) and potassium dihydrogen phosphate (KH2PO4) as both activators and co-doped agents have been investigated for high-performance supercapacitors. Under an appropriate KH2PO4 dosage, the pore structure of PAC-0.9 contains micropores, mesopores and macropores, and its specific surface area is 892.06 m2 g−1. The specific capacitance of PAC-0.9 in three electrode system reached 371.63 F g−1 at a current density of 0.5 A g−1, and remained at 223.25 F g−1 even for a current density of 30 A g−1. The symmetrical supercapacitor assembled with PAC-0.9 as the electrode achieved an energy density of 9.15 Wh kg−1 at a power density of 500 W kg−1. At a current density of 5 A g−1, the specific capacitance of PAC-SSC can still retain 96.23 % after 10,000 charge-discharge cycles.

Sphere-shaped CuCo2O4 nanostructures battery type electrode for supercapacitor via hydrothermal synthesis approach

Transition metal oxide (TMO) is expected to be a highly competitive electrode material for energy storage applications based on its superior electrical and theoretical capacity in supercapacitors. However, a larger surface area and higher porosity are required to improve the electrode's electrochemical performance for practical applications. The nanostructured CuCo2O4 nanoparticles was prepared via a simple hydrothermal process with increased surface area and favorable active site to promote electrolyte penetration. The optimal hydrothermal reaction time was investigated to allow nanoparticle overgrowth, which will be critical in determining the specific surface area of the electrode material. The CuCo2O4 prepared at 7 h hydrothermal reaction period, (i.e. CCO-7 h) battery type electrode revealed a capacity of 193 F/g (96.5 C/g) at 3 mA/cm2 and capacity retention of 85.9% over 6000 cycles at 15 mA/cm2. Furthermore, the activated carbon and CCO-7 h (CCO//AC) asymmetric supercapacitor (ASC) exhibited energy and power densities of 2.120 Wh/kg and 277 W/kg, respectively with a capacity retention of 64% after 2000 cycles. The binary metal oxide CuCo2O4 with unique morphology could be a promising battery type electrode for supercapacitor device application.

One-pot synthesis of NiO-MnCo2O4 heterostructure hollow spheres via template-free solvothermal method for high-performance supercapacitors

Supercapacitors employ transitional metal oxides as pseudocapacitive materials have drawn great attention owing to their prominent energy storage performances, but most of them are concentrate on simplex metal oxides. In this work, we reported a novel electrode material for supercapacitors composed of NiO-MnCo2O4 heterostructure hollow spheres via a facile and one-pot route. The resulting hybrid electrode material demonstrates a high specific capacity of 660 C g−1 at 1 A g−1. An assembled hybrid supercapacitor based on this unique heterostructure hollow spheres as positive electrode and nitrogen doped hierarchically porous carbon as negative electrode indicates a favorable energy density of 40 Wh kg−1 at 750 W kg−1 and long cycling lifespan of nearly 90% capacity retention rate after 5000 cycles. This work not only produces a competitive electrode material for energy storage devices but also offers a feasible strategy for producing complex transitional metal oxides materials with high capacitive performance.

Electrochemical Double-Layer Capacitor based on Carbon@ Covalent Organic Framework Aerogels.

High energy demand results in comprehensive research of novel materials for energy sources and storage applications. Covalent organic frameworks (COFs) possess appropriate features such as long-range order, permanent porosity, tunable pore size, and ion diffusion pathways to be competitive electrode materials. Herein, we present a deep electrochemical study of two COF-aerogels shaped into flexible COF-electrodes (ECOFs) by a simple compression method to fabricate an electrochemical double-layer capacitor (EDLC). This energy storage system has considerable interest owing to its high-power density and long cycle life compared with batteries. Our result confirmed the outstanding behavior of ECOFs as EDLC devices with a capacity retention of almost 100 % after 10 000 charge/discharge cycles and, to our knowledge, the highest areal capacitance (9.55 mF cm-2 ) in aqueous electrolytes at higher scan rates (1000 mV s-1 ) for COFs. More importantly, the hierarchical porosity observed in the ECOFs increases ion transport, which permits a fast interface polarization (low τ0 values). The complete sheds light on using ECOFs as novel electrode material to fabricate EDLC devices.

Electrochemical Double‐Layer Capacitor based on Carbon@ Covalent Organic Framework Aerogels

AbstractHigh energy demand results in comprehensive research of novel materials for energy sources and storage applications. Covalent organic frameworks (COFs) possess appropriate features such as long‐range order, permanent porosity, tunable pore size, and ion diffusion pathways to be competitive electrode materials. Herein, we present a deep electrochemical study of two COF‐aerogels shaped into flexible COF‐electrodes (ECOFs) by a simple compression method to fabricate an electrochemical double‐layer capacitor (EDLC). This energy storage system has considerable interest owing to its high‐power density and long cycle life compared with batteries. Our result confirmed the outstanding behavior of ECOFs as EDLC devices with a capacity retention of almost 100 % after 10 000 charge/discharge cycles and, to our knowledge, the highest areal capacitance (9.55 mF cm−2) in aqueous electrolytes at higher scan rates (1000 mV s−1) for COFs. More importantly, the hierarchical porosity observed in the ECOFs increases ion transport, which permits a fast interface polarization (low τ0 values). The complete sheds light on using ECOFs as novel electrode material to fabricate EDLC devices.

Amorphous carbon nanofibers incorporated with ultrafine GeO2 nanoparticles for enhanced lithium storage performance

As a potential anode material with high theoretical specific capacity, the practical application of GeO 2 is largely hindered by huge volume change and low reactivity, Herein, we proposed the engineering of dual amorphous GeO 2 @C nanofibers via facile electrospinning and thermal annealing process. In this design, numerous ultrafine GeO 2 particles are evenly anchored in carbon nanofibers, which could relief the stress in the carbon material during the lithium/delithiation process. Moreover, the low binding energy of Ge-O bond in the dual amorphous GeO 2 /C nanofibers render for convenient charge transfer. As a result, the electrode delivers highly reversible conversion (GeO 2 + 4Li ↔ Ge + 2Li 2 O) and alloying (Ge + 4.4Li ↔ GeLi 4.4 ) reaction. Furthermore, the GeO 2 @C nanofibers with large specific surface area also supply more active sites for pseudocapacitive lithium storage. Benefitting from the typical structure, the dual amorphous GeO 2 @C nanofibers electrode exhibits high reversible capacity of 1053 mAh g −1 at 0.3 A g −1 after 1000 cycle, and superior rate capacity of 476 mAh g −1 at 5 A g −1 . The excellent electrochemical performance endows dual amorphous GeO 2 @C nanofibers competitive electrode material for next-generation lithium-ion batteries. • Dual amorphous GeO 2 @C nanofibers were prepared by a facile and efficient approach. • Dual amorphous GeO 2 @C nanofibers display outstanding lithium storage properties. • Dual amorphous structure benefits for superior lithium storage.

2D and Layered Ti-based Materials for Supercapacitors and Rechargeable Batteries: Synthesis, Properties, and Applications

: Titanium-based two-dimensional (2D) and layered compounds with open and stable crystal structures have attracted increasing attention for energy storage and conversion purposes, e.g., rechargeable alkali-ion batteries and hybrid capacitors, due to their superior rate capability derived from the intercalation-type or pseudocapacitive kinetics. Various strategies, including structure design, conductivity enhancement, surface modification, and electrode engineering, have been implemented to effectively overcome the intrinsic drawbacks while simultaneously maintaining their advantages as promising and competitive electrode materials for advanced energy storage and conversion. Here, we provide a comprehensive overview of the recent progress on Ti-based compound materials for highrate and low-cost electrochemical energy storage applications (mainly on rechargeable batteries and supercapacitors). The energy storage mechanisms, structure-performance relations, and performanceoptimizing strategies in these typical energy storage devices are discussed. Moreover, major challenges and perspectives for future research and industrial application are also illustrated.

Conjugated Porous Polydiaminophenylsulfone-Triazine Polymer-A High-Performance Anode for Li-Ion Batteries.

Organic compounds are promising electrode materials because of their resource sustainability, environmental friendliness, and highly tailorable properties. The porous conjugated polymer shows great potential as an electrode material for its tunable redox nature, conjugated skeleton, and porous structure. Herein, a novel conjugated porous polymer, polydiaminophenylsulfone-triazine, was synthesized by a simple nucleophilic substitution reaction. The conjugated structure and triazine ring can improve the conductivity, charge-transfer efficiency, and physicochemical stability. Also, the porous polymeric framework shows a large specific surface area and high porosity, providing a large contact area with electrolytes and reducing diffusion distance. The polymer demonstrates highly stable cycling performance and good rate capability as an anode for lithium-ion batteries, suggesting a promising strategy to design a competitive electrode material.

Silica‐Confined Activation for Biomass‐Derived Porous Carbon Materials for High‐Performance Supercapacitors

AbstractBiomass‐derived porous carbons have become the most competitive electrode materials for energy storage devices due to their renewable and sustainability properties. However, the obtained porous carbon by direct pyrolysis of biomass generally has a low surface area and poor porosity, limiting its electrochemical performance. Herein, a silica‐confined activation strategy was used to prepare porous carbon with typical biomass microcrystalline cellulose (MCC) as carbon precursor (noted as MCPC). In this approach, the MCC was coated by silica to create a confined condition, in which the in‐situ generated gases of e. g., CO2, H2O, etc. can diffuse into the porous space to active the carbon framework, resulting in large specific surface area and rich mesoporous structure. Moreover, the influences of silica amount and pyrolysis temperature on MCPC was also investigated. As electrode materials, the MCPC showed excellent electrochemical performance with outstanding stability and high specific capacitance, endowing it with high promising for energy storage.

CoSe@N-Doped Carbon Nanotubes as a Potassium-Ion Battery Anode with High Initial Coulombic Efficiency and Superior Capacity Retention.

Potassium-ion batteries (KIBs) have gained significant interest in recent years from the battery research community because potassium is an earth-abundant and redox-active metal, thus having the potential to replace lithium-ion batteries for sustainable energy storage. However, the current development of KIBs is critically challenged by the lack of competitive electrode materials that can reversibly store large amounts of K+ and electrolyte systems that are compatible with the electrode materials. Here, we report that cobalt monochalcogenide (CoSe) nanoparticles confined in N-doped carbon nanotubes (CoSe@NCNTs) can be used as a K+-storing electrode. The CoSe@NCNT composite exhibits a high initial Columbic efficiency (95%), decent capacity (435 mAh g-1 at 0.1 A g-1), and stability (282 mAh g-1 2.0 A g-1 after 500 cycles) in a 1 M KPF6-DME electrolyte with K as the anode over the voltage range from 0.01 to 3.0 V. A full KIB cell consisting of this anode and a Prussian blue cathode also shows excellent electrochemical performance (228 mAh g-1 at 0.5 A g-1 after 200 cycles). We show that the NCNT shell is effective not only in providing high electronic conductivity for fast charge transfer but also in accommodating the volume changes during cycling. We also provide experimental and theoretical evidence that KPF6 in the electrolyte plays a catalytic role in promoting the formation of a polymer-like film on the CoSe surface during the initial activation process, and this amorphous film is of critical importance in preventing the dissolution of polyselenide intermediates into the electrolyte, stabilizing the Co0/K2Se interface, and realizing the reversibility of Co0/K2Se conversion.

Microwave-assisted preparation and improvement mechanism of carbon nanotube@NiMn2O4 core-shell nanocomposite for high performance asymmetric supercapacitors

A carbon nanotube (CNT)@NiMn2O4 core-shell nanocomposite is successfully prepared by a facile microwave-assisted hydrothermal process. The as-obtained nanocomposite exhibits low charge transfer resistance (2.19 Ω), high specific capacitance (up to 915.6 F g−1 measured by charge-discharge at 1 A g−1) and excellent cycling stability (93.0% capacity retention after 5000 cycles at 5 A g−1). It is found that the weaker crystallinity induced by microwave treatment, synergism between CNTs and NiMn2O4 in the core-shell heterostructure and more defects and vacancies in CNTs caused by acidifying pretreatment can all devote to improving the electrochemical performance of the as-obtained nanocomposite. An asymmetric supercapacitor device using the as-obtained CNT@NiMn2O4 as positive electrode is also successfully fabricated, which exhibits the maximum energy density of 36.5 Wh kg−1 at a power density of 800 W kg−1 and outstanding cycling stability with 82.8% retains capacitance after 10000 cycles at 5 A g−1. The excellent performance indicates that as-fabricated CNT@NiMn2O4 is one of the competitive electrode materials for energy storage devices.

Hierarchical porous carbon electrode materials for supercapacitor developed from wheat straw cellulosic foam

Hierarchical porous carbon has become one of the most competitive electrode materials for supercapacitor. The biomass-derived carbon materials are taken for candidate due to their renewability, sustainability, abundance, and low cost. However, the areal capacitance of carbonized biomass needs to be further improved. Herein, we developed a facile and eco-friendly method for the synthesis of porous carbon from agricultural straw, using carbonizing lignocellulose foams and then KOH activation. The obtained biomass foams were controllably carbonized to form all-carbon material for making the electrode for supercapacitor. The results showed that the as-prepared biomass-derived hierarchical porous carbon (BHPC) materials had a high specific surface area of 772 m2 g−1 after KOH activation, and contained the microporous (1.05–1.74 nm) matching with the electrolyte 6 M KOH. The high porosity and the interconnected three-dimensional nanostructure provided efficient migration of the ions in electrolyte, thus the BHPC displayed an outstanding electrochemical performance of supercapacitors. The specific capacitances attained 226.2 F g−1 (specific surface-area capacitance was 29.3 μF cm−2) at a current density of 0.5 A g−1 within a potential window of −1.0 to 0 V in a three-electrode system. This work provides a promising approach to realizing the waste straws into a high-valued energy storage material.

VSe2/carbon-nanotube compound for all solid-state flexible in-plane supercapacitor

Two-dimensional (2D) metallic transition-metal dichalcogenide (MTMD)/carbon-nanotube (CNT) compounds are competitive electrode materials for solid-state flexible in-plane supercapacitors, resulting from the synergistic effect of the large specific surface area of 2D MTMDs and the excellent mechanical properties of the CNT. In this paper, the high-quality VSe2/CNT electrode material is prepared by the one-step chemical vapor deposition (CVD) method. The CVD method offers a facile and safe way to synthesize a pure VSe2/CNT compound. The VSe2 nanosheets are vertically grown on the surface of the CNT cluster. The vertical configuration of the VSe2 nanosheets on the conductive CNT cluster takes full advantage of the large specific surface area of the VSe2 nanosheets to store charges. The ductile and conductive CNT cluster offers good mechanical and electrical connections to the VSe2 nanosheets. The VSe2/CNT compound is applied as the electrode material of a solid-state flexible in-plane supercapacitor which achieves a specific area capacitance of 1854 μF/cm2 and stable cycling stability, ∼7% degradation after 10 000 times of current cycling. The VSe2/CNT also presents a desirable mechanical stability, and ∼ 90% capacitance is retained after bending up to 40°. This work promotes the application of 2D MTMD compounds in the field of energy storage and wearable devices.