Maximum Specific Capacitance Research Articles

Transfiguring energy with an advantageous supercapacitor integrating MoS2/carbon quantum dots bi‐composites into a high‐performance polypyrrole matrix for unprecedented efficiency

AbstractFor the first time, a simple one‐step in situ chemical polymerization technique is used to create a novel molybdenum disulphide/sulphonated carbon quantum dots (CQDs) and polypyrrole (MCP) nanocomposite that is extended for successful use in charge storage supercapacitor (SC) device. By inheriting qualities of excellent electrical conductivity of MoS2, CQDs and improved pseudocapacitive activity of polypyrrole (PPy), the MCP nanocomposite provides a suitable SC electrode material. 0.6 MCP nanocomposited three‐electrode system demonstrates 93.21% retention after 5000 cycles, and a maximum specific capacity of 2253 F/g at 2 mV/s with higher side of energy density as 106.06 Wh/kg along with a considerable power density as 180.28 W/kg. Using MCP as anode and an AC or activated charcoal electrode as cathode, a solid‐state asymmetric supercapacitor (ASC) was constructed. The fabricated device supplies a greater value of specific capacitance as 154.09 F/g at 100 mV/s and 175 F/g at 0.1 A/g, also evidenced superior energy density data as 126 Wh/kg along with an appreciable power density of 604.8 W/kg. After charging the ASC for 2 min, the light emitting diode shone for 5 min. The findings underpin that MCP is a potential electrode material that could be utilized as a better alternative in futuristic supercapacitor devices.

Facile fabrication of 3D-α-Fe2O3@2D-g-C3N4 heterojunction composite materials: Effect of iron oxide loading on the electrochemical performance

Designing heterojunction nanocomposites is crucial for optimizing supercapacitor electrodes. This study addresses the challenge by introducing a facile synthesis method for creating 3D-α-Fe2O3@2D-g-C3N4 heterojunctions through a bulk carbon nitride-assisted hydrothermal process. During this process, the growth of ferric oxide particles coincides with the exfoliation and deposition of carbon nitride, leading to simultaneous structural changes in both iron oxide and carbon nitride phases. The resulting composite's properties strongly correlate with the iron oxide loading. Comprehensive characterization using XRD, FTIR, SEM-EDAX, XPS and TEM identified three distinct structures for α-Fe2O3/g-C3N4 composites based on iron oxide loading: low, medium, and high. The medium-loaded sample demonstrated superior electrochemical performance, attributed to better interfacial contact and the formation of 3D-Fe2O3@2D-g-C3N4 heterojunctions. This composite, with an optimized 22 wt% iron oxide loading, exhibited a maximum specific capacitance of 925.1 Fg−1 at 5 mVs−1 and 498.6 Fg−1 at 6 Ag−1 in charge-discharge analysis, with stable performance over 2000 cycles. Overall, this research presents an enhanced hydrothermal method for facile preparation of effective α-Fe2O3/g-C3N4 heterojunction materials.

Home-made chemical vapor deposition-based synthesis of binder-free nanostructured magnesium-molybdenum-sulfide electrode materials for supercapacitor application

Molybdenum disulfides (MoS2) is considered as promising electrode materials (E-M) for high electrochemical performance (ECP) of lithium-ion batteries and supercapacitors due to their layered nanostructures. Herein, MoS2, MgS and hetrostructure MgS/MoS2 E-Ms comprising of nano-particles/sheets/needles like structures are synthesized on Nickel foam (Ni–F) by a simple home-made chemical vapor deposition (CVD) technique. The XRD analysis confirmed the formation of MoS2, MgS and MgS/MoS2 polycrystalline E-Ms growing along different directions. The FESEM analysis is confirmed that the addition of MgS layer over the surface of MoS2 change the surafce morphology from nano-particles to nano-needles. The change in structural and microstructural features is indicated the appearance of defects, micro-strain and dislocations density which are fruitful for excellent ECP. The cyclic voltammetry analysis is indicated the pseudocapacitive nature of the synthesized E-Ms. The maximum specific capacitance values for MoS2/Ni–F, MgS/Ni–F and MgS/MoS2/Ni–F E-Ms are 1273, 1688 and 3934 F/g at 1 A/g respectively. Moreover, the addition of MgS layer over MoS2/Ni–F is revealed the excellent cyclic stability of 98.76 % at current density of 10 A/g after 4000 cycles, energy density values are ranged from 79 to 136 W h/kg with homologous power density of 250–2500 W/kg and very small charge transfer resistance. The simulations of Power's Law and Dunn's model is confirmed that the excellent ECP is due to both capacitive and diffusive controlled contributions of heterostructured MgS/MoS2/Ni–F E-Ms. Additionally, MgS/MoS2/Ni–F E-Ms have both battery and pseudocapacitive nature due to unique nano-needles like morphology. The excellent electrochemical properties of MgS/MoS2/Ni–F E-Ms substantiate their potential applications in portable energy storage devices.

Nickel-cobalt-chromium ternary transition metal hydroxide for supercapacitors

Metal hydroxide is a promising electrode material for supercapacitors. And third metal introduction can improve its electrochemical performance. In this paper, the Cr was introducing into NiCo-LDH by one-step hydrothermal method. In addition, the influence of Cr content on the electrochemical performance was investigated. The results show that maximum specific capacitance of 2712 F g−1 with the ratio of Ni: Co: Cr of 1:1:0.05, higher than pure NiCo-LDH of 1676 F g−1. In addition, the assembled NiCoCr-0.05//YP50 supercapacitor devices can reach an energy density of 27.38 Wh kg−1 with a good cycle life.

Effect of doped heteroatom on monolayer SnSe2 adsorption of Na

Based on the first principles, we have calculated the influence of B, Br, and N atom doping on the adsorption properties and optoelectronic properties of monolayer SnSe2 adsorbed Na. The calculations show that vacancy is the most favorable adsorption site for the Na atom. Among the three doping systems, the B-doped system has the best adsorption energy and height and Na’s adsorption capacity. After the adsorption of the Na atom by intrinsic SnSe2, the system behaves from a semiconductor to a metal nature. Doping Br atom increases the adsorption system’s Fermi energy level, the conduction band’s overall energy increases and the electrical conductivity is enhanced. Doping B and N atoms change the adsorption system from metallic to p-type semiconductor properties. The system’s adsorption performance, electrical conductivity, and energy band tunability are improved. Due to the electrostatic repulsion between Na atoms, the adsorption energy of the system shows an increasing trend with the increase in the number of adsorbed Na atoms on the surface. The maximum specific capacity of the surface of the doped system is 373 mAhg−1, and the system has high storage capacity. Optical property calculations show that the static refractive index of the Br-doped adsorption system is maximum. The static refractive index of the doped adsorption system is minimal. Doping makes the system’s energy loss smaller, complex conductivity decreases, intermolecular interactions decrease, and the adsorption system becomes more stable.

Synthesis and characterization of ZnCo2O4 nanocomposites with enhanced electrochemical features for supercapacitor applications

Supercapacitors have recently emerged as a promising alternative to conventional batteries due to their improved energy storage capabilities. The optical, electrochemical, and structural properties of ZnCo2O4 nanocomposites produced by hydrothermal synthesis are detailed in this study. In order to study the physicochemical properties of the synthesized goods, the created nanocomposite samples were analyzed using XRD, FT-IR, UV–Vis, SEM with EDAX, HR-TEM, BET, XPS, and charge storage potential. Crystallite size was found to be inversely proportional to increasing range of 5.01 nm to 10.62 nm in the XRD data, which compared the cubic structure. Electron microscopy and high-resolution transmission electron microscopy (HR-TEM) indicated a morphological shift indicative of improved electrochemical capabilities. The absorption research showed that different molar ratios were successful in increasing the optical bandgap from zero to 1.93 eV, whereas functional component adsorption lowered it from 2.35 eV. A maximum specific capacitance of 383.3 Fg−1 was determined by the electrochemical research, which indicated an inherent pseudo capacitance. Experimental results show that the ZnCo2O4 nanocomposite can effectively store charges, which is in line with expectations given its high capacitance and very inexpensive production.

Iodine intercalation-assisted alkali activation constructs coal-based porous carbon for high-performance supercapacitors

Supercapacitors have the advantages of fast charging and discharging speeds, high power density, long cycle life, and wide operating temperature range. They are widely used in portable electronic equipment, rail transit, industry, military, aerospace, and other fields. The design and preparation of low-cost, high-performance electrode materials still pose a bottleneck that hinders the development of supercapacitors. In this paper, coal was used as the raw material, and the coal-based porous carbon electrode material was constructed using the iodine intercalation-assisted activation method and used for supercapacitors. The CK-700 electrode exhibits excellent charge storage performance in a 6 M potassium hydroxide (KOH) electrolyte, with a maximum specific capacitance of 350 F/g at a current density of 0.5 A/g. In addition, it has an excellent rate performance (310 F/g at 1 A/g) and cycle stability (capacitance retention up to 91.7 % after 30000 cycles). This work provides a method for realizing high-quality, high-yield and low-cost preparation of coal-based porous carbon, and an idea for improving the performance of supercapacitors.

Effect of electrolytes on supercapacitive behavior of cubic shaped pristine cuprous oxide synthesized via sol-gel approach

The present study uses the sol-gel approach to employ cuprous oxide (Cu2O) as an electrode material for the electrochemical energy storage application. Scanning electron microscopy (SEM) examines the structural and surface morphological characteristics of the synthesized material, and pure phase development is verified by the X-ray Diffraction (XRD) patterns. The synthesized material has a high value of specific capacitance, notable porosity, and a well-defined cubic shape. In the three-electrode set-up, the electrochemical analysis uses different aqueous electrolytes, i.e., KOH and NaOH. The electrochemical outcomes indicate that the synthesized material has a maximum specific capacitance (Cs) of 362.77 Fg-1 with excellent stability (104 %) in 6 M NaOH than KOH electrolyte (225 Fg-1). EIS data for Cu2O-based electrodes have been modeled using various equivalent circuits. The ESR value of Cu2O in NaOH electrolyte is much smaller (0.503 Ω) than in KOH electrolyte, indicating the creation of more active sites and enhanced accessibility of ions. Capacitive and diffusion current contributions are shown by using the Trassati and Dunn techniques. Thus, all our findings suggest that sol-gel synthesized pristine cuprous oxide is a potential option for energy storage gadgets.

One pot synthesis of nanostructured bismuth fluoride tailored for symmetric supercapacitor performance

Organic molecule stabilized face-centered cubic structured bismuth fluoride (BiF3) nanoparticles (NPs), space group: Fm-3 m, were prepared using a wet chemical synthesis route for symmetric supercapacitor application. For freestanding three electrode system, at current density (Cd) 3.3 A.g−1, the material displayed a maximum specific capacitance (SCp) value 717.3 F.g−1. The symmetric device based on BiF3 attained a maximum specific capacity (SC) value of 228.4 mAh.g−1 at 0.06 A.g−1. At the current density of 0.30 A.g−1, the device displayed the energy density (Ed) and power density (Pd) values of 0.17 Wh.kg−1 and 343.7 W.kg−1, respectively. Furthermore, the fabricated symmetric supercapacitor displayed 90% of capacity retention and 95% of coulombic efficiency at 0.12 A.g−1 for 1000 galvanostatic charge–discharge (GCD) cycles. The symmetric supercapacitor based on BiF3 NPs exhibited excellent electrochemical performance, which could be an appropriate choice for application in different integrated energy storage systems.

Cycling Stability of a 2D Pristine MOF Supercapacitors

AbstractTwo‐dimensional (2D) metal–organic frameworks (MOFs) have been a worldwide research interest due to their potential application in supercapacitors. Herein, a cobalt‐based layered MOF ([Co2(μ‐SO4)(Hppza)2(H2O)3]n, namely, SEU‐1; H2ppza=3‐(pyridin‐4‐yl)‐1H‐pyrazole‐5‐carboxylic acid) has been synthesized via a one‐step solvothermal method. Single X‐ray diffraction analysis shows that the SEU‐1 exhibits a (3,3,4)‐connected 2D structure with a Schläfli symbol of (62 ⋅ 8)(63)(64 ⋅ 8 ⋅ 10). Variable‐temperature magnetic susceptibility data display that antiferromagnetic interactions between two CoII ions exist in SEU‐1. The supercapacitive performance has been evaluated in the three‐electrode system. Its maximum specific capacitance is 145.5 F g−1 at 1 A g−1, along with the specific capacitance retention of 92.7 % at the current density of 5 A g−1 after 6000 cycles in 3 M KOH solution. These results demonstrate that SEU‐1 is a good candidate for electrode material for electrochemical energy storage.

Sustainable synthesis of spongy-like porous carbon for supercapacitive energy storage systems towards pollution control.

In this study, the fruit of Terminalia chebula, commonly known as chebulic myrobalan, is used as the precursor for carbon for its application in supercapacitors. The Terminalia chebula biomass-derived sponge-like porous carbon (TC-SPC) is synthesized using a facile and economical method of pyrolysis. TC-SPC thus obtained is subjected to XRD, FESEM, TEM, HRTEM, XPS, Raman spectroscopy, ATR-FTIR, and nitrogen adsorption-desorption analyses for their structural and chemical composition. The examination revealed that TC-SPC has a crystalline nature and a mesoporous and microporous structure accompanied by a disordered carbon framework that is doped with heteroatoms such as nitrogen and sulfur. Electrochemical studies are performed on TC-SPC using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. TC-SPC contributed a maximum specific capacitance of 145 F g-1 obtained at 1 A g-1. The cyclic stability of TC-SPC is significant with 10,000 cycles, maintaining the capacitance retention value of 96%. The results demonstrated that by turning the fruit of Terminalia chebula into an opulent product, a supercapacitor, TC-SPC generated from biomass has proven to be a potential candidate for energy storage application.

Carbon nanospheres-induced enhanced capacitive dynamics in C/WS2/WO3 nanocomposites for high-performance electrochemical capacitors

This work investigates the impact of carbon nanospheres on the electrochemical performance of C/WS2/WO3 nanocomposites for electrochemical supercapacitors. The nanocomposites have been synthesized and characterized by various techniques like XRD, UV–vis spectroscopy, SEM, TEM and FTIR. The electrochemical properties of the nanocomposites have been analysed in order to study the charge transport, reaction kinetics, impedimetric properties and specific capacitance by using cyclic voltammetry (CV) and potentio electrochemical impedance spectroscopy (PEIS). The capacitive performance of the samples has been investigated by the obtained specific capacitance values and Nyquist plots. The specific capacitance of the samples has been found in a range of 0.8–2.8F/g at 20 mV/s. The sample with the least amount of carbon showed maximum specific capacitance. The electrochemical insights, combined with comprehensive material characterizations, provide valuable knowledge for tailoring the capacitive performance of C/WS2/WO3 nanocomposites through controlled carbon nanospheres and thus the suitability of materials for electrochemical capacitors.

Side chain-engineered pseudocapacitive semiconducting polymer electrodes for symmetrical supercapacitors operable at wide potentials

Pseudocapacitive electrodes based on inorganic metal oxides exhibit superior capacitance. However, they suffer from limited operational voltage, resulting in low energy and power densities. To address these issues, redox semiconducting polymer (SP)-based pseudocapacitive electrodes, integrating electron donor and acceptor functionalities, offer a promising solution. In this study, we introduce two novel pseudocapacitive SP electrodes composed of highly planar electron-donating building blocks 4,8-bis ((5-octylthiophen-2-yl)ethynyl)benzo[1,2-b:4,5-b'] dithiophene (TBDT) with an electron-accepting building blocks benzo[c][1,2,5]thiadiazole (BT) and its side chain manipulated counterpart, i.e., OBT, denoted as SP1 and SP2, respectively. Among them, SP2 demonstrates a maximum specific capacitance of 117 F/g at 1 A/g. Furthermore, a symmetric supercapacitor fabricated for full-cell applications exhibits a significant energy density, reaching 29.1 Wh kg−1, and a maximum power density of 12.4 kW kg−1 within the wide operating potential window of 2.5 V. The exceptional performance of the pseudocapacitive electrode can be attributed to its highly planar backbone, nanoporous morphology, low crystallinity, and low lowest unoccupied molecular orbital levels. Overall, this new class of pseudocapacitive polymer electrode holds great potential for diverse sustainable energy storage technologies, addressing the limitations of traditional inorganic metal oxide-based electrodes by offering wide potentials window.

Development and comparison of multi-walled carbon nanotubes and graphite nanoflakes dispersed solar salt: Structural formation and thermophysical properties

A molten salt energy storage has proven to be a promising candidate for medium and high-temperature thermal energy storage (TES) applications. Improving the thermophysical properties, such as specific heat capacity (Cp) and thermal conductivity (k) is crucial to deciding the charging/discharging characteristics of the energy storage system. In this study, 1 wt% of two variant carbon allotropes, such as multi-walled carbon nanotubes (MWCNTs) and graphite nanoflakes (GNFs), were dispersed in solar salt (i.e., MWCNTs nanosalt and GNFs nanosalt) using wet preparation method. Thermophysical properties of the prepared nanosalts were evaluated using different analytical techniques and compared with pristine solar salt. The specific heat capacity was measured from 50 °C to 350 °C, and the maximum specific heat capacity enhancement in 1 wt% of MWCNTs dispersed solar salt was 18 %. The enhancement in 1 wt% of GNFs dispersed solar salt was 12.5 % at 200 °C (in solid phase). Similarly, in the liquid phase (at 350 °C), MWCNTs dispersed solar salt improves Cp by 6.2 %, while GNFs dispersed solar salt exhibits negligible improvement in Cp. Further, a modified transient plane source (MTPS) technique was used to measure the thermal conductivity of both carbon nanosalts in the solid phase (30–100 °C). The maximum thermal conductivity enhancement observed for MWCNTs dispersed solar salt and GNFs dispersed solar salt was 5.8 % and 11.7 %. Finally, thermogravimetric analysis was conducted to evaluate the thermal stability of the MWCNTs nanosalt and GNFs nanosalt at a maximum temperature of 700 °C, and found that the MWCNTs nanosalt show better thermal stability than the GNFs nanosalt.

A High-Performance Supercapacitor Based on Hierarchical Template-Free Ni/SnO2 Nanostructures via Hydrothermal Method.

Novel flake-like Ni1-xSnxO2 particles were successfully prepared by template-free hydrothermal synthesis. The prepared samples were investigated for their properties by different characterization techniques. Scanning micrographs showed that the obtained particles consisted of nanoflakes. The X-ray diffraction results of the Ni1-xSnxO2 revealed the formation of mixed-phase Ni/SnO2 having the typical tetragonal structure of SnO2, and the cubic structure of Ni in a nanocrystalline nature. The doping with Ni had a certain influence on the host's lattice structure of SnO2 at different doping concentrations. Confirmation of the functional groups and the elements in the nanomaterials was accomplished using FTIR and EDS analyses. The electrochemical performance analysis of the prepared nanomaterials were carried out with the help of the CV, GCD, and EIS techniques. The specific capacitance of the synthesized nanomaterials with different concentrations of Ni dopant in SnO2 was analyzed at different scanning rates. Interestingly, a 5% Ni-doped SnO2 nanocomposite exhibited a maximum specific capacitance of 841.85 F g-1 at 5 mV s-1 in a 6 M KOH electrolyte. Further, to boost the electrochemical performance, a redox additive electrolyte was utilized, which exhibited a maximum specific capacitance of 2130.33 at 5 mV s-1 and an excellent capacitance retention of 93.22% after 10,000 GCD cycles. These excellent electrochemical characteristics suggest that the Ni/SnO2 nanocomposite could be utilized as an electrode material for high-performance supercapacitors.

Asymmetric supercapacitors based on biomass-derived porous activated carbon (PAC)/1D manganese oxide (MnO2) electrodes with high power and energy densities

In this study, we present the electrochemical performance of an asymmetric supercapacitor (ASC) composed of one-dimensional manganese oxide (MnO2) nanorods embedded in porous activated carbon sheets (MnO2/PAC) as the positive electrode (positrode), and renewable porous activated carbon (PAC) as the negative electrode (negatrode). This configuration facilitates a high rate of charge/discharge while maintaining substantial specific capacity. The MnO2/PAC composite was successfully synthesized using a hydrothermal technique, while the PAC material was produced through pyrolysis reaction. The MnO2/PAC composite exhibited a maximum specific capacitance of 208.75F g−1 at 0.5 A/g and demonstrated a cyclic stability of 87.43 % in neutral aqueous electrolytes. This notable electrochemical performance is attributed to the significant contribution of the high pseudo-capacitance offered by dense MnO2 nanorods, in addition to the expansive surface area of the activated carbon sheets with closely packed structures. The ASC constructed as PAC//MnO2/PAC displayed a high energy density of 23.3 Wh kg−1 and a power density of 350.4 W kg−1 at a current density of 0.5 A/g. Furthermore, the device showcased exceptional cycling stability, retaining 90.3 % at a current density of 4 A/g. These results underscore the substantial untapped potential of ASC devices for innovative applications in advanced energy storage.

Alternative inner filling and outer surface coating of BNNT by Tungsten(VI) oxide for supercapacitor electrode

The motivation behind this research is to address the need for advanced energy storage materials by exploring the selective filling and coating of boron nitride nanotube (BNNT) with tungsten(VI) oxide (WO3) to enhance the pseudocapacitive performance. In this study, we present a novel synthesis method that allows precise control over the extent of filling and coating, aiming to create tailored hybrid structures. Morphological and structural analysis confirm the filling and coating of BNNT by WO3. Inner filling and outer surface coating of BNNT by WO3 significantly impact on the electrochemical properties. The filling of WO3 within the BNNT can enhance the stability of the system, whereas outer surface coating of BNNT by WO3 improves the capacitive performances. The role of BNNT influences both these phenomena by acting as electrolyte transportation channel as well as stabilizing the WO3. In three electrode study, WO3 coated BNNT showed the maximum specific capacitance of 856 F/g at 1 A/g. An asymmetric supercapacitor device using WO3 coated BNNT as positive electrode revealed the maximum specific capacitance of 137 F/g at 2 A/g current density with an improved energy density of 52 W h/kg. The WO3 coated BNNT-based asymmetric supercapacitor device also showed ∼81 % specific capacitance retention after the completion of 10,000 GCD cycles, whereas WO3 filled BNNT-based supercapacitor device demonstrated better stability (∼94 % specific capacitance retention) due to the filling and stabilization of pseudocapacitive WO3 by BNNT.

Ternary nanocomposite of RAFT‐polymerized DMAEMA‐functionalized graphene oxide, manganese dioxide and polyaniline as active electrode material for supercapacitor

AbstractGraphene and its derivatives are promising energy storage devices due to their high specific surface area, chemical and thermal durability and high charge transfer power. Still, their stacking and aggregate behavior can limit their practical application. To address this issue, reversible addition–fragmentation chain‐transfer (RAFT) polymerization as controlled radical polymerization was applied to functionalize the surface of graphene oxide with poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA) via the ‘grafting from’ method. This strategy enhances the distance between graphene sheets by occupying physical volume while improving effective charge transfer through tertiary amine groups participating in the doping process. X‐ray diffraction was used to determine interlayer spacing after polymer grafting, which increased from 0.28 to 1.71 nm after polymer grafting. The hybridization of materials with diverse properties was used to enhance charge transfer capability for supercapacitor applications. PDMAEMA‐functionalized graphene oxide, nano‐manganese dioxide and polyaniline were combined to create a successful nanocomposite as electrode active material. The morphological structure and chemical composition of the synthesized nanocomposite were analyzed, and its electrochemical performance was evaluated using cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. The nanocomposite exhibited a maximum specific capacitance, energy density and power density of 364.72 F g−1 (at a scan rate of 50 mV s−1), 239.08 Wh kg−1 and 678.34 W kg−1, respectively. The final nanocomposite's energy storage capacity significantly increased compared to the individual components due to hybridization's synergistic impact, reducing charge transfer resistance. © 2024 Society of Industrial Chemistry.

Polyaniline nanoarrays grown on holey graphene constructed by frozen interfacial polymerization as binder−free and flexible gel electrode for high−performance supercapacitor

Compared with disordered structures, electrode materials with nanoarray structures can effectively improve the energy storage capacity of supercapacitors. Therefore, the construction of nanoarrays structures is an important research direction. Here, one kind of frozen interfacial polymerization was used to create a polyaniline (PANI) nanoarrays grown on holey graphene (HG). Long polyaniline nanoarrays were constructed with the promotion of ice crystal growth and the abundant pores of the HG. It is demonstrated that the formation of PANI array and hierarchical nanofiber structures is not only conducive to shorten charge transport, but also can effectively alleviate interfacial side reactions. Moreover, benefiting from the abundant active sites and hierarchical porous structure of the HG, highly oriented growth of PANI arrays, efficient charge diffusion and electrolyte infiltration can be achieved. As a result, specific capacitance, reversibility and cycling stability could be significantly improved. Especially, the PANI/HG−10 exhibited the maximum specific capacitance of 793.7 F g−1 at a current density of 1 A g−1. The all−solid−state flexible symmetric supercapacitor assembled by gel electrode possesses the energy density of 32.5 Wh kg–1 at a power density of 326.5 W kg–1, and maintained an excellent cycle retention approaching 90.5 % after 5000 cycles. This work expands the ideas for array structure construction and electrode fabrication.

Bottom-Up Synthesis of Twisted Porous Graphene through a Heterogeneous Scholl Reaction and Its Supercapacitor Application.

Anthracene- and pyrene-based twisted porous graphene (AN-Pyre-PG) with an ordered pore structure has been synthesized through bottom-up solution phase synthesis from a conjugated microporous polymer (AN-Pyre-CMP) via a heterogeneous Scholl cyclization reaction. The regular-ordered pores embedded within the graphene structures were analyzed through a Raman spectrum, different morphological analyses, and theoretical studies. A significant change in surface area from AN-Pyre-CMP to AN-Pyre-PG was observed, from 143 to 640 m2/g, respectively. Surface area-driven capacitive properties were also observed. Twisted-structure and ordered porous graphene shows better specific capacitance compared to CMP. AN-Pyre-PG shows a specific capacitance of 629 F g-1 at 1 A g-1, with 91% retention of capacitance after 3000 charge-discharge cycles, whereas AN-Pyre-CMP shows a maximum specific capacitance of 200 F g-1 was observed at 2 A g-1.