Excellent Capacitive Performance Research Articles

Excellent capacitive storage performance of N-doped porous carbon derived from the orientation-guidance coupled with in-situ activation methodology

The orientation-guidance coupled with in-situ activation methodology is developed to synthesize the N-doped porous carbon (NPC) with well-developed porosity and high specific surface area, using coal pitch as a carbon precursor. The orientation-guidance and activation are dedicated to generating microporous and mesoporous channels, respectively. The in-situ N incorporation into the carbon skeleton is realized along with the formation of porous carbon (PC), ensuring the uniformity of N doping. As an electrode material of supercapacitor, benefiting from the robust hexagon-like building block decorated with micro-mesoporous channels and N doping, NPC electrode affords a significant improvement in capacitive energy-storage performance, achieving a specific capacitance of up to 333F g−1 at 1 A/g, which far exceeds those of PC and activated carbon. Notably, even under high mass loading of 10 mg cm−2, the NPC maintains a satisfactory capacitance of 258F g−1 at 1 A/g. When employed as the anode in Li-ion capacitor (LIC), apart from exhibiting enhanced anode behavior compared to graphite anode, NPC also delivers exceptional cyclability. Furthermore, density functional theory calculations have validated the enhanced electrical conductivity and Li storage ability contributed by N doping, providing a theoretical foundation for the observed improvements in electrochemical performance. A full LIC configured with NPC anode delivers extraordinary Ragone performance and outstanding cyclability. This work also proposes a feasible way to realize the oriented conversion of coal pitch into high-performance electrode materials for electrochemical energy-storage devices.

In Situ Self-Assembly of Nitrogen-Doped 3D Flower-like Hierarchical Porous Carbon and Its Application for Supercapacitors.

The hierarchical porous carbon-based materials derived from biomass are beneficial for the enhancement of electrochemical performances in supercapacitors. Herein, we report the fabrication of nitrogen-doped 3D flower-like hierarchical porous carbon (NPC) assembled by nanosheets using a mixture of urea, ZnCl2, and starch via a low-temperature hydrothermal reaction and high-temperature carbonization process. As a consequence, the optimized mass ratio for the mixture is 2:2:2 and the temperature is 700 °C. The NPC structures are capable of electron transport and ion diffusion owing to their high specific surface area (1498.4 m2 g-1) and rich heteroatoms. Thereby, the resultant NPC electrodes display excellent capacitive performance, with a high specific capacitance of 249.7 F g-1 at 1.0 A g-1 and good cycling stability. Remarkably, this implies a superior energy density of 42.98 Wh kg-1 with a power density of 7500 W kg-1 in organic electrolyte for the symmetrical supercapacitor. This result verifies the good performance of as-synthesized carbon materials in capacitive energy storage applications, which is inseparable from the hierarchical porous features of the materials.

High-temperature dielectric with excellent capacitive performance enabled by rationally designed traps in blends

Polymer dielectrics with excellent capacitive performance are urgently needed in advanced electrical and electronic systems. However, due to the dramatic increase in the conduction loss, the energy density and efficiency of polymers degrade severely at elevated temperatures, limiting their application in harsh environments up to 150 °C. Herein, an all-organic polyurea (PU)/polyetherimide (PEI) blend film is designed to prepare high-temperature polymer dielectric. It is found that carrier traps can be introduced by blending, and the hydrogen bond between PU and PEI increases the trap depth, leading to suppressed leakage current and enhanced breakdown strength, thus improving the energy storage performance. PU/30%PEI exhibits a high discharged energy density of ∼3.74 J/cm3 with an efficiency higher than 90% at 150 °C, which is 78% and 70% higher than pristine PU and PEI, respectively. This work provides a facile strategy to improve the energy storage performance of polymer dielectrics by introducing deep traps through blending.

In Situ Growth 3D GDY-NCNTs Nanocomposites for High-Performance Supercapacitors.

New binary carbon composites (GDY-NCNTs and GDY-CNTs) with a three-dimensional porous structure, which are synthesized by an in situ growth method, are adopted in this article. The GDY-NCNTs composites exhibit excellent specific capacitance performance (679 F g-1, 2 mV s-1, 139% increase compared to GDY-CNTs) and good cycling stability (with a capacity retention rate of up to 116% after 10000 cycles). The three-dimensional porous structure not only promotes ion transfer and increases the effective specific surface area to improve its specific capacitance performance but also adapts to the volume expansion and contraction during the charging and discharging process to improve its cycling stability. The presence of nitrogen doping in the carbon nanotubes of GDY-NCNTs increases the surface defects of the composites, provides more electrochemical points, and improves the surface wettability of the composites, further improving the electrochemical performance of the composites.

Unveiling the dual tunability of dimension and pore structure in MAX-derived carbon via molten salt electrolysis

3D construction or pore-forming of carbon nanosheets brings the materials exceptional energy storage performance. However, these strategies involve complicated procedures and challenging conditions. Herein, based on the structural regulation of a MAX phase, a facile method was proposed to prepare MAX-derived carbon (MDC) with dual tunability of dimension and pore structure via molten salt electrochemical etching-gaseous sulfur delamination coupling. Polyhedral structure Ti2SC and highly oriented structure Ti2SC were transformed into 3D Mesopore carbon nanoshells (3D Meso-CNSL) and 2D Mesopore carbon nanosheets (2D Meso-CNST) in one step. By matching the decomposition voltage of TiClx with that of PS-Ti2SC, Cl2 gas generated in situ was employed to enhance the porosity of the 3D Meso-CNSL, resulting in the formation of 3D meso/macro-porous carbon nanoshells (3D Meso/Macro-CNSL) with doubled pore volume (1.45 cm3 g−1) and specific surface area (649.97 m2 g−1). The 3D Meso/Macro-CNSL exhibits excellent capacity performance and cycle stability under high current density. The capacities are 674.8 mAh g−1 and 501.5 mAh g−1 after 1000 cycles at 5 A g−1 and 10 A g−1, respectively. It is the first report on the direct delamination of MAX phases into 3D nanomaterials, presenting a new pathway for the precise regulation of the nanostructure of the MDCs.

One-pot synthesis of phosphorous, iodine atoms co-functionalized graphene for high-performance supercapacitor and flame-retardant applications

There has been extensive research on heteroatom-doped graphene for electrochemical energy storage and flame-retardant (FR) applications. Herein, we used a one-pot method for developing phosphorous, iodine co-doped reduced graphene oxide (PI@rGO) from red phosphorus and iodine via in situ graphene oxide (GO) reduction for supercapacitor and FR applications. In a symmetrical two-electrode cell device, the as-prepared PI@rGO demonstrated good super capacitive performance of 178 F g−1 at a current density of 1.0 A g−1, along with an exceptional energy density of 20 Wh kg−1 and power density of 1791 W kg−1. The as-synthesized PI@rGO demonstrated outstanding cyclic stability at a high current density of 10 A g−1, retaining up to 84 % of its initial capacitance after more than 6000 recurrent charge–discharge cycles. The synthesized PI@rGO showed excellent FR properties toward cotton fabric and sustained cotton fabric up to 337 s with continuous flame exposure. The control cotton fabric was completely burned in 16 s. The synthesized PI@rGO coated cotton fabric showed an excellent value of 39 % limiting oxygen index and residual char length of 2 cm. With the excellent super capacitive performance and FR properties, PI@rGO can be a promising candidate for different applications including supercapacitors and FR products.

Fabrication of magnesium indium oxide (MgIn2O4) based on rGO for supercapacitor application

In recent decades, researchers have gained interest in metal-based oxide with carbon for supercapacitive electrode material primarily due to their exceptional power density, larger active surface area, distinctive reversibility and cost-effectiveness. This study provides the novel fabrication of MgIn2O4 (MIO) and MgIn2O@rGO via hydrothermal technique regarding supercapacitor electrodes. The supercapacitive properties of MgIn2O4 (MIO) and MgIn2O@rGO nanostructures were assessed in an aqueous 2.0 M KOH electrolytic solution using various electrochemical analyses. The synthesized MIO@rGO nanostructures demonstrated a brilliant capacitance of 986.09 F g−1 at 10 mV s−1 obtained from CV analysis. Additionally, it demonstrates excellent capacitive performance when combined with rGO and MIO@rGO composite demonstrated the specific capacitance values of 1589.15, 784.93, 674.53 and 452.47 F g− 1 at the current density ranges from 1 to 4 A g− 1, respectively from GCD investigation and also it attained a maximal energy of 59.82 Wh kg−1 and power density of 260.31 W kg−1. Therefore, the newly created material can be utilized in future generations on energy-storing systems, supercapacitor electrodes and energy conversion technologies.

Free-standing and flexible polyvinyl alcohol-sodium alginate-polypyrrole electrodes based on interpenetrating network hydrogels

Flexible supercapacitors (FSCs) have attracted much attention due to their strong mechanical flexibility, wearability and portability, which greatly rely on the employed flexible electrodes. The conductive polymer hydrogels with excellent flexibility, processability and capacitive performance are one of the most promising candidates, which are still limited by their poor mechanical properties. Constructing robust interpenetrating polymer networks (IPN) is an effective approach to promote their mechanical properties. Herein, interpenetrating polyvinyl alcohol (PVA)-sodium alginate (SA)-polypyrrole (PPy) hydrogels are prepared by the freeze–thaw and in-situ polymerization method. The IPN structure composed of PVA and SA not only enhances the mechanical properties of hydrogels, but also provides substantial active sites for electrochemical reactions. Moreover, the hydrogen-bonding interaction between different components in the PVA-SA-PPy hydrogel boosts the charge/ion transfer. The optimal PVA-SA-PPy hydrogels show an elongation at break of 380 %, a tensile strength of 1.5 MPa, and a specific capacitance of 2646 mF cm−2 at 2 mA cm−2. The symmetric PVA-SA-PPy FSCs show an energy density of 96.7 μWh cm−2 at a power density of 999.9 μW cm−2, and the capacitance retention is 66.3 % after 10,000 cycles. These exceptional mechanical and electrochemical properties make the PVA-SA-PPy hydrogels a promising candidate for FSCs.

Study of Nd-NiMoO4 Nanocomposites Prepared by Sol–Gel Method and Their Capacitive Properties

In this paper, NiMoO4 electrode materials doped with different concentrations of Nd rare earth metals were prepared by sol–gel method. Its morphology, structure, and spectral analysis were characterized by different scanning instruments, and the experimental results show that the NiMoO4 electrode material after adding 0.5% Nd doping showed excellent capacitance performance, with a specific capacity of 2182 F/g at a current density of 1 A/g. The capacitance retention was still 98.5% after 10,000 cycles at a current density of 5 A/g, which has a better electrochemical performance compared with the NiMoO4 material with superior electrochemical performance. In addition, an asymmetric capacitor device was prepared using 0.5% Nd-NiMoO4 material and CNTs as positive and negative electrodes, respectively, and the device showed a high energy density of 73.5 Wh/kg. In addition, the capacitor device still had a capacitance retention of 91.9% after 10,000 cycles. This paper provides an effective reference route for the preparation of rare-earth-doped bimetallic oxide electrode materials.

Nitrogen enriched high specific surface area biomass porous carbon: A promising electrode material for supercapacitors

In this report, a hierarchical porous activated carbon material with interconnected micro-meso-macro pores was prepared and studied with biomass waste as the starting point and transformation into high-value materials as the destination. Based on biomass hazelnut shell, a porous carbon material with a large specific surface area (3374 m2 g−1), rich pore structure, and suitable nitrogen content is constructed with polypyrrole as nitrogen source and KOH as the activator. Because of its unique pore structure, large specific surface area, and suitable nitrogen content, the prepared material as supercapacitor electrodes showed excellent capacitive performance (334 F g−1 at 0.5 A g−1), good rate capacity, and cycle stability. The experimental results show that the introduced nitrogen-containing functional groups endow the material with large pseudo-capacitance, which is conducive to increasing the specific capacitance. In addition, the symmetrical supercapacitor devices assembled on the basis of the material also showed excellent performance with an energy density of 11.4 W h kg−1 at a power density of 300.4 W kg−1. This synthetic strategy shows that the preparation of high-value electrode materials from biomass waste is promising.

Changing the potassium-based activation path to prepare coal-based porous carbon with more graphitic or graphene structures for high-performance organic supercapacitors

Graphitic porous carbon is becoming an excellent platform for high-performance supercapacitors due to its unique structural characteristics, especially the combination of high specific surface area and long-range ordered sp2 carbon framework, which can synergistically improve the ion transfer/storage capability and the structural stability during long-term cycling. However, the trade-off contradiction between porosity and graphitization of carbon materials is difficult to circumvent by traditional chemical or physical activation strategies. Herein, we changed the conventional potassium-based activation pathway by introducing a pre-carbonization process, thus transforming low-rank coal precursors into graphitic porous carbon with more graphite or graphene structures. Raman mapping characterization was introduced to comprehensively reveal the distribution of crystalline carbon within the obtained carbon materials, confirming that enhancing the structural maturity of carbon-based precursors by introducing a pre-carbonization process promotes the deep and uniform development of graphitized structures during the KOH activation process. Typical reaction intermediate characterization indicates that the reason for this structural transformation is due to a change in the primary form of potassium species under the changed activation pathways, leading to a solid-liquid phase reaction environment mediated by molten K2CO3. The obtained graphitic porous carbon possesses simultaneously a hierarchically porous structure with specific surface area of 2456 m2 g−1 and well-developed graphitic carbon crystalline by which the constructed organic supercapacitor delivers excellent capacitance and rate performance, along with a high energy-power density, and a lifespan exceeding 10,000 cycles. The elucidated potassium-based activation mechanism facilitates the easy adjustment of carbon porosity and crystalline structures to meet varying requirements in different application scenarios.

Polyacrylonitrile-sodium lignosulfonate -derived nitrogen-doped three-dimensional hierarchical porous carbon for supercapacitors

Modulation of pore structure and heteroatom doping are very important strategies to improve the electrochemical properties of carbon electrode materials. This report investigates the use of biomass-derived nitrogen-doped porous carbon materials to address the challenge of the specific capacitance and energy density in supercapacitors. Nitrogen-doped three-dimensional hierarchical porous carbon materials were prepared using a polyacrylonitrile/sodium lignosulfonate composite monolith as a precursor by thermally induced phase separation and subsequent carbonization/activation. This method precisely controls the structure and surface properties of porous carbon materials by regulating the structure of the precursor and situ doping of nitrogen, which is a valuable strategy for the controllable regulation of the pore structure for nitrogen-doped porous carbon materials. The resulting carbon material displayed excellent capacitance performance, exhibiting a high specific capacitance of 325.7F g -1 at a current density of 0.5 A/g, maintaining initial capacitance retention of 90.1 % at a current density of 5 A/g after 10,000 cycles. When investigated for practical applications, the assembled supercapacitor device had a higher energy density (9.88 W h kg- 1), which is higher than commercial carbon-based supercapacitors.

Two new 6-nitrobenzimidazole ligand-modified polymolybdate-based metal–organic complexes with excellent capacitive and electrocatalytic performances

6-Nitrobenzimidazole ligand was first introduced into polyoxometalate-based metal–organic architecture, and two unique butterfly-like complexes were obtained. Their applications in electrochemical energy storage and electrocatalysis were studied.

Protective hydrothermal treatment to improve ion pathway in Ti3C2Tx MXene for high-performance flexible supercapacitors

The strong re-stacking of Ti3C2Tx MXene nanosheets severely blocks ion transport pathway and sacrifices electrochemical performance. Here, a protective hydrothermal treatment is used to improve ion pathway in Ti3C2Tx MXene. The protective hydrothermal treatment is simply conducted in the hydrothermal kettle (filled with N2 atmosphere) placed in vacuum oven. The optimal Ti3C2Tx is achieved by the hydrothermal treatment of 150 °C for 12h, and recorded as h-Ti3C2Tx@150 °C/12h. The h-Ti3C2Tx@150 °C/12h film electrode achieves significantly improved ion transport pathways and enhanced ion accessibility with more pseudocapacitive active sites due to the increased interlayer spacing and pores as well as decreased flake size. According to DFT calculations, a small number of oxides (TiO2 nanoparticles) produced during the hydrothermal treatment also facilitate to increase the capacitive performance of h-Ti3C2Tx@150 °C/12h. Therefore, the h-Ti3C2Tx@150 °C/12h film electrode achieves significantly increased capacitance and rate performance. The h-Ti3C2Tx@150 °C/12h film electrode exhibits excellent capacitance (498.3 F g−1 and 1911 F cm−3 at 1 A g−1) and rate performance (63 % retention from 1 to 20 A g−1) with high cycling stability (98.2 % retention after 20 000 cycles), which are among the best electrochemical performances of undoped Ti3C2Tx based film electrodes reported so far. Thick h-Ti3C2Tx@150 °C/12h film electrode of 33.1 μm thickness exhibits an ultra-high areal capacitance of 3.23 F cm−2 at 1 A g−1. Moreover, the h-Ti3C2Tx@150 °C/12h-based flexible symmetric supercapacitor device exhibits excellent energy storage performance (117 F g−1 at 0.5 A g−1 and 23.4 Wh kg−1 at 299.8 W kg−1) with high cycling stability (84 % retention after 3000 cycles) and bending stability, outperforming most of previously reported Ti3C2Tx-based flexible supercapacitors. The impressive results indicate the great application potential of the h-Ti3C2Tx@150 °C/12h film in flexible energy storage devices.

Graphene nanosheet-supported ultrafine RuO2 quantum dots as electrochemical energy materials

Ruthenium oxide (RuO2) shows great promise as an electrode material for supercapacitors, which are energy storage devices that have large power densities. However, RuO2 materials suffer low surface area, poor electrical conductivity and a tendency to aggregate after reactions, limiting their rate capability and cycle stability and can lead to inadequate redox reactions with electrolytes. To address these problems, this work synthesized homogeneous ultrafine-RuO2 quantum dots (QDs) materials with a size of around 2 nm on the surface of graphene nanosheets (GNS) via a facile hydrothermal method. The small size and uniform distribution of RuO2 QDs in the composite electrode material allowed for a high concentration of active adsorption sites for ions in the electrolyte while also facilitating efficient electrochemical redox reactions. The resulting RuO2/GNS composite exhibited a large specific area of 177.34 m2g‐1 and demonstrated an excellent capacitance performance of 1138.5 Fg‐1 at a current density of 0.5 Ag‐1. Additionally, a retention rate of 91.4 % when applying current densities from 0.5 to 10 Ag‐1 and cycling stability with 94.5 % retention after 20000 cycles, demonstrates the occurrence of a rapid and reversible faradaic redox reaction on the electrode surface. The symmetrical supercapacitor configuration with two identical RuO2/GNS electrodes was fabricated and demonstrated a high capacity (309.16 Fg‐1 at a current density of 0.5 Ag‐1) and an outstanding retention rate of 91.2 % at a current density of 10 A g−1). A device operated within a 1.8 V potential window showed high energy density from 126 Whkg‐1 to 139.2 Whkg‐1 and a power density from 440.1 Wkg‐1 to 8494.4 Wkg‐1 at current densities ranging from 0.5 Ag‐1 to 10 Ag‐1, respectively. This ultrafine-RuO2 quantum dots composite is a potentially promising advanced functional electrode material for electrochemical applications beyond supercapacitors and may be suitable for a broader range of energy storage and conversion applications.

Fabrication of nanoflower-like Ni2Co-S/CNTA with morphology controlled for high-performance supercapacitor

Morphology and structure regulation is considered to be an effective strategy to improve the energy storage performance of supercapacitor electrode materials. In this work, a series of graded Ni2Co-S/CNTA nanoflowers composed of self-assembled nanosheets or nanorods have been synthesized by nitrilotriacetic acid (NTA)-assisted hydrothermal strategy. Morphological analysis shows that the micromorphology of the unit structures made up nanoflowers can be controlled by adjusting the concentration of NTA. Thanks to the synergistic effect of high void space, hierarchical assembly mode and integrated composite structure, Ni2Co-S/CNTA nanoflowers promote the full exposure of rich active sites, it enhances the stability of the structure, and impart excellent energy storage performance. As expected, the optimized Ni2Co-S/CNTA-2 electrode exhibits excellent capacitive performance, including high specific capacitance (1670.2 F g−1 at 1.0 A g−1) and good cycle stability (86.5% after 5000 cycles). The maximum energy density of Ni2Co-S/CNTA-2//AC ASC device is 61.3 Wh·kg−1 at a power density of 816.7 W·kg−1 and its retention rate is 88.3% after 5000 cycles.

Mild and Efficient One-Step Synthesis of Nitrogen-Doped Multistage Porous Carbon for High-Performance Supercapacitors.

Biomass-derived carbon materials have broad application prospects in energy storage, but still face problems such as complex synthesis paths and the massive use of corrosive activators. In this study, we proposed a mild and efficient pathway to prepare nitrogen-doped porous carbon material (N-YAC) using one-step pyrolysis with solid K2CO3, tobacco straw, and melamine. The optimized material (N-YAC0.5) was not only enriched with nitrogen, but also exhibited a high specific surface area (2367 m2/g) and a reasonable pore size distribution (46.49% mesopores). When utilized in electrodes, N-YAC0.5 exhibited an excellent capacitance performance (338 F/g at 1 A/g) in the three-electrode system, and benefitted from a high mesopore distribution that maintained a capacitance of 85.2% (288 F/g) at high current densities (20 A/g). Furthermore, the composed symmetric capacitor achieved an energy density of 14.78 Wh/kg at a power density of 400 W/kg. In summary, our work provides a novel and eco-friendly approach for converting biomass into high-performance energy-storage materials.

Simultaneous Inhibition of Conduction Loss and Enhancement of Polarization Intensity of Polyetherimide Dielectrics for High-Temperature Capacitive Energy Storage.

Polymer dielectrics with excellent high-temperature capacitive energy storage performance are in urgent demand for modern power electronic devices and high-voltage electrical systems. Nevertheless, the energy storage capability usually degrades dramatically at increased temperatures, owing to the exponentially increased conduction loss. Herein, a trace of commercially available aluminum nitride (AlN) nanoparticles is incorporated into the poly(ether imide) (PEI) matrix to inhibit the conduction loss. The nanostructured AlN component with a large specific surface area can provide abundant sites for the collision of carriers. More importantly, the generated new trap energy levels can immobilize the carriers, accordingly contributing to the reduction in leakage current. From this, the discharged energy density at 150 °C of PEI composites increases by 82.13% from 2.63 J/cm3 for pristine PEI to 4.79 J/cm3 for PEI composites. This work establishes a facile approach to enhancing the high-temperature capacitive performance of polymer dielectrics.

Ultrasound-assisted synthesis of ruthenium-decorated titanium boride nanocomposite structures for high-performance supercapacitors

TiB2 is extensively explored due to its outstanding properties, for example, high electrical conductivity, high thermal conductivity, chemical stability, high hardness, low density, and solidity. Herein, we developed a novel nanocomposite structure (NCS) featuring exfoliated TiB2 decorated with Ru nanoparticles, denoted as exfoliated TiB2@Ru. This novel electrode material was synthesized using an ultrasound-assisted method. Both the pristine TiB2 and exfoliated TiB2@Ru NCS were characterized by FTIR, XRD, FE-SEM, EDX, AFM, and XPS analyses. Furthermore, the electrochemical characteristics of all TiB2 electrodes were measured by CV, GCD, and EIS to evaluate their application to supercapacitors. The exfoliated TiB2@Ru NCS exhibited an enhanced specific capacitance of 744 F/g compared with exfoliated TiB2 (464 F/g) and pristine TiB2 (296 F/g) at a current density of 1 A/g in 3 M KOH electrolyte solution using a three-electrode system. The as-prepared exfoliated TiB2@Ru solid-state supercapacitor delivered a significantly higher capacity retention of 97 % than the pristine TiB2 (92 %), even after 5000 cycles. Therefore, the interconnected sheet-like exfoliated TiB2@Ru NCS electrode offers excellent capacitive performance for energy storage applications. As a result, the design and/or suitability for improving highly active electrochemical sites in exfoliated TiB2 through the incorporation of Ru nanoparticles by ultrasonic method showed excellent charge storage performance.

Urea-boosted gas-exfoliation synthesis of lignin-derived porous carbon for zinc ion hybrid supercapacitors

Porous carbons are the favorable candidate cathode for the emerging zinc ion hybrid supercapacitors (ZHSCs). The scale-up production of porous carbon requires green synthesis methods to replace the existing corrosive KOH activation, but most mild activators suffer from low activation efficiency, leading to the inferior surface area and capacitance. Herein, we propose a urea-boosted gas-exfoliation method using K2C2O4 as the mild activator and lignin as the low-cost precursor. Urea has the auxo-action to lower the decomposing temperature of K2C2O4 and to initiate an extra second-step gas-exfoliation. The auxo-action produces the enlarged surface area of porous carbon from 592 m2/g to 1949 m2/g and promotes the morphology regulation from thick carbon bulks to layered carbon sheets. The improved carbon structure contributes to the excellent capacitive performance with a high energy-power density of 126.71 Wh kg−1 at 79.37 W kg−1. Moreover, the energy-storage mechanism is studied by both electrochemical analysis and Density Functional Theory (DFT) method. The DFT calculation demonstrates the effect of interaction between N- and O-containing groups on the adsorption capacity of zinc ions, which can provide information for the structural optimization design of carbon cathode.