Capacitance Of Supercapacitor Research Articles

Enhancing the capacitance and robustness of graphene supercapacitors by adding a coating of activated-carbon/Bi2Al4O9 on their electrodes

Recently, using activated carbon (AC) for supercapacitors (SCs) has attracted attention because such carbon can be easily derived from bio-waste. However, the capacitance of the AC based SCs is in general low. For this reason, we present in this research the synthesis of AC from aquatic water-lily plant, which is considered a pest. First, SCs were fabricated only with graphene electrodes and produced a capacitance (Cs)/Energy-density (E) of 150.3 F g-1/30.1 Wh kg-1. Later, a coating of AC was deposited on the graphene electrodes and now the devices had higher Cs and E of 446.7 F g-1 and 89.4 Wh kg-1, respectively. The Cs/E of the devices was enhanced even more to 641.9 F g-1/128.3 Wh kg-1 after depositing a composite powder of AC/Bi2Al4O9 (BiAl) on the SC electrodes. Thus, the capacitance increased by 197% and 327% after introducing AC and AC/BiAl to the SCs. Other benefits of introducing the AC/BiAl composite to the electrodes were: i) the output voltage was enhanced 40% with respect to the device made with only AC; ii) the capacitance retention for 1000 bending cycles was maintained over 95%, this means that adding the AC/BiAl to the SC electrodes increased the mechanical resistance/stability of the devices; iii) the SCs produced a constant operating voltage of 0.33 V when they immersed in motor oil, which is not commonly reported in the literature; and iv) the SCs maintained a voltage of 0.37 when they are subjected to bending in real time. If no BiAl is added to the SC electrodes, the output voltage is lower (0.15 V). On the other hand, Raman and XPS spectroscopies demonstrated that the devices made with AC/BiAl had on their electrodes oxygen vacancies and chemical species such as: Bi5+/Bi3+/Bi0 and Al3+/Al0, which worked as redox centers for the charge storage. In general, this work demonstrated that it is possible the fabrication of AC-based SCs with capacitances that surpass the values already reported in literature for devices made with AC (50–150 F g-1). Also, we confirmed that adding BiAl to the system increased the robustness (mechanical/electrochemical stability) of the devices, which is of interest for the flexible electronics.

Role of the MnCoGe alloys to enhance the capacitance of flexible supercapacitors made with electrodes of recycled aluminum and carbon nanotubes

Flexible and sustainable supercapacitors (SCs) were fabricated with carbon nanotubes (CNTs) as the anode and recycled aluminium as the cathode (obtained from soda cans). Devices made with the configuration of CNT//Al had maximum energy-densities/capacitances of 97.8 Wh kg−1/313.5 F g−1. Later, MnCoGe (MCG) alloy powders doped with boron (MCG:B) or gallium (MCG:Ga) were incorporated into the SC electrodes and the energy-density/capacitance was enhanced up to 269.5 Wh kg−1/862.3 F g−1. This outstanding increment of the electrochemical performance was caused by the formation of multiple redox centers on the SC electrodes (oxygen vacancies, Mn3+/Mn4+, Co2+/Co3+, and Ge4+/Ge2+/Ge0) as confirmed by XPS and Raman spectroscopies. The SCs made with MCG alloys were immersed in acid (pH=3)/basic (pH=11) aqueous media and electrochemically tested. Surprisingly, the capacitance retention was reduced a maximum of 0.6%, demonstrating their capacity to operate underwater. The tests of bending and charging/discharging cycles demonstrated that the SCs made with the MCG:B powder were the most stable because their capacitance retention was above 95%. In contrast, SCs made with the MCG:Ga alloy had capacitance retentions below 93% after the same tests. Overall, we demonstrated that efficient/flexible/waterproof SCs can be made with low-cost aluminium, which of interest for wearable electronics.

Microwave construction of the 3D porous interconnected structure of NiCoCr medium-entropy alloy with ultra-high specific capacity for supercapacitors and electrocatalysis

The effective design of bifunctional electrodes with unique morphology and remarkable electrochemical properties for energy conversion and storage devices is a promising but challenging endeavor. Herein, self-supporting NiCoCr medium-entropy alloy (MEA) with a hierarchical porous network structure was in situ synthesized on nickel foam (NiCoCr/NF) by a simple and rapid microwave route. The optimal NiCoCr/NF presented an ultra-high specific capacity of 3011.8 C g−1 (1 A g−1) and outstanding charge/discharge sustainability (83.4% retention at 10 A g−1 over 50,000 cycles) due to its multi-component synergistic effect and hierarchical porous structure. Meanwhile, subtle lattice distortions and electron density redistribution in the NiCoCr MEA tuned electronic structures, resulting in a low overpotential and Tafel slope. Aqueous and solid-state asymmetric supercapacitors were fabricated by using NiCoCr/NF as a cathode and Bi/NF as an anode. The aqueous supercapacitor displayed an exceptional energy density of 314.4 Wh kg−1 at a power density of 800 W kg−1 with 81.8% retention at 10 A g−1 over 20,000 cycles. This study provides a new strategy for the efficient synthesis of electrode materials with interconnected network structures and paves the way for the broader application based on medium-entropy and high-entropy materials as promising candidates for future energy storage devices.

S doping induced phase transition of CoMoO4 and decorated on KCu7S4 for high specific capacitance supercapacitor electrode material

Due to the importance of electrode materials for supercapacitors, modified transition metal compounds are better suited to their needs. Compounding and ion doping are two effective modification pathways to optimize the structure of electrode materials and enhance the ion migration kinetics, and thus improve the electrochemical performance of transition metal compounds. In this paper, KCu7S4@S-CoMoO4 (S doping) was prepared by a two-step hydrothermal method. The S doping would cause the phase transition of CoMoO4 and enhance crystallinity. Additionally, the possible substituted oxygen position of S atom was simulated by density functional theory (DFT). Electrochemical characterization showed that the specific capacitance of KCu7S4@S-CoMoO4 prepared under optimal condition was as high as 2866.77 F/g at a current density of 0.5 A/g. The assembled KCu7S4@S-CoMoO4//AC hybrid supercapacitor exhibits the maximum energy density of 132.71 Wh/kg in liquid system condition and the specific capacitance maintained 80.9% of the initial capacitance after 3500 charge/discharge cycles. This work provides ideas for designing materials with high electrochemical performance.

Solvent-Controlled Synthesis of Zn–Co–S@Ni12P5 Arrays with Ultra-High Specific Capacitance for Hybrid Supercapacitor

Solvent-Controlled Synthesis of Zn–Co–S@Ni₁₂P₅ Arrays with Ultra-High Specific Capacitance for Hybrid Supercapacitor

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.

Interdigitated supercapacitor with double-layer active material prepared by sacrificial layer method

Increasing the surface area of active materials is a crucial approach to enhance the capacity of supercapacitors. In this study, we present an interdigitated supercapacitor featuring a double-layer active material prepared using a sacrificial layer method. The replacement of the insulating substrate with a gel electrolyte facilitates ion motion between the active electrodes. Finite element analysis (FEA) and electrochemical experiments confirm that the utilization of double-layer active material can significantly improve the capacity (1.5–1.85 times higher than traditional structures). The electrochemical performance of the three active materials has been significantly improved after using the double-layer active material structure, which proves that the method in this paper has strong material compatibility. Furthermore, an interdigital supercapacitor (ISC) is fabricated using electrodes with double-layer active material through the sacrificial layer method and its electrochemical performance is evaluated. At a scan rate of 10 mV·s-1, ISC exhibits an impressive area-specific capacitance as high as 68.4 mF·cm-2. Remarkably, ISC can maintain stable power output even under extreme deformation and fatigue testing conditions. This strategy involving interdigitated supercapacitors with double-layer active materials prepared via the sacrificial layer method presents a promising solution for flexible energy storage devices.

Evaluation of electrochemical performance of supercapacitors from equivalent circuits through cyclic voltammetry and galvanostatic charge/discharge

Conventional methods used to analyze electrochemical performance of supercapacitors are complex and cannot illustrate the asymmetrical behavior of charge and discharge curves and the variation of resistance with scan rate and current density. In this work, we propose a simple method to calculate total capacitance and internal resistance of supercapacitors with equivalent circuits and discuss the mechanisms responsible for the asymmetry of galvanostatic charge discharge (GCD) curves. Using the equivalent circuits, we demonstrate the feasibility of analyzing electrochemical performance of supercapacitors from the current-voltage curve for cyclic voltammetry (CV) and the GCD curves for galvanostatic cycling. A series of supercapacitors are constructed, in which the electrodes are pre-compressed under a compressive stress in a range of 1– 7.5 MPa. The experimental results reveal that the total capacitance of the supercapacitors increases with increasing the pre-compressive stress and validated the proposed method. Increasing the pre-compressive stress likely can improve the electrochemical performance of supercapacitors. The results from the analysis with the analytical relations for the resistance of the resistor in parallel connection in the three-element circuit approaching infinity exhibit similar trends to the corresponding ones from the conventional methods in contrast to the results from the three-element circuit, which exhibit different trends. The three-element circuit with the resistor in parallel connection approaching infinity can be used to analyze the electrochemical performance of supercapacitors for both the CV and GCD operational conditions.

Enhancement of capacitance of waterproof supercapacitors by controlling the thickness of their composite electrodes (graphene/ La0.2Gd1.8Zr2O7: La0.7Sr0.3MnO3)

We report the electrochemical performance of wrinkled/washable graphene-based supercapacitors (SCs). Sustainable graphene electrodes were fabricated by printing graphene microplates on recycled plastics (taken from wasted chip-packets), which provided flexibility to the SCs. The devices made with only graphene electrodes had an energy-density/specific-capacitance of 8.8 Wh kg−1/99.1 F g−1. To enhance the electrochemical properties of the SCs, a mixture of La0.2Gd1.8Zr2O7 (LGZ) and La0.7Sr0.3MnO3 (LSM) perovskites (redox materials) were added on their electrodes. After this, the energy-density/capacitance was enhanced to 53.1 Wh kg−1/596.90 F g−1, that is, an improvement of 503/502%, respectively. Subsequently, the solid state SCs were completely rolled or wrinkled, in consequence, the capacitance decreased by 12.1 and 35.6%, respectively. Even more, the SCs were immersed in water or subjected to washing/drying cycles using a washing-machine and the capacitance barely decreased by ⁓14.2%. Additionally, the thickness of the SC electrodes was varied in the range of 65–400 μm and obtained the maximum capacitance for a thickness of 330 μm. Overall, we demonstrated that incorporating the LGZ/LSM perovskite on the SC electrodes provided extra redox centers, which incremented the capacitance of the devices. The SCs reported here are waterproof and wrinkled, thus, they could provide energy to wearable devices.

Application of Copper-Sulfur Compound Electrode Materials in Supercapacitors.

Supercapacitors (SCs) are a novel type of energy storage device that exhibit features such as a short charging time, a long service life, excellent temperature characteristics, energy saving, and environmental protection. The capacitance of SCs depends on the electrode materials. Currently, carbon-based materials, transition metal oxides/hydroxides, and conductive polymers are widely used as electrode materials. However, the low specific capacitance of carbon-based materials, high cost of transition metal oxides/hydroxides, and poor cycling performance of conductive polymers as electrodes limit their applications. Copper-sulfur compounds used as electrode materials exhibit excellent electrical conductivity, a wide voltage range, high specific capacitance, diverse structures, and abundant copper reserves, and have been widely studied in catalysis, sensors, supercapacitors, solar cells, and other fields. This review summarizes the application of copper-sulfur compounds in SCs, details the research directions and development strategies of copper-sulfur compounds in SCs, and analyses and summarizes the research hotspots and outlook, so as to provide a reference and guidance for the use of copper-sulfur compounds.

Design of bifunctional sandwich-like Co@Si/Ox-MXene nanocomposite to increase the supercapacitor properties and removal of pollutants from wastewater

Spent supercapacitor electrodes are considered waste after the end of the cycle. Designing a multifunctional material to increase the specific capacity of supercapacitors and eliminate environmental pollution is one of the existing challenges. In this study, Co3O4 was extracted from waste CMB by several tandem hydrothermal methods. Also, 3-Aminopropyl-triethoxysilane (APTES) was used to exfoliate and surface modification of Ti3C2Tx MXene nanosheets. Then, by assembling Co3O4 on the synthesized Ti3C2Tx nanosheet, a sandwich composite of Co@Si/Ox-Ti3C2Tx was formed through the formation of a complex with active surface functional groups on the oxalic acid modified MXene surface. Co3O4 can increase the number of redox reaction sites and fast charge transfer in the conducting channels of MXene by penetrating interlayers. The Co@Si/Ox-Ti3C2 composite electrode showed an increased specific capacity of 1821 Cg−1 at a current density of 1 Ag−1. The prepared hybrid supercapacitor (HSC) with Co@Si/Ox-Ti3C2 composite as the positive electrode and silanized active nanocarbon (Si69@AC) with bis(triethoxysilylpropyl)tetrasulfide as the negative electrode had a high energy density of 50 Wh kg−1 up to a power density of 8422 W kg−1 along with excellent cyclic life of 90.87% capacitance retention. After 15,000 cycles, XRD and XPS analyses confirmed 62% degradation of the positive electrode and conversion to TiO2 after 30 days in water. To graft the separated and agglomerated elements, they were added to the TEOS solution and subjected to the sol-gel process. High photocatalytic properties, 97% degradation of methylene blue (MB), changing the absorption region from UV to visible due to changing its band gap to 3.3 eV were among the characteristics of the new material. This work is a new approach for the construction of eco-friendly new HSCs.

Preparation of transition metal oxide mixed graphene electrode materials and its application in supercapacitors

The increasing prevalence of wearable electronic devices in contemporary society has led to heightened expectations for energy storage devices. These expectations encompass not only high power density and energy density, but also robust stability and resistance to bending. Consequently, the design and development of supercapacitors with versatile functionalities has emerged as a prominent area of research. The electrode material, which is one of the elements that can have the biggest impact on the operation of supercapacitors, has been the subject of numerous scientific advancements over the years. One promising approach is the combination of transition metal oxide and graphene material composite. By conducting a comprehensive review of relevant literature, this study synthesizes preparation methods from multiple sources, integrates the benefits of multiple technologies to develop a novel preparation method utilizing ultrasonic shock and the two-step interface self-assembly method, and compares the physical and chemical properties of different transition metal oxide mixed graphene electrode materials and their application in supercapacitors. In conclusion, the preparation methods of transition metal oxide mixed graphene electrode materials typically control their microscopic morphology in order to support structure, agglomeration, and spalling reduction, thereby enhancing the specific capacitance and cycle stability of supercapacitors and achieving the desired result of increasing specific surface area and support structure.

M-Ni-Co MOF (M=Zn, Fe, Mn) for high-performance supercapacitors by adjusting its morphology

Metal-organic frameworks (MOF) have been wildly synthesised and studied as electrode materials for supercapacitors, and bimetallic MOF of Ni and Co has been broadly studied to enhance both specific capacitance and stability of supercapacitors. Herein, a best performance (about 320 F/g) of Ni–Co bimetallic MOF was found in a uniform preparation condition by adjusting the ratio of Ni to Co. Then tiny third metal ion was introduced, and we found that the morphology of material has a significant change on the original basis. Furthermore, certain ions (Zn, Fe, Mn) introduced make a huge improvement in capacitance based on Ni–Co MOF of 320 F/g. The result shows that Zn–Ni–Co MOF, Fe–Ni–Co MOF and Mn–Ni–Co MOF perform specific capacitance of 1135 F/g, 870 F/g and 760F/g at 1 A/g, respectively. Meanwhile, the asymmetric supercapacitor (ASC) was constructed by Zn–Ni–Co MOF as positive electrode and active carbon (AC) as negative electrode. The Zn–Ni–Co MOF//AC ASC possesses a energy density of 58 Wh/kg at a power density of 775 W/kg. This research provides a new methods to regulate the morphology of MOF and a novel viewpoint for assembling high-performance, low-price, and eco-friendly green energy storage devices.

Advancement in Supercapacitors for IoT Applications by Using Machine Learning: Current Trends and Future Technology

Supercapacitors (SCs) are gaining attention for Internet of Things (IoT) devices because of their impressive characteristics, including their high power and energy density, extended lifespan, significant cycling stability, and quick charge–discharge cycles. Hence, it is essential to make precise predictions about the capacitance and lifespan of supercapacitors to choose the appropriate materials and develop plans for replacement. Carbon-based supercapacitor electrodes are crucial for the advancement of contemporary technology, serving as a key component among numerous types of electrode materials. Moreover, accurately forecasting the lifespan of energy storage devices may greatly improve the efficient handling of system malfunctions. Researchers worldwide have increasingly shown interest in using machine learning (ML) approaches for predicting the performance of energy storage materials. The interest in machine learning is driven by its noteworthy benefits, such as improved accuracy in predictions, time efficiency, and cost-effectiveness. This paper reviews different charge storage processes, categorizes SCs, and investigates frequently employed carbon electrode components. The performance of supercapacitors, which is crucial for Internet of Things (IoT) applications, is affected by a number of their characteristics, including their power density, charge storage capacity, and cycle longevity. Additionally, we provide an in-depth review of several recently developed ML-driven models used for predicting energy substance properties and optimizing supercapacitor effectiveness. The purpose of these proposed ML algorithms is to validate their anticipated accuracies, aid in the selection of models, and highlight future research topics in the field of scientific computing. Overall, this research highlights the possibility of using ML techniques to make significant advancements in the field of energy-storing device development.

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.

Improving the capacitance of hydrogel-based supercapacitors by pre-depositing a zwitterionic 3,4-ethylenedioxythiophene

Polymer hydrogel electrolytes show great advantages in the flexible electronic applications of supercapacitors, but the poor interfaces between electrode and electrolyte are limiting their energy and power densities. In this work, by taking the well-developed pair of poly(vinyl alcohol)/H2SO4 gel electrolyte and graphene film electrode as a prototype, after electrochemically depositing a functional monomer of zwitterionic 3,4-ethylenedioxythiophene (EDOTSB) onto the graphene film electrodes, the specific capacitance of supercapacitors receives a 2.5-fold increase up to 248 mF cm−2 (346 F g−1). By comparing with other pendent groups on EDOT, the decisive role of the zwitterionic group is demonstrated. Attributed to the strong hydration ability of the zwitterion group, the deposition of EDOTSB effectively improves the hydrophilicity of graphene film electrodes, so that the interfacial affinity between the electrode and hydrogel electrolyte is greatly promoted. On the one hand, the EIS measurements certify that the charge-transfer resistance is largely reduced. On the other hand, tests with electrochemical quartz crystal microbalance demonstrate that the interior of graphene film is highly accessible for EDOTSB, thereby enlarging the accessible surface area on the electrode and accelerating the electrolyte infilling process. Furthermore, the general comparison with the liquid electrolyte counterpart is also discussed. This developed method is highly universalizable and can find applications in different electrode/electrolyte supercapacitors and other high-performance flexible energy storage devices.

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.

Research on capacity allocation of supercapacitor absorbing transient energy based on non-dominated sorting genetic algorithm II

During the actual operation of the power system, various situations will be encountered. A slight disturbance will generate a relatively large transient energy in the system. Estimating the loss and reducing the transient energy well is a very worthwhile research topic. In this paper, we discussed the charging and discharging capability of supercapacitors, proposed a scheme of using parallel supercapacitors to absorb the transient energy generated after grid faults, established a supercapacitor capacity optimization model based on economy and absorption effect, used the NSGA-II Algorithm to find the size of the optimum supercapacitor capacity, and finally carried out modeling and simulating in MATLAB/SIMULINK to verify the absorption effect of the optimal capacity configuration on transient energy.

High areal-capacitance based extremely stable flexible supercapacitors using binder-free exfoliated graphite paper electrode

The highly porous and binder-free flexible paper electrodes can enhance the specific capacitance of symmetric supercapacitors (SCs) due to their large surface and effective ion diffusion pathways. We synthesized the exfoliated graphite (ExG) by the thermal exfoliation method of chemically treated graphite flakes and compressed it into a paper-like thin sheet (binder-free) of ∼0.15 mm thickness. The coin cell SCs with copper (Cu) and stainless steel (SS) as current collectors have been fabricated for the electrochemical measurement. The cyclic voltammetry and galvanostatic charge/discharge measurements are investigated at various scan rates and current densities. The SCs with Cu foil as a current collector perform better than SS-based SCs. The Cu current collector-based SCs showed a specific capacitance of 37.08 mF cm−2, whereas it was ∼29.98 mF cm−2 for SS-based SCs at a 0.01 V s−1 scan rate across a 0–0.6 V potential window. Approximately no degradation in charge storage capacity for more than 15 000 cycles at 0.1 V s−1 shows the ultra-stability of the flexible ExG-based binder-free electrodes. A digital watch is powered using the fabricated pouch cell supercapacitor with copper-based current collectors to show the potential of SCs.

Two biomass material-derived self-doped (N/O) porous carbons from waste coriander and lilac with high specific surface areas and high capacitance for supercapacitors

In this study, two kinds of 3D self-doped (N/O) lilac-based and coriander-based porous carbons with high performance have been prepared.