High Electrochemical Performance Research Articles

An in-plane supercapacitor obtained by facile template method with high performance Mn–Co sulfide-based oxide electrode

Designing in-plane supercapacitors with high electrode materials selectivity is an indispensable approach to improve electrochemical performance. In this work, a facile template method was employed to fabricate in-plane supercapacitors. This template method could select any electrochemical active materials as electrode materials of in-plane supercapacitors. Hence, a high electrochemical performance material Mn–Co LDO-2S with optimized metal-sulfur bonds proportion and abundant sulfur vacancies was employed as electrode material of symmetrical in-plane supercapacitor (SPS). SPS exhibits excellent electrochemical performance finally, and has considerable area energy density 55.0 μWh cm−2 with an area power density of 0.7 mW cm−2. As a result, introducing sulfur atoms and sulfur vacancies are efficient approaches to improve electrode materials’ electrochemical performance, and template method that proposed in this work is a promising approach to widen selectivity of in-plane supercapacitors’ electrode materials.

Exceptionally High‐Performance Reversible Solid Oxide Electrochemical Cells with Ultrathin and Defect‐Free Sm0.075Nd0.075Ce0.85O2‐δ Interlayers

AbstractSolid oxide electrochemical cells (SOCs) are promising energy conversion and storage systems owing to their high efficiency and low environmental impact. To lower operating temperatures, the state‐of‐the‐art SOCs with highly active cobaltite‐based oxygen electrodes essentially require doped‐ceria interlayers to avoid undesirable reactions with commercially available zirconia electrolytes. However, the inherent cation interdiffusion between ceria and zirconia materials at high temperatures (>1300 °C) has retarded the construction of highly dense and stoichiometric ceria/zirconia bilayers. This study reports the fabrication of a highly conductive, ultra‐thin (250 nm), and defect‐free Sm0.075Nd0.075Ce0.85O2‐δ (SNDC) interlayer via readily processable gelatin‐assisted deposition. The SOC with the gelatin‐derived SNDC interlayer achieved exceptionally high electrochemical performances both in the fuel cell (≈3.34 W cm‐2) and electrolysis mode (≈2.1 A cm‐2 at 1.3 V) at 750 °C—one of the best records for SOCs with similar configuration to date—along with excellent long‐term durability (1500 h). Mechanistic analysis reveals that the ultra‐thin and dense structure of the SNDC interlayer provides a faster route for oxygen‐ion conduction and more active sites for both oxygen reduction and oxygen evolution reactions at the oxygen electrode/electrolyte interface. The findings suggest that the thin and dense gelatin‐derived SNDC interlayer has great potential for use in high‐performance reversible SOCs.

Unravelling the regulating role of graphene coating on improving the electrochemical performance of pyrophosphate cathode material: A first-principles study

Pyrophosphate (Li2FeP2O7, LFPO) is proposed as a promising cathode material for Li-ion batteries on account of the high voltage and the two-dimensional lithium ions diffusion channel. Graphene coating could effectively improve the inherent poor ionic and electronic conductivities of Li2FeP2O7 material, however, the interfacial interaction and regulating role of the graphene coating on the graphene/Li2FeP2O7 (G/LFPO) composite structures are lack of research at the atomic scale. With the aid of first-principles calculations and ab initio molecular dynamics (AIMD) simulations, the interaction mechanism of graphene on the LFPO cathode material has been systematically investigated in terms of the geometrical structure, thermodynamical stability, interfacial charge distribution and electronic property. The analysis of electron localization function (ELF), charge density differences, and density of states strongly suggest the G/LFPO(001) and G/LFPO(010) heterostructures exhibit high electrochemical performance. The AIMD simulations show that the parallel and perpendicular G/LFPO(001) and G/LFPO(010) heterostructures have high thermodynamical stabilities and electronic conductivities. The diffusion coefficients of Li+ ions in the G/LFPO heterostructures are noticeably enhanced. Our present work would not only provide a fundamental understanding of interfacial interaction and electrochemical properties of G/LFPO composite, but also shed light on the regulating mechanism for the potential phosphate-based cathode material with high electrochemical performance.

Correlating between the height of three-dimensional core-shell electrodes and ion transport for their electrochemical performance

The height of electrodes for in-situ grown 3D core-shell electrodes on a collector, which can directly affect the transport of electrolyte ions, is an important issue that needs to be concerned. Herein, nanocone Co2(OH)2CO3 (CCH) with different heights were synthesized as representative demos to explore the possible factors, including the height h, ion diffusion coefficient D, and Warburg coefficient σ for addressing the ion transport issue. A compromise balance between the height and ion diffusion coefficient was obtained after a series of dynamic analyses. The results showed that the optimal height of CCH can improve ion transport and shorten the charge transfer distance while avoiding stacking and curling. The best electrochemical performance renders the minimum Warburg and maximum ion diffusion coefficients. Furthermore, in-situ EIS and Raman showed that the active sites of CCH were the exposed Co in octahedral units, which can form linkage of octahedrally-electrolyte upon suitable cycling height can reveal more cations, thereby producing more extraordinary electrochemical performance. This work emphasizes the importance of ion diffusion behavior for electrochemical performance within electrodes. It gives a guide for constructing core-shell electrodes with a high electrochemical performance by engineering the microscopic height of materials.

Creation of an extrinsic pseudocapacitive material presenting extraordinary cycling-life with the battery-type material Co(OH)2 by S2− doping for application in supercapacitors

Some battery-type materials show the potential for storing high density energy in supercapacitors because of their high theoretical capacity. So far, the very unsatisfied electrochemical performance is still the label of these battery-type materials, which is attributed to their diffusion-controlled kinetics of energy storage. Some efforts try to transform their electrochemical behavior to extrinsic pseudocapacitive behavior through nanostructuring. However, the extrinsic pseudocapacitive materials are rare due to the restriction of no phase transformation. In this work, we propose an alternative strategy to create an extrinsic pseudocapacitive material from the typical battery-type material Co(OH)2 by S2− doping. The doped S2− ions further increase energybarrierfor the intercalation of OH− ions into the interlayer space of Co(OH)2, thus suppressing its bulk phase transformation. Also, the decreased OH− ions-Co(OH)2 interaction plus the surface reaction feature induced by S2− doping results in the pseudocapacitive behavior. Thus, the S2− doped Co(OH)2 presents the comprehensive electrochemical signatures of pseudocapacitive materials and an extraordinary cycling life of 200,000 charge-discharge cycles. This work initiates a new way for acquiring electrode materials with high electrochemical performance for application in supercapacitors.

Ultrasonically dispersed multi-composite strategy of NiCo2S4/Halloysite nanotubes/carbon: An efficient solid-state hybrid supercapacitor and hydrogen evolution reaction material

Herein, we have developed a novel hybrid material based on NiCo 2 S 4 (NCS), halloysite nanotubes (HNTs), and carbon as promising electrodes for supercapacitors (SCs). Firstly, mesoporous NCS nanoflakes were prepared by co-precipitation method followed by physically mixing with HNTs and carbon, and screen printed on nickel foam. After ultrasonication, a uniform distribution of the Carbon/HNTs complex was observed, which was confirmed by surface morphological analysis. When used as electrode material, the NCS/HNTs/C hybrid displayed a maximum specific capacity of 544 mAh g −1 at a scan rate of 5 mV s −1 . Later, a solid-state hybrid SCs was fabricated using activated carbon (AC) as the negative and NCS/HNTs/C as the positive electrode (NCS/HNTs/C//AC). The device delivers a high energy density of 42.66 Wh kg −1 at a power density of 8.36 kW kg −1 . In addition, the device demonstrates long-term cycling stability. Furthermore, the optimized NCS, NCS/HNTs, and NCS/HNTs/C nanocomposites also presented superior hydrogen evolution reaction (HER) performance of 201, 169, and 116 mV in the acidic bath at a current density of 10 mA cm −2 , respectively. Thus, the synthesis of NCS/HNTs/C nanocomposite as positive electrodes for hybrid SCs opens new opportunities for the development of next-generation high energy density SCs. • Synthesis of novel hierarchical NiCo 2 S 4 nanoflakes using a simple co-precipitation method with high electrochemical performance. • Preparation of final NiCo 2 S 4 /HNTs/C composite electrode by screen-printing method on Ni foam. • Improved the supercapacitor capacitive properties than the NiCo 2 S 4 /HNTs/C then the NiCo 2 S 4 and NiCo 2 S 4 /HNTs composite. • A novel NiCo 2 S 4 /HNTs/C//AC constructed solid-state hybrid device. • SSHSc shows a high energy density of 42.66 Wh kg −1 at a power density of 8.36 kW kg −1 .

Simple air blow to charge Li-air, rechargeable, solid-state batteries using nano-engineered aerogel structures

Lithium air (Li-air) batteries have recently sparked significant research interest in battery technologies due to their high theoretical energy densities, 5–10 times higher than commercial Li-ion batteries. These cells, however, have several major flaws, such as electrode disintegration, a short cycle life, polarization losses, and air sensitivity, which prevents them from dominating the battery field. The most important challenge is to develop a high-throughput air-breathing cathode capable of delivering effective oxygen while excluding other contaminants (e.g., CO2 and H2O), so that ambient air can be used for intake. Here, we developed nano-engineered metal oxide-graphene aerogel matrix composites (NMOGAM), as active air breathing cathodes, specifically embedded with nanowires (Fe2O3) along with nanoparticles (TiO2, dolomite CaMg(CO3)2)), to enhance CO2 capture along with inner hydrophobic groups that remove water. As a result, rechargeable high-performance Li-air batteries with high electrochemical performances (up to 500 cycles in air with a capacity of 5850 mAh g−1) are developed, which can be charged with a simple blow/puff of air.

Solid Phase Fusion: A Simple and Eco-Friendly Modification Strategy for Li1.2Ni0.2Mn0.6O2Li-Rich Cathode Materials

Li-rich cathode materials, with promising specific capacity, have attracted continued research attention. However, when charged to a high voltage, the materials experience rapid capacity decline and transition metal ion dissolution over the long cycle of the battery. In this work, fast ion conductor modified Li[Li0.2Ni0.2Mn0.6]O2(LLNM), as a Li-rich cathode material, has been effectively synthesized by the solid phase fusion technology (SFT). Typically, the structural transformation, metal ion dissolution and interface side reactions with the electrolyte are efficiently suppressed by the NaNbO3modified layer. The modified cathode materials exhibit optimal cycling stability with an initial discharge capacity of 186.8 mA h g−1and merely 0.22 V voltage fading after 200 cycles at 1 C. And this material shows better high and low temperature electrochemical performances. Moreover, SFT is an eco-friendly method, which is suitable for large scale synthesis, and shows good commercial perspective.

Facile preparation of SnO2/MoS2 nanocomposites with high electrochemical performance for energy storage applications

• SnO 2 /MoS 2 nanocomposite was synthesized by Sonochemical method. • The crystallite size of SnO 2 /MoS 2 nanocomposites was reduced while increasing the percentage of MoS 2 . • The FESEM images confirm the spherical morphology of SnO 2 and flake-like morphology of MoS 2 . • SnO 2 /MoS 2 (5 wt%) nanocomposite exhibited higher specific capacitance of 146F/g at a current density of 1 A/g. • High specific capacitance of composite is due to the synergetic effect of SnO 2 and MoS 2 . In this article, the pristine SnO 2 nanoparticles and MoS 2 nanoflakes were synthesized by the hydrothermal method. SnO 2 /MoS 2 nanocomposite is prepared by sonochemical method and the weight percent of MoS 2 is 1 %, 2 %, and 5 % in the composite. The Physicochemical properties such as the structural, morphological, optical properties, and functional groups of pristine SnO 2 and MoS 2 were analyzed and compared with SnO 2 /MoS 2 nanocomposites. XRD patterns confirmed the formation of cassiterite rutile SnO 2 with tetragonal structure. The lattice strain and crystallite size were calculated by Size-Strain plot method (SSP).The presence of functional groups was confirmed by FTIR analyses. The absorption and the bandgap of samples were found using the DRS UV–vis spectrum. Morphology, elemental composition, and particle size of the prepared samples were analyzed by FESEM, EDAX, and HRTEM. The BET analysis reveals the Surface area and pore volume of synthesized SnO2/MoS2 nanocomposite was relatively higher than the SnO 2 nanoparticles. The electrochemical performance of the prepared electrodes was evaluated by Chronopotentiometry (CP), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) analysis. The 5 % SnO 2 /MoS 2 composite electrode shows a maximum specific capacitance of 146F/g in a 2 M KOH electrolyte solution at a current density of 1 A/g.

Development of Si-C hybrid nanocomposite for Li-ion batteries with optimum silicon to polydopamine weight ratio

Different weight ratio of Si and polydopamine (PDA) has been employed for encapsulation of Si nanoparticles with PDA to buffer Si volume expansion and provide a pathway for Li ion transport. Si-C composite anodes have been developed and studied for Li-ion batteries (LIBs) by carrying out electrochemical characterization. The morphological properties of Si-C composites were also investigated. It was found that the 1:1Si to PDA weight ratio composite electrode led to high electrochemical performances. It delivered a high initial discharge capacity of 3451 mAhg−1 at 0.05C and retained greater capacity at higher C-rate compared to other composites.

All vanadium-based Li-ion hybrid supercapacitor with enhanced electrochemical performance via prelithiation

We report on the fabrication of an all-vanadium based Li-ion hybrid supercapacitor whose performance is highly enhanced compared to either batteries or supercapacitors via prelithiation process. Orthorhombic vanadium oxide nanoparticles and amorphous vanadium phosphate nanosheets implemented with carbon nanotubes are applied to battery-type and capacitive electrode, respectively. By utilizing vanadium-based electrodes with different charge-storage mechanisms in one device, advantages of both supercapacitors and batteries can be achieved. After a simple short-circuit prelithiation, the fabricated hybrid supercapacitor exhibits a high electrochemical performance with a capacitance of 111.6 F g−1 at 10 mA g−1, operation voltage window of 3.2 V, energy density of 160.2 Wh kg−1 and power density of 4.484 kW kg−1. Furthermore, it retains 98.3% of its initial capacitance after 2000 charge-discharge cycles. Due to its high operation voltage, a single, fully-charged hybrid supercapacitor successfully lights up variously colored LEDs for longer than one hr. With energy stored in the hybrid supercapacitor, a fragmentized graphene foam based strain sensor is powered to monitor various body-movements. This study demonstrates the high potential of the vanadium-based Li-ion hybrid supercapacitor as a powerful energy storage device obtained via deliberate selection of materials and prelithiation process.

Heteroatom doping strategy enables bi-functional electrode with superior electrochemical performance

As the fossil fuel consumption and energy shortage crisis worsen, it is urgent to develop multi-functional and cost-effective energy storage devices. However, the sluggish electrochemical kinetics of electrode materials is the major drawback which hinders their practical application. Herein, a heteroatom doped MnO2 carbon-based flexible electrode has been proposed derived from Ni2+ doping α-MnO2 by a facile hydrothermal strategy. Surprisingly, the as-prepared composite electrodes exhibit decent bi-functionally electrochemical performance both in lithium-ion batteries and aqueous supercapacitors. The superior performance of composite electrode is ascribed to high electrical conductivity, fast ionic diffusion rate, and the reduction of work function after the incorporation of Ni2+ ions based on the electrochemical kinetics analysis and density functional theory calculation. In summary, this work puts forward a facile strategy to construct high electrochemical performance electrode for lithium-ion batteries and aqueous supercapacitors.

Rechargeable aqueous zinc ion battery based on NaV6O15 nanorods by surfactant-assisted method

Vanadium oxides have a wide range of applications in aqueous zinc ion batteries due to their abundant resources and multiple valence states. However, the inherent low conductivity and structural instability of Vanadium-based materials often lead to the rapid degradation of their capacity. Consequently, stable microstructure and coordinated ion transport channels are essential to improve electrochemical performance. In this work, we report a surfactant-assisted hydrothermal method to obtain NaV6O15 with rod-like morphology and good dispersion. The surfactant-assisted NaV6O15 (NVO-I) electrode exhibited better cycle stability than the electrode without surfactant (NVO-II) during long cycles. The ordered morphology facilitated contact between the electrode and electrolyte, so the NVO-I electrode showed high electrochemical performance. The reversible capacity was 290.2 mAh g−1 at 0.1 A g−1, and the capacity retention was 95 % after 900 cycles at 1.0 A g−1. The surfactant-assisted hydrothermal strategy provides more options for developing stable and efficient AZIBs than other techniques.

Constructing methyl methacrylate/MXene artificial solid-electrolyte interphase layer for lithium metal batteries with high electrochemical performance

Lithium metal is a promising anode material due to its high theoretical capacity and low redox potential. However, lithium metal anode suffers from lithium dendrite, which reduces the cycle stability and reversibility of lithium metal batteries (LMBs). In order to solve this issue, we designed an in-situ polymerization method of organic–inorganic composite materials (methyl methacrylate (MMA)/MXene) to prepare artificial solid-electrolyte interphase (SEI). The as-prepared LMBs exhibit good interfacial contact and high electrochemical performance owing to the charge redistribution effect of MXene layer for decreasing the nucleation energy barrier and on the lithium metal anode. The specific capacity can sustain 106.6 mAh/g even after 1000 h cycles at 1C, and the capacity retention is 80.1 % with LiFePO4 (LFP) as a cathode material. Therefore, we believe this simple and inexpensive method can effectively restrain the growth of lithium dendrites and improve the cyclic stability and reversibility of the LMBs.

Hierarchical core-shell polypyrrole@NiCo layered double hydroxide arrays grown on stainless steel yarn with high flexibility for 1D symmetric yarn-shaped supercapacitors

A great deal of attention has been paid to flexible energy storage devices in recent years, but it remains a challenge to obtain integratable 1D energy storage devices with high specific capacitance and mechanical flexibility that can operate normally under common extrusion, bending, and tensile deformations. Herein, a flexible 1D yarn-shaped supercapacitor (YSC) was constructed based on Polypyrrole (PPy) @NiCo-layered double hydroxide (LDH) @stainless steel yarn (SSY) electrode prepared by facile hydrothermal and electrochemical deposition method. The as-obtained PPy@NiCo-LDH@SSY electrode exhibited an enhanced specific capacitance of 1196 F g−1 at 1 A g−1, owing to the synergistic impact of electroactive materials as well as the stratified core-shell structure. The electrospun separator automatically ensured the regular operation of the YSC device throughout use. Moreover, the YSC exhibited an energy density of 6.6 mWh cm−3 at the power density of 159.2 mW cm−3 and outstanding cycle performance (about 85.7% after 10 000 cycles). In addition, the YSC still maintained high electrochemical performance under different bending angles. The low cost, excellent overall performance and scalability make YSC a promising flexible wearable energy storage device.

Recent Progress on Graphene-Based Nanocomposites for Electrochemical Sodium-Ion Storage.

In advancing battery technologies, primary attention is paid to developing and optimizing low-cost electrode materials capable of fast reversible ion insertion and extraction with good cycling ability. Sodium-ion batteries stand out due to their inexpensive price and comparable operating principle to lithium-ion batteries. To achieve this target, various graphene-based nanocomposites fabricate strategies have been proposed to help realize the nanostructured electrode for high electrochemical performance sodium-ion batteries. In this review, the graphene-based nanocomposites were introduced according to the following main categories: graphene surface modification and doping, three-dimensional structured graphene, graphene coated on the surface of active materials, and the intercalation layer stacked graphene. Through one or more of the above strategies, graphene is compounded with active substances to prepare the nanocomposite electrode, which is applied as the anode or cathode to sodium-ion batteries. The recent research progress of graphene-based nanocomposites for SIBs is also summarized in this study based on the above categories, especially for nanocomposite fabricate methods, the structural characteristics of electrodes as well as the influence of graphene on the performance of the SIBs. In addition, the relevant mechanism is also within the scope of this discussion, such as synergistic effect of graphene with active substances, the insertion/deintercalation process of sodium ions in different kinds of nanocomposites, and electrochemical reaction mechanism in the energy storage. At the end of this study, a series of strategies are summarized to address the challenges of graphene-based nanocomposites and several critical research prospects of SIBs that provide insights for future investigations.

Metal-organic frameworks (MOFs)-derived Co3O4@N-doped carbon as an electrode materials for supercapacitor

Pyrolysis of cobalt (Co)-based metal-organic frameworks (MOF) was used to synthesize Co3O4@N-doped C composites. The hierarchical porous structure of zeolitic imidazolate frameworks (ZIF-67) was synthesized using a triethylamine-assisted method in water and room temperature. ZIF-67 was used as a precursor for the synthesis of Co3O4@N-doped C. The material was characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), and X-ray photoelectron microscope (XPS). The carbon content and hierarchical porous structure of ZIF-67 enhanced the electron and ion transport. As a result of these advantages, the Co3O4@N-doped C electrode demonstrated improved capacitive performance, with a high specific capacitance of 709 F g−1 at 1 A g−1 and a reasonable rate capability after 5000 cycles. The simple synthesis procedure and the high electrochemical performance enable promising electroactive materials for supercapacitors using MOF-derived materials.

In-situ growth of NiAl layered double hydroxides on Ni-based metal-organic framework derived hierarchical carbon as high performance material for Zn-ion batteries

The development of advanced active materials with high capacity, low-cost, and safety has become a requirement to meet future energy storage systems for electric vehicles. Herein, we report a rational in-situ synthesis of NiAl layered double hydroxides (LDHs) on Ni-based metal-organic framework (MOF)-derived porous carbons (PCs) material (NiAl-LDH/Ni@C) with cross-linking nanosheet structure and high electrical conductivity by a hydrothermal method. This unique structure design improves electrical conductivity, reduces internal resistance, and enables more electrochemically active sites to participate in chemical reactions through the strong interaction and synergy between the hierarchical structure of two-dimensional nanosheets and PCs. The results exhibit that NiAl-LDH/Ni@C composite possesses a large specific capacity (391.7 mAh g−1), high rate capability, and outstanding capacity retention stability (97.6%@10 A g−1 after 10,000 cycles). Furthermore, the as-assembled Zn-ion battery based on a NiAl-LDH/Ni@C cathode displays a remarkable capacity (345 mAh g−1@1 A g−1), excellent energy/power density (604.6 Wh kg−1/1.77 kW kg−1), and superb cycle durability (95.3%@2 A g−1). The proposed approach provides an unprecedented direction for designing advanced energy storage devices with high electrochemical performance.

Study on flexible thin air electrodes and electrochemical performance of LR6 size as well as pouch Zn-air cells

Manufacturing stable and thin air electrodes for flexible Zn-air batteries becomes increasingly important and remains challenge. Here, we report low-cost mechanical calendering to fabricate thin gas-diffusion layers (GDL), catalytic layers (CL) and then heat pressing together. Finally, cylindrical and other sizes of flexible air electrodes are produced without the use of commercially expensive carbon cloth or carbon papers. By assembling the flexible air cathodes with anode Zn-In-Bi alloy powders or Zn foils, alkaline gel electrolytes and membranes, two kinds of Zn-air cells are assembled for performance evaluation. Results reveal that the LR6 Zn-air cells show a capacity of 5300–5400 mAh and an energy density of 340 Wh·kg−1 at 100 mA, having a double discharge capacity compared to the same size alkaline ZnMnO2 cells. Under a high drain rate of 1000 mA, the capacity and utilization of the Zn alloy powder remain 2750 mAh and 372 mAh·g−1, respectively. The flexible pouch Zn-air cells exhibit excellent charge-discharge performance under conditions of each cycle with 10 min at 2 mA cm−2. The discharge voltage is maintained in the range of 1.25–1.30 V within 120 cycles while the charge voltage is 2.00–2.05 V. These results demonstrate that the thin air cathodes can satisfy the high bending requirements for cylindrical LR6 size cells and flexible pouch Zn-air cells, as well as have high mechanical stability and electrochemical performance. Electrochemical impedance spectroscopies of the air cathodes and Zn-air cells are also examined.

Covalent organic frameworks (COFs)-derived nitrogen-doped carbon/reduced graphene oxide nanocomposite as electrodes materials for supercapacitors

This study reports the ex-situ and in-situ (one-pot) synthesis of a triazine covalent organic framework (COF)/graphene oxide (GO) nanocomposite. The materials are used to synthesize N-doped carbon (N-doped C)/reduced GO (rGO) via a simple carbonization step. The nanocomposites are used as electrode materials for supercapacitors. N-doped C/rGO synthesized via the in-situ method exhibits good electrochemical performance compared to the materials synthesized via the ex-situ procedure. N-doped C/rGO_In-situ offers a specific capacitance of 234 F·g−1 at the current density of 0.8 A·g−1. Two symmetric supercapacitor devices illuminate a white light-emitting diode (LED) lamp. A device using an N-doped C/rGO_In situ electrode shows high specific energy of 14.6 W·h·kg−1 and high specific power of 400 W·kg−1, with only a 14 % decrease in the capacitance performance after 3500 cycles. The simple synthesis procedure using the in-situ method and the high electrochemical performance of the synthesized materials may advance the exploration of an effective electrode material for supercapacitors.