High-performance Asymmetric Supercapacitors Research Articles

High-performance aqueous asymmetric supercapacitors based on K+ and Na+ co-preinserted δ-MnO2 nanocrystals

High-performance aqueous asymmetric supercapacitors based on K+ and Na+ co-preinserted δ-MnO2 nanocrystals

Self-supporting NiO-coated activated carbon nanofibers based on atomic layer deposition for supercapacitor

The rapid development of consumer electronics, electric vehicles, and smart meters demands high-performance energy storage devices. By now, supercapacitors are expected to become one of the most promising energy devices for future energy technology. In this work, NiO nanoparticles supported on activated carbon nanofibers (NiO/ACNFs) have been synthesized by atomic layer deposition technique, which is directly used as self-supporting binder-free electrodes for supercapacitors. Scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman results show that NiO nanoparticles (3.1 nm) are uniformly coated on ACNFs. The NiO/ACNFs-600 electrodes demonstrate a specific capacitance of 870 F·g−1 (1 A·g−1) and good rate capability (remain 67% at 10 A·g−1). The asymmetric supercapacitor devices with NiO/ACNFs-600//ACNFs electrodes yield a fairly high energy density of 39.85 Wh·kg−1 at 2000 W·kg−1 and excellent capacitance retention of 87% after 10,000 cycles. The excellent electrochemical capacitance performance for NiO/ACNFs is attributed to the high conductivity and large specific surface area of ACNFs, high capacity, small size, and even dispersion of NiO as well as the synergistic effect between them. These results demonstrate that NiO/ACNFs can serve as excellent electrode materials for high-performance asymmetric supercapacitors.

Rational construction of NiCo double-hydroxide/cobalt hydroxycarbonate as advanced electrode for high performance asymmetric supercapacitor

In this present paper, a novel nickel‑cobalt double hydroxide/cobalt carbonate hydroxide nanosheets composite (NiCo-DH/NSs) with excellent electrochemical performances is successfully constructed through a rational design of the structure and composition. Cobalt carbonate hydroxide (Co2(OH)2CO3) with a nanosheet morphology and low surface energy is firstly prepared by an simple one-step hydrothermal approach. Then the electroconductive NSs are exploited as a substrate for the in-situ growth of metal-organic framework (MOF). The pre-synthesized MOF/NSs composite is further alkali treated to obtain the final composite material by a “crystal-crystal conversion” strategy. Due to proper structure and synergistic effect between two components, the prepared NiCo-DH/NSs as positive electrode material delivers a high specific capacity (586 mAh g−1 at 1 A g−1) and outstanding rate performance (92.15 % capacity retention at 10 A g−1). In addition, a high specific capacitance of negative electrode material (BiOBr microsphere) is also successfully prepared. As a result, the assembled NiCo-DH/NSs//BiOBr asymmetric supercapacitor (ASC) device exhibits ultrahigh energy density of 67.74 Wh kg−1 at power density of 775.03 W kg−1.

Hybrid nanostructures made of porous binary transition metal oxides for high performance asymmetric supercapacitor application

The present work is an experimental comparison of various binary transition metal oxides (BTMOs) and their application as electrode material for supercapaitor (SC). The possibility of Molybdenum oxides and their nanostructures are explored in the field of energy storage devices however, very few works have been reported analyzing the potential of BTMOs as electrode materials for energy applications. Herein, CoMoO4, NiMoO4, MnMoO4 and CuMoO4 nanostructures were synthesized and implicated as an electrode for coin-cell based SC. The electrode materials were tested in both three and two-electrode system to conclude the suitable electrode for commercial application. Coin-cell device based on XMoO4║NrGO/CNT was fabricated and compared in this study. This comparative experimental study investigated the influence of the intrinsic properties of electrodes on specific capacitance. NiMoO4║NrGO/CNT delivered a capacitance of 261 F g−1 and capacity retention of 80 %. Also, depicted an energy density of 45.23 Wh kg−1 at a power density of 7500 W kg−1. This excellent electrochemical performance of the NiMoO4 electrode implies it will be a prospective candidate for supercapacitor application.

Carbon nitride mediated synthesis of titanium-based electrodes for high-performance asymmetric supercapacitors

Rational design of electrode materials with specific compositions and unique morphological and structural features to achieve supercapacitors (SCs) with high energy densities without compromising their inherent electrochemical merits remains a great challenge. Herein, a carbon nitride (C3N4) mediated “one-for-two” strategy was proposed to synthesize titanium nitride/carbon nanosheets (TiN/C) and titanium carbide/carbon nanosheets (TiC/C) with three-dimensional morphology and hierarchical structure, respectively. The derived TiN/C and TiC/C were used as cathode and anode materials, respectively, with excellent capacitor behavior in aqueous electrolyte. Specifically, asymmetric SCs constructed with the TiN/C cathode and the TiC/C anode delivered a large operation voltage of 0.3–1.8 V, a high specific capacitance of 103 F·g−1, and a remarkable energy density of 45.2 Wh·kg−1, outperforming most of the previously reported TiN- and TiC-based SCs. Ex situ XRD and TEM characterizations as well as DFT simulation indicated that the excellent performance could be attributed to reversible pseudocapacitive redox reaction and electro-adsorbed anions at the TiN/C cathode, and fast adsorption/desorption of cations at the TiC/C anode, as well as unique surface morphology and heterostructure. The strategy presented in this work also provides new design concepts for the synthesis of other transition metal nitrides (or carbides)/carbon composites for other advanced energy applications.

A pseudocapacitive molecule-induced strategy to construct flexible high-performance asymmetric supercapacitors

A pseudocapacitive molecule-induced strategy to construct flexible high-performance asymmetric supercapacitors

Facile in-situ grown spinel MnCo2O4/MWCNT and MnCo2O4/Ti3C2 MXene composites for high-performance asymmetric supercapacitor with theoretical insight

The logical construction of electrode materials along with greater electrochemical features and solid architectural design is a strategic approach for boosting the electrochemical performance of supercapacitors. However, it is tough and complicated to develop diverse composite materials with better electronic conductivity and greater specific capacitance via rapid and cost-effective synthesis procedures. Herein, we propose a straightforward and simple approach by employing the hydrothermal technique for the synthesis of spinel MnCo2O4 composite nanostructures using 1D MWCNT and 2D MXene (Ti3C2Tx) materials with detailed analysis of the supercapacitor performance as compared to existing literature on similar studies. The MCO/TCX (MnCo2O4/Ti3C2Tx) composite shows an impressive capacitance of 860.22 F/g at a current density of 2 A/g after electrochemical optimization. Furthermore, an asymmetric supercapacitor device (ASCs) was constructed using MCO and its composites MCO/MWCNT and MCO/TCX as a positive, and AC was employed as a negative electrode to test its device capability. Comparatively, the MCO/TCX//AC SC device demonstrated exceptional energy storage properties with a better specific capacitance value of 126.58 F/g at 0.8 A/g of current density, an elevated energy density of 40 Wh/kg, with a power density of 4828 W/kg along a capacitance retention rate of 87 % over 5000 cycles, suggesting better cycle life. Whereas, the MCO/MWCNT//AC device shows a better cycling performance of 91 % after 5000 cycles with a superior energy and power density of 27.04 Wh/kg and 1448 W/kg respectively. Also the theoretical insight for further understanding of the charge-storage mechanism through DFT calculations provides an estimate of electronic properties and quantum capacitance calculated for the pristine MCO and its hybrids with CNT and Ti3C2Tx MXene and information on the interactions between orbitals, the bonding process, and the charge transfer capabilities of each electrode material. The theoretical studies also confirm that the electronic properties and therein charge storage performance have an increasing trend in the order of MCO < MCO/CNT < MCO/TCX consistent with the experimental findings. Additionally, these simulations conclude that the hybrid MCO/TCX has the largest quantum capacitance which is in accordance with the findings of the experiments. The improved performance of MCO/TCX is due to the enlarged surface area that allows higher charge transfer from TCX to MCO. The charge transferred from the C 2p orbital of TCX to the Mn 3d orbital of MCO is the leading cause for the capacitance improvement mechanism of hybrid MCO/TCX. This work offers a simple procedure for developing energy storage devices using spinel MnCo2O4-based composite electrode materials supported by 1D carbon nanotube and 2D MXene that offer superior electrochemical performance and the fabricated electrodes that could be employed further for energy storage-based applications.

Ultrafine nanoparticles of tin-cobalt-sulfide decorated over 2D MXene sheets as a cathode material for high-performance asymmetric supercapacitor

The design of electrode materials for improved electrochemical properties and stable geometric configuration is known as effective research in developing the electrochemical capability of supercapacitors (SCs). However, there is a difficulty in designing innovative composite material with excellent electrical conductivity and superior specific capacity by way of low cost and easy synthesis process. Herein, for the first time, a stable Sn-Co-S/MXene hybrid material is fabricated through the electrochemical assembly by combining positively charged ultrafine Sn-Co-S nanoparticles (NPs) and negatively charged 2D Ti3C2Tx (MXene) sheets due to electrostatic interaction. The Sn-Co-S/MXene hybrid material has displayed excellent electrochemical performance with an ultrahigh specific capacity of 305.71 mA h gm−1 at 1 A g−1 and capacity retention of 94.8% after 10, 000 charge–discharge cycles. The Sn-Co-S/MXene hybrid material of high electrochemical performance has improved charge transfer kinetics during the charge–discharge process, due to the synergistic coupling effect between ultrafine Sn-Co-S nanoparticles and MXene sheets. Furthermore, the Sn-Co-S/MXene//activated carbon (AC) asymmetric supercapacitor (ASC) device has been configured with the assistance of Sn-Co-S/MXene as cathode and AC as anode materials. The Sn-Co-S/MXene//AC ASC device exhibits a stable potential window of 1.7 V, a high specific capacitance of 108.50F g−1 at 1 A g−1, and an energy density of 43.55Wh kg−1 at a power density of 0.83 kW kg−1. This study validates the design and application of highly electroactive Sn-Co-S/MXene hybrid electrode material for ultrastable asymmetric supercapacitors.

A Cobalt-Based Metal-Organic Framework Nanosheet as the Electrode for High-Performance Asymmetric Supercapacitor.

Inspired by the significant advantages of the bottom-up synthesis whose structures and functionalities can be customized by the selection of molecular components, a 2D metal-organic framework (MOF) nanosheet Co-BTB-LB has been synthesized by a liquid-liquid interface-assisted method. The as-prepared Co-BTB-LB is identified by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX) and X-ray photoelectron spectroscopy (XPS), and the sheet-like structure is verified by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and atomic force microscopy (AFM). Co-BTB-LB electrode exhibits an excellent capacity of 4969.3Fg-1 at 1Ag-1 and good cycling stability with 75% capacity retention after 1000 cycles. The asymmetric supercapacitor device with Co-BTB-LB as the positive electrode shows a maximum energy density of 150.2Whkg-1 at a power density of 1619.2Wkg-1 and good cycling stability with a capacitance retention of 97.1% after 10000 cycles. This represents a state-of-the-art performance reported for asymmetric supercapacitor device using electroactive bottom-up metal-complex nanosheet, which will clearly lead to a significant expansion of the applicability of this type of 2D nanomaterials.

One pot synthesis of carbon decorated NiO nanorods as cathode materials for high-performance asymmetric supercapacitors

The composites of metal oxides and carbons are of research interest for improving the energy density of supercapacitors. In this work, we have demonstrated a simple one-pot hydrothermal synthesis method to prepare NiO nanorods followed by carbon framework decorated NiO nanorods (NiO@C). The NiO@C electrode showed an excellent specific capacitance of 1360 F g−1 compared to pristine NiO of 890 F g−1 at 1 A g−1 in a voltage range of 0.05 to 0.5 V in 1 M KOH electrolyte. The NiO@C electrodes showed excellent cycle stability over 10,000 cycles with 90 % capacitance retention. Asymmetric supercapacitors fabricated using corncob-derived activated carbon anode, and NiO@C cathode delivers a power density of 4574 W kg−1 at an energy density of 21.6 Wh kg−1. The enhanced capacitance of NiO@C material is due to the synergistic effect of the pseudocapacitive of NiO nanorods and the electric double-layer capacitance of the carbon matrix. Besides, the carbon framework facilitates quick charge acceptance, improved cycling stability, and rate capability. The cost-effective one-pot synthesis and eco-friendly NiO nanorods with easy electrode fabrication open opportunities for developing high-energy-density NiO-based supercapacitors.

A novel MoP2@Ni2P nanosheet and an individual kelp-based porous carbon for assembly a unique high performance asymmetric supercapacitor

In order to improve the specific capacity and energy density of the asymmetric supercapacitors, it is necessary to design positive and negative electrode materials with special structure and good electrochemical properties. Herein, a novel MoP2@Ni2P nanosheet material is prepared by one-step simple hydrothermal synthesis and low temperature phosphating method, which exhibits excellent specific capacity of 133.6 mAh g−1 at 0.5 A g−1. In addition, a kelp based porous carbon nanosheet material (AKPC) is prepared via swollen the kelp in a sodium chloride solution and then subjected to an activation and carbonization. Because of its biomaterial unique morphology, the carbon material shows ultra-high specific surface area (1197 m2 g−1) and large pore volume, thus possess a high specific capacitance of 180 F g−1 at 0.5 A g−1. Moreover, the above two materials are assembled into a unique asymmetric supercapacitor with operating voltage of 1.65 V, which has demonstrated a high energy density of 31.5 Wh kg−1 and excellent cycling stability with 81 % capacitance retention after 1500 cycles in aqueous electrolyte. The successful preparation of the asymmetric device provides a new idea for the development of high performance electronic devices.

Unique hierarchical architecture of SnO2 hexagonal interconnected nanolayered arrays as negative electrode for high performance asymmetric supercapacitors

In this research, we report unique hierarchical structures of SnO2 hexagonal interconnected nanolayered arrays (HINLA) fabricated on the carbon cloth (SnO2 HINLA@CC) by a facile electrochemical deposition technique. The structural, morphological evolution and electrochemical properties of as prepared SnO2 HINLA@CC are explored as negative electrode of SCs. SnO2 HINLA@CC has been tested in negative potential widow of −1.0-0 V and demonstrated the high specific capacitance of 325 F g−1 at 1 A g−1, much superior when compared to the previously reported data for SnO2. The EIS analysis confirmed the charge transfer kinetics of SnO2 HINLA@CC, with significant stability due to favorable morphology for swift response. Capacitance retention plot confirmed no structural degradation or pulverization for negative electrode even after 5000 galvanostatic charge with 88.6% capacitance retention. Such high performances of SnO2 HINLA@CC as negative electrode make it an ideal candidate to be useful in ASCs. Moreover, a 2.2 V aqueous ASC has been constructed by employing Na0·5MnO2 nanowall arrays (NWAs) as cathode and SnO2 HINLA@CC as anode. In particular, the 2.2 V Na0·5MnO2 NWAs@CC//SnO2 HINLA@CC ASC has demonstrated the superior energy density of ∼73 Wh kg−1, significant rate capability and excellent cycling ability, outperforming the previously reported SnO2-based ASCs. Present work provides new opportunities for developing promising high-voltage aqueous ASCs with excellent energy density.

MOF derived NiCo2O4 nanosheets for high performance asymmetric supercapacitor

The electrochemical performance of the faradaic battery-type metal oxide electrodes is dependent on the calcination temperature. Herein, we report metal–organic framework (MOF) derived bimetallic oxide (NiCo2O4-MOF) electrode materials for high-performance supercapacitor (SC) applications. Remarkably, the optimal NCM electrode with the annealing temperature 300 °C (NCM-300) achieves the maximum specific capacity of 188 mAh/g at 5 Ag−1 and the excellent rate capability of 85.25% after 3000 cycles, far exceeding those of their single counterpart. Interestingly, designed asymmetric device (ASC) using NiCo2O4-MOF (positive electrode) and activated carbon (AC) (negative electrode) showed excellent energy density 84.26 Wh kg−1 at a power density of 1185 W kg−1 with 83.23% capacitance retention after 10,000 cycles. This report illustrates a novel route for synthesis and fabrication of metal oxides derived MOF having a large porosity which is beneficial to the electrochemical energy storage applications.

Pre-activation strategy of α-MnO2 electrode to construct high-performance asymmetric sodium-ion supercapacitors

Aqueous asymmetric sodium-ion supercapacitors (ASSCs) with high energy density assembled from all-inorganic materials are expected to provide high-efficiency power sources for intelligent electric vehicles and off-grid systems. However, it is still challenging to fabricate high-performance positive materials by a simple method and rationally assemble ASSCs to meet the demand of ultralong cycle life and high energy/power density. Here, a simple pre-activation strategy was introduced into the α-MnO2 electrode with a microcrystalline nanosheet structure to improve the Na-storage performance. The sodium-ions concentration was optimized by tuning charge-discharge parameters. Impressively, the pre-activated electrode achieved superior capacitance retention after 10,000 cycles, high volumetric capacitance of 377 F cm−3 and low charge transfer resistance of 5.9 Ω. Based on the facile operability of the proposed pre-activation strategy, it can be expected to be easily ported to other Li/K/Zn-storage, providing a novel avenue for the exploration of positive electrode materials with outstanding electrochemical behaviors. A novel ASSC was fabricated by matching α-MnO2//WO3 electrodes, exhibiting wide voltage of 2.0 V, high energy/power density (0.965 W h cm−3/65.2 W cm−3) and ultralong cycle life. This work proposes a simple strategy to develop high-performance positive materials and assemble ASSC with high energy/power density and long-term stable operation.

Synergistic effect of carbon nanotube and tri-metallic MOF nanoarchitecture for electrochemical high-performance asymmetric supercapacitor applications and their charge storage mechanism

To develop innovative energy-storage devices, metal-organic frameworks (MOFs) with various nano-geometries must be rationally combined. In this research, a trimetallic-based MOF with varying ratios of carbon nanotubes (CNT) was synthesized and optimized for use in electrochemical supercapacitor devices. The composite material has a corrugated-layered structure that allows for fast ion transport and electrolyte storage. The synergistic features of CNT and MOF, along with the stronger redox reactions of multimetallic ionic species, enable effective charge storage. The 1D nanotube form of CNT provides stability and electrical conductivity. MOF-CNT(5 %) showed a higher capacitive efficiency than MOF due to its high specific capacitance and rate capacity (86.1 % retention at 5 A/g). The MOF-CNT(5 %)//ACarbon composite exhibited a capacitance of 166.4 F/g at 1 A/g, 79.2 % retention after 10,000 charging/discharging cycles, a high-power density of 501.5 W/kg, and an energy density of 23.6 Wh/kg, making it a potential nanomaterial for asymmetric supercapacitors. Dunn's and Trasatti's model were used to extract regression parameters and capacitive-diffusive contributions of the supercapacitor.

Synergetic effect of ternary MnVMo-oxide electrode by hydrothermal method for high-performance asymmetric supercapacitor

The binder-free deposition facilitates fast electron transfer and smoothens the diffusion path of electrolyte ions into the matrix of electrode material. Herein, the ternary metal oxides, such as manganese vanadium molybdenum oxide (MnVMo-oxide) is directly deposited on nickel foam by a single-step hydrothermal method. X-ray diffraction study confirms formation of MnVMo-oxide phase. The X-ray photoelectron spectroscopy confirms the Mn, V, and Mo are in the +2 (and +3), +5, and +6 oxidation states. Deposition time variation results, change in nanostructures from nanoparticle-assembled sheets to rectangular nanosheets, also the size of micro rods. The porous microrods formed with uneven quasi-rectangular shaped nanosheets of MnVMo-oxide exhibit high areal capacitance of 814.5 mFcm−2 (as compared to other electrodes) measured in 1 M KOH electrolyte at 3 mAcm−2 current density. The enhanced capacitance of the MnVMo-8 electrode is due to the dominance of the diffusion process over the capacitive-controlled contribution and high diffusion coefficient. The fabricated asymmetric supercapacitor device MnVMo-oxide//activated carbon shows good areal capacitance of 40 mFcm−2 with 0.025 mWhcm−2 energy at 1.5 mWcm−2 power density measured at 2 mAcm−2 current density, and cyclic stability of about 71.45 % (Coulombic efficiency of 98 %) quantified up to ∼9000 consecutive cycles.

Preparation of MoFs-Derived Cobalt Oxide/Carbon Nanotubes Composites for High-Performance Asymmetric Supercapacitor

Metal-organic frameworks (MOFs)-derived metallic oxide compounds exhibit a tunable structure and intriguing activity and have received intensive investigation in recent years. Herein, this work reports metal-organic frameworks (MOFs)-derived cobalt oxide/carbon nanotubes (MWCNTx@Co3O4) composites by calcining the MWCNTx@ZIF-67 precursor in one step. The morphology and structure of the composite were investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM) characterization. The compositions and valence states of the compounds were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Benefiting from the structurally stable MOFs-derived porous cobalt oxide frameworks and the homogeneous conductive carbon nanotubes, the synthesized MWCNTx@Co3O4 composites display a maximum specific capacitance of 206.89 F·g-1 at 1.0 A·g-1. In addition, the specific capacitance of the MWCNT3@Co3O4//activated carbon (AC) asymmetric capacitor reaches 50 F·g-1, and has an excellent electrochemical performance. These results suggest that the MWCNTx@Co3O4 composites can be a potential candidate for electrochemical energy storage devices.

ZIF-9 derived rGO/NiCo2S4 composite as the electrode materials for high performance asymmetric supercapacitor

Transition metal sulfide is considered as one of the best materials for high-performance supercapacitors because of its excellent conductivity, high theoretical specific capacitance and good thermal stability. Herein, the reduction graphene oxide supported NiCo2S4 (rGO/NiCo2S4) nanomaterial was successfully fabricated at ambient temperature via a facile strategy. Three-dimensional ZIF-9 was used as a tem-plate, graphene oxide was used as the supporting material and Ni(NO3)2 was used as both etchant and Nickel source. As a result, the prepared materials shows a high specific capacitance of 1242.2 F g−1 at a current density of 1 A g−1. Besides, the assembled active carbon (AC)//rGO/NiCo2S4 asymmetric supercapacitor delivered a high energy density of 79.87 Wh kg−1 with a power density of 750 W kg−1 and a capacity retention of 58.5% after 5000 cycles. This work demonstrates an simple design pathway to manufacture bimetallic sulfide and provides basic research for the application of bimetallic sulfide with high surface area and high electrochemical activity used in supercapacitors.

Fabrication of activated carbon coated MSe2 (M=Mo, Co, and Ni) nanocomposite electrode for high-performance aqueous asymmetric supercapacitor

Transition metal diselenides are trendy electrode materials for supercapacitors. The main reason behind it is their high specific capacitance. But, they suffer from poor electronic conductivity and agglomeration issues which hinder their practical use. Herein, we present the preparation of nanocomposites including transition metal diselenide MSe2 (M=Mo, Co, and Ni) with activated carbon using the facial hydrothermal route. Inspiring from the high electrochemical results of a hybrid nanocomposites symmetric cell, an aqueous asymmetric ultracapacitor cell (AUC) comprised of different shaped carbon-coated MSe2 (positive electrode) as well as activated carbon (AC) (negative electrode) has been fabricated. The NAC//6KOH//AC asymmetric cell displays the best outcomes among all fabricated devices. The specific capacitance observed is about 3740 F g−1 at 10 mV s−1. It delivers a high energy density of 69 Wh kg−1 along with a power density of 687 W kg−1 at 1 A g−1. The electrochemical results motivate us to explore the practical usability of the prepared NAC//6KOH//AC device via illuminating 26 red LED panels which glow for 26 min. The findings in this report indicate that MSe2-based nanocomposite has the scope and is a potential material in the energy storage field.

Heterostructure of MnSe2@NiCo2Se4 as novel electrode material for high-performance asymmetric supercapacitors

For high-performance electrochemical energy storage and conversion applications, controllable nanoarchitecture arrays of the transition metal selenide on conductive substrates are attractive electrode materials. In this work, a heterostructure comprising of MnSe2 nanorods over NiCo2Se4 nanosheets with a large specific surface area is rationally generated on nickel foam (NF) substrate (MnSe2@NiCo2Se4) using a hydrothermal process. The formation mechanism of the MnSe2@NiCo2Se4 heterostructure was also examined by adjusting the selenium feeding during the selenization process. The MnSe2@NiCo2Se4-2 electrode exhibits remarkable capacitance (1078C g−1 at 1 A g−1), and superior cycle stability (90.7 % after 8000 cycles) as a result of the cooperative effect of MnSe2 and NiCo2Se4. Furthermore, an asymmetric supercapacitor (ASC) was developed employing the improved MnSe2@NiCo2Se4-2 and activated carbon materials (AC) as the positive electrode and negative electrode (MnSe2@NiCo2Se4-2//AC), respectively, which has a high energy density of 63.2 Wh kg−1 at a power density of 396 W kg−1. The impressive performance indicates that the MnSe2@NiCo2Se4 electrode has a bright potential in supercapacitors.