Core-shell structured ZIF-7@ZIF-67 with high electrochemical performance for all-solid-state asymmetric supercapacitor

Zeolitic imidazolate frameworks (ZIFs) are considered as a promising material for energy storage in recent years. Here, core-shell structured ZIF-7@ZIF-67 is synthesized in this work. The core-shell structured material can promote electron transfer of inner-outer metals ions of ZIF-7@ZIF-67, quicken diffusion of electrolyte ions and improve the capacitance performance compared to the ZIF-7 and ZIF-67. ZIF-7@ZIF-67 delivers good energy storage ability with a specific capacitance of 518.9 F g⁻¹ at a current density of 1 A g⁻¹ and remarkable stability with a retention of 99.6% after 4000 cycles in the three-electrode system. Furthermore, an all-solid-state asymmetric supercapacitor (ASC) device is assembled based on core-shell structured ZIF-7@ZIF-67 as positive electrode. Impressively, the ASC device displays an energy density of 31 Wh kg⁻¹ at a power density of 400 W kg⁻¹ and an excellent cyclic stability with 99.5% retention after 10,000 cycles at a current density of 10 A g⁻¹. Finally, two all-solid-state ASCs are contacted to power various lighting-emitting diodes (LED). The red LED can be kept glowing for over 10 min. These electrochemical characteristics suggest that core-shell structured ZIF-7@ZIF-67 is a potential material for energy storage device with long-life cyclic stability.     

One-step hydrothermal preparation of bi-functional NiS2/reduced graphene oxide composite electrode material for dye-sensitized solar cells and supercapacitors

To screen out suitable electrode materials and overcome the shortcomings of the existed electrode materials for the application in dye-sensitized solar cells and supercapacitors, NiS₂/reduced graphene oxide (NiS₂/rGO) composite material was prepared by a simple one-step hydrothermal method in this paper and applied in the field of both dye-sensitized solar cells and supercapacitors as electrode material. In an electrolyte of 6 M KOH, the NiS₂/rGO composite material with bilayer capacitance characteristics exhibited a high specific capacitance of 259.20 F g⁻¹ at the current density of 0.6 A g⁻¹, which was significantly higher than that of rGO (188.94 F g⁻¹). Moreover, at a current density of 2 A g⁻¹, the NiS₂/rGO composite material had 92.85% capacitance retention after 2000 cycles. When applied as counter electrode material for the dye-sensitized solar cells, the NiS₂/rGO composite material counter electrode exhibited a satisfactory photoelectric conversion efficiency (η) of 3.16% under standard simulated sunlight (AM 1.5 G), which was significantly higher than that of single rGO counter electrode (improved by 90.40%). The NiS₂/rGO composite electrode material prepared by a simple one-step hydrothermal method is a potential bi-functional composite electrode materials for both dye-sensitized solar cells and supercapacitors.     

Yuba-like porous carbon microrods derived from celosia cristata for high-performance supercapacitors and efficient oxygen reduction electrocatalysts

Here, a novel yuba-like porous carbon microrod is prepared via a simple and facile strategy by using the fluffy fibers of celosia cristata petals (FCCP) as the raw material. The optimized carbon microrod (FCCP-CM-900) possesses unique yuba-like structure, high specific surface area (1680 m² g⁻¹) and large pore volume (0.98 cm³ g⁻¹), and effective nitrogen (∼4.52 at.%) and oxygen (∼5.49 at.%) doping, which can enhance the wettability and conductivity (7.9 S cm⁻¹). As the electrode material for supercapacitor, FCCP-CM-900-based supercapacitor presents high specific capacitance (314.5 F g⁻¹ at 0.5 A g⁻¹) in 6.0 M KOH aqueous electrolyte. The FCCP-CM-900-based symmetrical supercapacitor displays high energy density (18.6 Wh kg⁻¹ at 233.4 W kg⁻¹) and outstanding cycling stability (98% capacitance retention after 10,000 cycles) in 1.0 M Na₂SO₄ electrolyte. In addition, served as oxygen reduction electrocatalyst, the FCCP-CM-900 also exhibits excellent catalytic activity, good durability, together with high methanol tolerance in alkaline electrolyte, which makes it a highly efficient air cathode material toward zinc–air cell.     

Fabrication of CoFe/N-doped mesoporous carbon hybrids from Prussian blue analogous as high performance cathodes for lithium-sulfur batteries

CoFe/N-doped mesoporous carbon hybrids are synthesized by a simple pyrolysis of Prussian blue analogue (PBA) and melamine, in which the structure is rationally designed by controlling the weight ratio of PBA/melamine and annealing temperature. By applying the composite as the cathode material for lithium-sulfur batteries, it demonstrates outstanding electrochemical performances including a high reversible capacity (1315 mAh g⁻¹ at 0.2 C), excellent rate capability (724 and 496 mAh g⁻¹ at 2 and 5 C rates, respectively) and superior cycling stability (528 and 367 mAh g⁻¹ at 2 and 5C after 500 cycles, respectively). The synergetic effect of the mesoporous carbon matrix, uniform sized CoFe nanoparticles and N heteroatoms simultaneously contributes to the confinement of sulfur species. The presence of abundant mesopores and micropores can physically confine sulfur species. The formed CoFe-N_x moieties can not only improve the electronic conductivity of the as-prepared composites, but also offer highly effective active sites for chemical absorption and catalytic transformation of polysulfides to suppress any shuttle effect. In addition, the mesoporous structure can effectively alleviate the volume changes resulted from charge–discharge process. The strategy developed in this work proposes an alternative way to obtain N-doped mesoporous carbon matrix modified with CoFe nanoparticles for high performance cathode materials of lithium-sulfur batteries.     

Rational design of hierarchical core-shell structured CoMoO4@CoS composites on reduced graphene oxide for supercapacitors with enhanced electrochemical performance

Engineering multicomponent active materials as an advanced electrode with the rational designed core-shell structure is an effective way to enhance the electrochemical performances for supercapacitors. Herein, three-dimensional self-supported hierarchical CoMoO₄@CoS core-shell heterostructures supported on reduced graphene oxide/Ni foam have been rationally designed and prepared via a facile approach. The unique structure and the synergistic effects between two different materials, as well as excellent electronic conductivity of the reduced graphene oxide, contribute to the increased electrochemically active site and enhanced capacitance. The core-shell CoMoO₄@CoS composite displays the superior specific capacitance of 3380.3 F g⁻¹ (1 A g⁻¹) in the three-electrode system and 81.1% retention of the initial capacitance even after 6000 cycles. Moreover, an asymmetric device was successfully prepared using CoMoO₄@CoS and activated carbon as positive/negative electrodes. It is worth mentioning that the device delivered the high energy density of 59.2 W h kg⁻¹ at the power density of 799.8 W kg⁻¹ and the excellent cycle performance (about 91.5% capacitance retention over 6000 cycles). These results indicate that the core-shell CoMoO₄@CoS composites offers the novelty strategy for preparation of electrodes for energy conversion and storage devices.     

Polymeric gel electrolytes reinforced with glass-fibre cloth for lithium secondary batteries

Polymeric gel electrolytes (PGE), based on polyacrylonitrile blended with poly(vinylidene fluoride-co-hexafluoropropylene) (P(VdF-co-HFP)), which are reinforced with glass-fibre cloth (GFC) to increase the mechanical strength, are prepared for the practical use in lithium secondary batteries. The resulting electrolytes exhibit electrochemical stability at 4.5 V against lithium metal and a conductivity value of (2.0–2.1)×10⁻³ S cm⁻¹ at room temperature. The GFC–PGE electrolytes show excellent strength and flexibility when used in batteries even if they contain a plasticiser. A test cell with LiCoO₂ as a positive electrode and mesophase pich-based carbon fibre (MCF) as a negative electrode display a capacity of 110 mAh g⁻¹ based on the positive electrode weight at the 0.2 C rate at room temperature. Over 80% of the initial capacity is retained after 400 cycles. This indicates that GFC is suitable as a reinforcing material to increase the mechanical strength of gel-based electrolytes for lithium secondary batteries.     

Facile construction of porous C-PDA@CN-ms core-shell heterostructures with superior photocatalytic H2 evolution

Building carbon nitride (CN)-based core shell heterostructures is an effective strategy to enhance the photocatalytic performance and stability by optimize the interface area and protect the CN core, respectively. Moreover, by fabricating the porous structures in core shells can further optimize the light absorption, charge separation, and mass transfer. Herein, we have constructed porous C-PDA–CN–ms core-shell heterostructures through a facile green molten salt (ms) sculpture the polydopamine (PDA) derived carbon (C-PDA) shells with CN core. In which, the C-PDA-CN core-shells arise from in situ polymerization of dopamine (DA) on the surface of melamine to form PDA@melamine coatings followed by thermal polycondensation. The molten salts at high-temperature act as a green fluid immersing in and out of C-PDA-CN core-shells to further produce porous structures. The 1 wt% C-PDA–CN–ms with porous core-shell structures display photocatalytic H₂ evolution rate of 3830 μmol h⁻¹ g⁻¹, which is 20.8 times enhancement of 1 wt% C-PDA-CN core-shells, even 73.6 times higher than that of pristine CN. It reveals that the porous and core-shell heterostructures endow C-PDA–CN–ms enhanced light absorption, various charge transport channels for improved charge carrier separation and transfer, contributing to the superior photocatalytic H₂ evolution performance. Our work opens a new window for the green construction of porous core-shell heterostructures of CN-based photocatalysts.     

Studies on electrochemical properties of thionyl chloride reduction by Schiff base metal(II) complexes

Electrocatalytic effects associated with the reduction of thionyl chloride in a LiAlCl₄–SOCl₂ electrolyte solution containing Schiff base metal(II) (metal (M): Co, Ni, Cu and Mn) complexes are evaluated by determining the kinetic parameters for the reactions using cyclic voltammetry at a glassy carbon electrode. The charge-transfer process during the reduction of thionyl chloride is affected by the concentration of the catalyst. Catalytic effects are demonstrated from both a shift in the reduction potential for the thionyl chloride in a more positive direction and an increase in peak currents. The reduction of thionyl chloride is diffusion controlled. Catalytic effects are larger for thionyl chloride solutions containing M(II)(1,5-bis(salicylidene imino) pentane) (M(II)(SALPE)) rather than M(II)(1,3-bis(salicylidene imino) propane) (M(II)(SALPR)). Significant improvements in cell performance are found in terms of the both thermodynamics and kinetic parameters for the thionyl chloride reduction. An exchange rate constant, k⁰, of 1.89×10⁻⁸ cm s⁻¹ is found at the bare electrode, while larger values of 2.79×10⁻⁸ to 2.09×10⁻⁶ cm s⁻¹ are observed in the case of the catalyst-supported glassy carbon electrode.     

Cobalt and cobalt oxide supported on nitrogen-doped porous carbon as electrode materials for hydrogen evolution reaction

A facile method is proposed to prepare cobalt supported on nitrogen-doped porous carbon material with high graphitization degree by using chitosan as carbon source, urea as soft template and poloxamer as dispersant. The prepared cobalt-carbon material (Co@NPC) shows that uniformly distributed cobalt nanoparticles are encapsulated in nitrogen-doped porous carbon bundle with large specific surface area. When Co@NPC is applied as electrode in hydrogen evolution reaction, it exhibits superior electrocatalytic performance with low overpotential (η₁₀ = 259 mV), small Tafel slope (99 mV dec⁻¹) and high stability with 83% of its original current density remained after 6 h electrochemical test in 1 M potassium hydroxide electrolyte.     

An optimized nickel phosphate/carbon composite electrocatalyst for the oxidation of formaldehyde

The electrocatalytic performance of highly conducting Nickel phosphate (NiPh)/carbon composite catalyst is investigated for the oxidation of formaldehyde in alkaline solution. The NiPh nanoparticles are synthesized by a cost-effective one-pot method, which is based on refluxing nickel and phosphate precursors at 90 °C. Inks of the composite catalyst are produced by mixing NiPh nanoparticles with carbon conductive additives (CCA) and Nafion oil. Then, the ink is cast then dried on the glassy carbon electrode. Systematic study is performed to investigate the effect of varying the CCA loading on the electrochemical oxidation of formaldehyde. The best catalytic performance is obtained for NiPh/CCA composite catalyst containing 20 wt% of CCA (NiPh/CCA-20 wt%). The physicochemical properties of the composite catalysts are investigated and analyzed by field-emission scanning electron microscopy (FE-SEM), Energy Dispersive x-ray Spectroscopy (EDX) and X-ray diffraction (XRD). Also, the N₂ adsorption/desorption isotherms are recorded and the Brunauer–Emmett–Teller (BET) and Barrett-Joyner-Halenda (BJH) methods are used to calculate the specific surface area and pore size distribution. The electrocatalytic performance of the NiPh/CCA composite was compared to the pristine NiPh for the oxidation of formaldehyde in alkaline solution. Electrochemical impedance spectroscopy technique is used to study the electrical conductivity of the composite catalysts. Additionally, cyclic voltammetry and chronoamperometry techniques are used to calculate key parameters such as surface coverage (Γ) of Ni²⁺/Ni³⁺ species, the diffusion coefficient of the formaldehyde (D) and the catalytic rate constant (k_cat). Ã, D and k_cat values for the NiPh/CCA-20 wt% catalyst are 5.95 × 10⁻⁵ mmol cm⁻², 1.08 × 10⁻⁴ cm² s⁻¹ and 2.59 × 10⁷ cm³ mol⁻¹ s⁻¹ respectively. Both Γ and k_cat parameters are used to identify the optimum composition of the catalyst.     

Effects of TiO2 and SDC addition on the properties of YSZ electrolyte

In this study, we investigate the effects of adding titanium dioxide (TiO₂) and samarium doped cerium oxide (SDC) on the properties of yttrium-stabilized zirconia (YSZ) electrolyte. The microstructure, mechanical, and electrochemical properties of the electrolyte are investigated. The performance in CO₂ electrolysis is measured by supplying carbon dioxide to Ni-YSZ electrode and nitrogen to LSM electrode. Results show that TiO₂ and SDC addition can reduce the sintering temperature and increase grain size. The ionic conductivity is 0.123 S cm⁻¹ at 1000 °C. In addition, the thermal expansion coefficient at 1000 °C is 8.25 × 10⁻⁶ K⁻¹. The current density of the cell is 439 mA cm⁻² at 1.3 V and 1000 °C in solid oxide electrolysis cell.     

Studies on preparation and performances of carbon aerogel electrodes for the application of supercapacitor

Carbon aerogel was prepared by the polycondensation of resorcinol (R) with formaldehyde (F), and sodium carbonate was added as a catalyst (C). Physical properties of carbon aerogel were characterized by infrared spectrometer (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that carbon aerogel is an amorphous material with a pearly network structure, and it consists of one or two diffuse X-ray peaks. The results of cyclic voltammetry indicated that the specific capacitance of a carbon aerogel electrode in 6 M KOH electrolyte was approximately 110.06 F g⁻¹. Through the galvanostatic charge/discharge measurement, it was found that the electrode is stable in KOH electrolyte, the maximum capacitance of the supercapacitor with carbon aerogel as the electrode active material was 28 F g⁻¹. Besides, the supercapacitor has long cycle life. Thus, it was thought that the carbon aerogel is an excellent electrode material for a supercapcitor.     

Preparation of graphite carbon/Prussian blue analogue/palladium (GC/PBA/pd) synergistic-effect electrocatalyst with high activity for ethanol oxidation reaction

In this paper, newly graphite carbon/Prussian blue analogue/palladium (GC/PBA/Pd) synergistic-effect electrocatalyst for ethanol oxidation reaction were developed, with Co-based PBA (Co₃[Co(CN)₆]₂) as a co-catalyst. Structural analysis shows that the Co₃(Co(CN)₆)₂ nanoparticles were highly dispersed and inlaid on surface of GC nanosheets with outstanding structural stability. The GC/Co₃(Co(CN)₆)₂/Pd electrocatalyst exhibits significantly enhanced electrocatalytic activity towards ethanol oxidation with a maximum mass activity of 2644 A g^?1 Pd GC/Pd, which is more than double that of GC/Pd electrocatalyst (1249 A g^?1). Excellent electrochemical stability is also demonstrated for this GC/Co₃(Co(CN)₆)₂/Pd electrocatalyst. The enhanced electrocatalytic activity can be attributed to the synergistic effects of GC support and Co₃(Co(CN)₆)₂ promoter on the Pd electrocatalysts, in which Co₃(Co(CN)₆)₂ acts as a co-catalyst and GC acts as a conductive support.     

Symmetric redox supercapacitor with conducting polyaniline electrodes

Polyaniline doped with HCl (Pani-HCl) and LiPF₆ (Pani-LiPF₆) are prepared and used as the active electrode material of symmetric redox supercapacitors. The system using Et₄NBF₄ as an electrolyte solution has lower internal resistance and larger specific discharge capacitance, and thus, it is suitable for use in a polyaniline redox supercapacitor. The capacitance of Pani-HCl decreases during ∼400 cycles and then becomes constant at ∼40 F g⁻¹. On the other hand, the polyaniline electrode doped with lithium salt like LiPF₆ shows a specific discharge capacitance of ∼107 F g⁻¹ initially and ∼84 F g⁻¹ at 9000 cycles.     

Evaluation of nafion based double layer capacitors by electrochemical impedance spectroscopy

In this work some electrochemical characteristics of all solid double layer capacitors prepared by high surface carbon and Nafion polymer electrolyte are reported. Carbon composite electrodes with a Nafion loading of 30 wt.% were prepared and evaluated. Nafion 115 membrane, recast Nafion membrane and 1 M H₂SO₄ solution in a matrix of glass fiber have been used as electrolyte, in the double layer capacitors. The different double layer capacitors (DLCs) have been evaluated by electrochemical impedance spectroscopy. The capacitor with a recast Nafion electrolyte exhibits a proton conductivity of about 3×10⁻² S cm⁻¹ at ambient temperature, that is higher of that reported for solid electrolytes (10⁻³ to 10⁻⁴ S cm⁻¹) in the current literature on capacitors. A maximum of specific capacitance of 13 F/g of active materials (carbon+Nafion) corresponding to 52 F/g for a single electrode measured in a three-electrode arrangement has been achieved with the capacitor with recast Nafion. The capacitance of the capacitor with recast Nafion electrolyte, evaluated in low-frequency region below 10 mHz, was practically equivalent at that with sulphuric acid electrolyte. The interpretation of the characteristics of the microporous structure of carbon material of the electrodes by impedance analysis is also discussed.     

TiO2 nanotubes supported ultrafine MnCo2O4 nanoparticles as a superior-performance anode for lithium-ion capacitors

Lithium-ion capacitors (LICs) are considered as a promising energy storage device possessing large specific energy along with high specific power due to the integration of the merits of electric double-layer capacitors (ELDCs) and lithium-ion batteries (LIBs). In the present work, TiO₂ nanotubes supported ultrafine MnCo₂O₄ nanoparticles with the size of 5–10 nm is solvothermally synthesized. It is found that the introduction of TiO₂ nanotubes can weaken the aggregation of MnCo₂O₄ nanoparticles, therefore causing the enhancement in the electrode/electrolyte interfacial contact and the reduction in Li ⁺ diffusion path. Benefiting from the synergy effect of MnCo₂O₄ and TiO₂ which can alleviate the volume change of MnCo₂O₄, the MnCo₂O₄/TiO₂ composite used in LIBs displays a large reversible capacity of 743 mAh g⁻¹ at 0.2 A g⁻¹ after 100 cycles and impressive rate performance. This composite as anode is assembled with an activated carbon (AC) electrode as cathode into MnCo₂O₄/TiO₂//AC LIC working in a wide voltage range of 0.5–4 V. This LIC can deliver high specific energies of 89.8 and 44.1 Wh kg⁻¹ at specific power of 0.25 and 3.41 kW kg⁻¹, respectively, and presents outstanding cyclic stability (76.4% of initial capacity at the end of 5000 cycles).     

A cross-linked sheet structured poly(3,4-ethylenedioxythiophene) grown on Ni foam: Morphology control and application for long-life cyclic asymmetric supercapacitor

In this work, a cross-linked sheet structured conducting polymer ploy(3,4-ethylenedioxythiophene) (PEDOT) decorated on Ni foam is synthesized via one-step electrodeposition using the sodium p-toluenesulfonate (STSA) as surfactant and applied for supercapacitor electrode. The surfactants play a vital role in controlling the morphologies of PEDOT leading to the electrochemical performance difference. The optimized PEDOT electrode exhibits the highest capacitance of 711.6 mF cm⁻² at 3.0 mA cm⁻² in the three-electrode system. An asymmetric device (PEDOT/STSA//AC) is constructed by PEDOT/STSA (the positive electrode), activated carbon (AC) (the negative electrode) as well as 1 M Na₂SO₄ (the electrolyte). The device has been worked in a high-voltage range of 0–1.5 V, which displays the satisfied energy density of 14.0 Wh·kg⁻¹ at 535.5 W kg⁻¹. Furthermore, the PEDOT/STSA//AC device presents excellent rate capability and long-time cyclic stability.     

Ni–Fe nanocubes embedded with Pt nanoparticles for hydrogen and oxygen evolution reactions

Electrochemical water-splitting is widely regarded as one of the essential strategies to produce hydrogen energy, while Metal-organic frameworks (MOFs) materials are used to prepare electrochemical catalysts because of its controllable morphology and low cost. Herein, a series of trimetallic porous Pt-inlaid Ni–Fe nanocubes (NCs) are developed with bifunctions of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In the process of prepare the electrochemical catalysts, Pt nanoparticles are uniformly embedded in the Fe–Ni PBA cube structure, and ascorbic acid is employed as a reducing agent to reduce Pt²⁺ to Pt nanoparticles. In this work, the cubic structure of Fe–Ni PBA is maintained and the noble metal Pt nanoparticles are embedded. Remarkably, the formation of PBA cubes, Pt inlay and reduction are completed in one step, and Pt nanoparticles are embedded by a simple method for the first time. By employing acid etching method, a porous structure is formed on the PBA cube, which increases the exposed area of the catalyst and provides more active sites for HER and OER. Due to the porous structure, highly electrochemical active surface area and the embedded of highly dispersed Pt nanoparticles, the porous 0.6 Ni–Fe–Pt nanocubes (NCs) exhibits excellently electrocatalytic performance and durable stability to HER and OER. In this work, for HER and OER, the Tafel slopes are 81 and 65 mV dec⁻¹, the overpotential η at the current density of 10 mA cm⁻² are 463 and 333 mV, and the onset potential are 0.444 and 1.548 V, respectively. And after a 12-h i-t test and 1000 cycles of cyclic voltammetry (CV), it maintained high stability and durability. This work opens up a new preparation method for noble metal embedded MOF materials and provided a new idea for the preparation of carbon nanocomposites based on MOF.     

High-performance anode for solid acid fuel cells prepared by mixing carbon substances with anode catalysts

Optimization of Pt-based electrode structure is a key to enhance power generation performance of fuel cells and to reduce the Pt loading. This paper presents a new methodology for anode fabrication for solid acid fuel cells (SAFCs) operating at ca. 200 °C. Our membrane electrode assembly for SAFCs consisted of a CsH₂PO₄/SiP₂O₇ composite electrolyte and Pt-based electrodes. To obtain the anode, a commercial Pt/C catalyst and carbon substance, such as carbon black and carbon nanofiber, were mixed. The composite anode with Pt loading = 0.5 mg cm⁻² demonstrated superior current-voltage characteristics to a benchmark Pt/C anode with Pt loading = 1 mg cm⁻². We consider that the mixing of Pt/C catalyst and carbon substrate facilitated H₂ mass transfer and increased the number of active sites.     

One-pot sonochemical synthesis of hierarchical MnWO4 microflowers as effective electrodes in neutral electrolyte for high performance asymmetric supercapacitors

In this article, manganese tungstate (MnWO₄) microflowers as electrode materials for high performance supercapacitor applications are prepared by a one-pot sonochemical synthesis. The crystalline structure and morphology of MnWO₄ microflowers are characterized through X-ray diffraction, field emission scanning electron microscopy. The electrochemical properties of the MnWO₄ microflowers are investigated using cyclic voltammograms, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The MnWO₄ microflowers as electrode materials possess a maximum specific capacitance of 324 F g⁻¹ at 1 mA cm⁻² in the potential window from 0 to +1 V and an excellent cycling stability of 93% after 8000 cycles at a current density of 3 mA cm⁻². An asymmetric supercapacitor device is fabricated using the MnWO₄ and iron oxide (Fe₃O₄)/multi-wall carbon nanotube as the positive and negative electrode materials, it can be cycled reversibly at a potential window at 1.8 V. The fabricated ASC device can deliver a high energy density of 34 Wh kg⁻¹ at a power density of 500 W kg⁻¹ with cycling stability of 84% capacitance retained after 3000 cycles. The above results demonstrate that MnWO₄ microflowers can be used as promising high capacity electrode materials in neutral electrolyte for high performance supercapacitors.