45 results about "Vanadium doping" patented technology

The invention discloses a vanadium-doped modified ferric sodium pyrophosphate material based on spray drying as well as a preparation method and application of the vanadium-doped modified ferric sodium pyrophosphate material. The material has a spherical porous morphology, and the particle size is 1-10 microns; the chemical formula is Na (4-x) Fe (3-x) Vx (PO4) 2P2O7, wherein x is more than 0 and less than or equal to 0.1. The material is prepared by adopting a spray drying method, and atomic-scale mixing of vanadium and iron is ensured through a uniform and stable complexing ion solution; and the formation of porous spherical morphology is promoted through the volatilization of the acidic base solution in the rapid drying process. A spray drying method and a trace vanadium doping technology are combined, so that more active sodium sites in the ferric sodium phosphate pyrophosphate positive electrode material can be activated, the reversible de-intercalation sodium capacity can be improved, sodium ion diffusion can be promoted, the polarization voltage can be reduced, and the cycling stability of the material can be improved.

The invention discloses a vanadium iron-site doped iron phosphate material and a preparation method, and relates to the technical field of lithium ion battery positive electrode material preparation, pure water is used as a base solution, and a vanadium salt solution with the pH value of 2.0-3.0, a ferrite solution with the pH value of 1.0-2.5 and a phosphorus-oxygen mixed solution with the pH value of 5.0-7.0 are simultaneously added into a reaction kettle in a three-strand parallel flow mode for a co-precipitation reaction. By controlling the acid environment of a key solution system, reduction of metavanadate radicals or generation of ferric vanadate precipitates is effectively inhibited, and vanadium elements are successfully and uniformly doped to iron sites of iron phosphate crystal lattices; the mass ratio of iron to phosphorus in the obtained iron phosphate material is stabilized at 95-98%, the doping amount of vanadium is 100-10000 ppm, and the vanadium is uniformly distributed. Lithium iron phosphate prepared by taking the material as a precursor has higher discharge capacity and compaction density, and the electrochemical performance of a lithium ion battery is remarkably improved.

The application discloses a preparation method of vanadium-doped and high-hydrated mangan-chromian spinel monocrystal under high temperature and high pressure. The cylindrical mangan-chromian spinel sample is prepared by taking solid rose triangular rhombic manganese carbonate crystal, solid chromium (III) acetate hydroxide crystalline powder, solid vanadium (IV) acetylacetonate oxide powder, solid oxalic acid powder, solid bixbyite powder, solid chromium hydroxide powder and liquid dilute nitric acid as starting raw materials; two pieces of water source sheets are made from the bixbyite powder and the chromium hydroxide powder with a weight ratio of 4:1; the two pieces of water source sheets are placed at two ends of the cylindrical mangan-chromian spinel sample and then are placed into a double-capsule structure experimental sample bin with an inner layer sleeve being a graphite tube and an outer layer sleeve being a gold-palladium alloy tube; the high temperature and high pressure reaction is carried out to obtain the mangan-chromian spinel monocrystal; and the preparation technology blank of the vanadium-doped and high-hydrated mangan-chromian spinel large-particle monocrystal under the current high temperature and high pressure conditions is solved.

The invention discloses a high-magnification vanadium-doped negative electrode material preparation method, which comprises: dissolving niobium oxalate in a strong acid solution, adding ammonium ferric citrate to the acidic niobium oxalate solution to obtain a reaction solution, transferring to a reaction kettle, carrying out a constant temperature reaction, placing in a box-type furnace, and calcining to obtain the high-magnification vanadium-doped negative electrode material. And calcining and doping vanadium ions to obtain the vanadium-doped negative electrode material. The iron-niobium oxide is selected as the negative electrode material and calcined to dope the vanadium element in the iron-niobium oxide, and the negative electrode material can still maintain relatively good cycling stability, rate capability and safety in a high-voltage environment by utilizing the lithium intercalation stability of the iron-niobium oxide, a lithium storage mechanism and a relatively high working voltage platform of the iron-niobium oxide; and the migration potential barrier of lithium ions in the iron-niobium oxide is reduced by doping vanadium ions, so that the rate capability of the iron-niobium oxide and the cycling stability under the high rate condition are improved.

The invention discloses a preparation method and application of a vanadium-doped titanium dioxide composite material, and relates to the technical field of titanium dioxide composites.The preparation method comprises the following steps that 1, ammonium vanadate and titanium dioxide are mixed in proportion, the doping amount of the vanadium element is controlled to range from 0.1 wt% to 12.5 wt% according to the total mass of the mixture, then high-temperature heating is conducted, and a mixture is obtained; vanadium-doped titanium dioxide powder is obtained; and (2) mixing the vanadium-doped titanium dioxide powder with a carrier in proportion, controlling the content of the vanadium-doped titanium dioxide powder to be 10-30 wt% based on the total mass of the composite material, and carrying out physical grinding to obtain the powdery vanadium-doped titanium dioxide composite material. The catalytic material disclosed by the invention is applied to degradation of sulfur hexafluoride and has excellent degradation capability.

This invention discloses a vanadium-doped modified sodium iron pyrophosphate material based on spray drying, its preparation method, and its applications. The material exhibits a spherical porous morphology with a particle size between 1 and 10 micrometers; its chemical formula is: Na. 4‑x Fe 3‑x V x (PO4)2P2O7, where 0 < x ≤ 0.1. It is prepared by spray drying, ensuring atomic-level mixing of vanadium and iron through a uniform and stable complexed ion solution; and promoting the formation of a porous spherical morphology through the volatilization of the acidic substrate during rapid drying. The combination of spray drying and trace vanadium doping technology is beneficial for activating more active sodium sites in the sodium iron pyrophosphate cathode material, improving the reversible sodium insertion / extraction capacity, while promoting sodium ion diffusion, reducing polarization voltage, and improving the cycle stability of the material.

The invention provides a vanadium-doped Co9S8 nanosheet array as well as a preparation method and application thereof. The invention provides a vanadium-doped Co9S8 nanosheet array preparation method, which comprises: dissolving a cobalt salt and 2-methylimidazole in deionized water, adding foamed nickel, and carrying out a reaction at a room temperature to obtain a Co-ZIF nanosheet array precursor; then adding the VCo-ZIF nanosheets into a sodium metavanadate solution, and carrying out hydrothermal reaction to obtain a VCo-ZIF nanosheet array; and finally, adding the VCo-ZIF into a sulfur source solution, and vulcanizing to obtain the vanadium-doped Co9S8 nanosheet array. The formed porous nanosheet structure can provide a larger active specific surface area, the synergistic effect between Co and V ions can improve the charge storage capacity of the material, and sulfur vacancies on the surface of the electrode material can increase the conductivity and the number of active sites. Practice shows that when the material is used as a supercapacitor electrode material, the specific capacity and the rate capability are remarkably improved.

The invention belongs to the technical field of multiferroic materials, and relates to a design method of a multiferroic body based on a vanadium-doped two-dimensional ferroelectric and the multiferroic body. Performing cell expansion on the single-layer NbOI2 primitive cell in different directions to obtain supercells with different sizes; the method comprises the following steps: doping supercells with different sizes by taking vanadium as a doping element to obtain a doping configuration of each supercell under different doping concentrations; taking the doping configuration with the lowest total energy of the ferromagnetic state and the antiferromagnetic state under each doping concentration as the ground state configuration of the doping concentration; calculating band gaps Eg of ground state configurations with different doping concentrations and spontaneous ferroelectric polarization intensity along a b axis, drawing a double-Y-axis curve graph by taking the doping concentrations as abscissas and the spontaneous ferroelectric polarization intensity and the band gaps Eg as ordinates, and dividing a multiferroic phase region and a magnetic semimetal phase region to obtain a doping concentration-physical property evolution phase diagram; and obtaining a corresponding doping concentration value range when the ground state configuration has a multiferroic phase with ferroelectricity and antiferromagnetism so as to design a multiferroic body.

The present invention reports the development of electrochromic supercapacitor application that comprises the vanadium doped cobalt chloride carbonate hydroxide. And, more particularly, developing a process to synthesize for use as electrochromic supercapacitor application. Methods of preparing the material and use for electrochromic supercapacitor application of the invention are also described. The catalyst shows a high capacitance value of the electrochromic supercapacitor having a capacitance value of 1219 F / g in alkaline medium with an optical modulation (∆T) value of 69% coloration efficiency value of 65 cm2c-1 at a wavelength of 600 nm. This invention provides a new vision for developing materials with dual characters, i.e., storing energy and changing its color for promising electrochromic supercapacitor applications.

The invention discloses a preparation method and application of a vanadium-doped molybdenum nitride-nickel nitride-nickel three-phase heterojunction composite material, and relates to a preparation method of a catalyst for hydrogen production by alkaline electrolysis of water. The invention aims to solve the problems of high cost and low catalytic activity of the existing catalyst for hydrogen production by alkaline electrolysis of water. According to the preparation method, a polyacid-nickel hydroxide nanosheet complex is obtained based on a molecular assembly principle by utilizing hydrogen bonds and electrostatic interaction between nickel hydroxide nanosheets and polyacids, and the vanadium-doped molybdenum nitride-nickel nitride-nickel three-phase heterojunction composite material is prepared after nitridation treatment. The composite material has the advantages that components are tightly combined and uniformly distributed, the components are easy to regulate and control, the structure is stable, active sites are rich and the like, when the composite material is used as a catalyst for an electro-catalytic hydrogen evolution reaction, the required overpotential is only 34 mV when the current density is 10 mAcm <-2 > under the alkaline condition, and a foundation is laid for designing and preparing an electrochemical hydrogen evolution catalyst used under the alkaline condition in the future.

A method of generating hydrogen including applying a potential of −0.1 volts (V) to −1.0 V to an electrochemical cell, and the electrochemical cell is at least partially submerged in an aqueous solution. Further, on the application of the potential, the aqueous solution is reduced, thereby forming hydrogen. The electrochemical cell includes an electrocatalyst and a counter electrode. The electrocatalyst includes a substrate and vanadium-doped manganese spinel oxide microspheres (MnVxCo2-xO4) particles. The value of x is ≤0.4, the MnVxCo2-xO4 particles have a spherical shape, the MnVxCo2-xO4 particles have an average diameter of less than 100 nanometers (nm), and the MnVxCo2-xO4 particles are dispersed on the substrate to form the electrocatalyst.

The application discloses a kind of vanadium doped nickel phosphide material of spherical micrometer flower structure and its preparation method and application, belong to electrolytic water hydrogen production material technical field.Method includes the following steps: (1) foam nickel is ultrasonically cleaned, dry;(2) deionized water, isopropanol, urea, NH4F, VCl3, Ni (NO3) 2·6H2O and the foam nickel treated in step (1) are placed in reaction vessel, heated reaction using hydrothermal method, obtain nickel vanadium oxide grown on foam nickel matrix;(3) nickel vanadium oxide obtained in step (2) and sodium hypophosphite are respectively loaded into porcelain boat, calcine in inert gas atmosphere, obtain vanadium doped nickel phosphide material of spherical micrometer flower structure.Afficient: the vanadium doped nickel phosphide material prepared in the application, according to electrochemical test results, vanadium doped nickel phosphide electrode of spherical micrometer flower structure shows excellent electrocatalytic performance, when current density is 10mA·cm ‑2 , overpotential is only 85mV;It has broad application prospect.

The application belongs to the technical field of multiferroic materials, and relates to a design method of a multiferroic material based on a vanadium-doped two-dimensional ferroelectric body and the multiferroic material. Single-layer NbOI2 primitive cells are expanded in different directions to obtain supercells of different sizes. Vanadium is used as a doping element to dope the supercells of different sizes, and the doping configurations of each supercell under different doping concentrations are obtained. The doping configuration with the lowest total energy of the ferromagnetic state and the antiferromagnetic state under each doping concentration is used as the ground state configuration of the doping concentration. The band gap Eg and the spontaneous ferroelectric polarization intensity along the b-axis of the ground state configuration under different doping concentrations are calculated. A double-Y-axis curve graph is drawn with the doping concentration as the horizontal coordinate and the spontaneous ferroelectric polarization intensity and the band gap Eg as the vertical coordinate, and the multiferroic phase region and the magnetic semimetal phase region are divided. The doping concentration-physical property evolution phase diagram is obtained, so that the corresponding doping concentration value range of the ground state configuration with the multiferroic phase of ferroelectricity and antiferromagnetism is obtained to design the multiferroic material.

This invention discloses a method for the electrocatalytic reduction of carbon dioxide to solid carbon using gallium-based liquid metal. The method employs a composite working electrode, using a platinum sheet electrode as the counter electrode and an Ag / AgCl electrode as the reference electrode. Solid carbon is prepared through an electrocatalytic reduction reaction in an organic electrolyte continuously purged with carbon dioxide until saturation. The composite working electrode is prepared as follows: using a copper sheet as a substrate, gallium-based liquid metal is treated with dilute hydrochloric acid to remove its surface oxide film, and then capillary action is used to uniformly coat the copper sheet surface. The gallium-based liquid metal is prepared by: mixing gallium, indium, and tin in a specific ratio and heating to obtain a gallium-indium-tin alloy; subsequently, under an inert atmosphere, vanadium powder is ground and mixed with the alloy to achieve uniform vanadium doping, forming more active sites, thereby significantly promoting the generation of solid carbon and effectively improving its Faraday efficiency, thus improving catalytic performance.

The invention discloses an in-situ constructed VCN / ED-BiVO4 heterojunction as well as a preparation method and application of the in-situ constructed VCN / ED-BiVO4 heterojunction. The method mainly comprises the following steps: treating bismuth vanadate by utilizing a simple and convenient one-step electrochemical method, so that vanadium-doped carbon nitride (VCN) modification and oxygen vacancy generation by electrochemical reduction of the bismuth vanadate are synchronously realized, and the VCN / ED-BiVO4 composite photoelectrode is obtained. The prepared photo-anode can be used in the field of photoelectrocatalytic water decomposition. Under the synergistic effect of a VCN heterostructure and oxygen vacancy engineering, the separation and transfer efficiency of photogenerated charges can be effectively improved, meanwhile, the interface exchange resistance can be reduced, interface oxygen evolution reaction kinetics can be promoted, and finally the performance of photoelectrocatalytic water decomposition is effectively improved.

This invention provides a vanadium-doped lithium iron phosphate cathode material, its preparation method, and its application, belonging to the field of lithium-ion battery material technology. The vanadium-doped lithium iron phosphate cathode material prepared by the method of this invention has excellent electrochemical performance. When applied to the subsequent preparation of lithium-ion batteries, the resulting lithium-ion batteries have the characteristics of high discharge specific capacity and high initial charge-discharge efficiency. Furthermore, the preparation method of the vanadium-doped lithium iron phosphate cathode material provided by this invention has mild conditions and simple operation, which is beneficial to actual production.

A nanocomposite electrode and supercapacitor thereof are disclosed. The nanocomposite electrode includes a substrate, at least one binding compound, at least one carbonaceous compound, and vanadium doped spinel ferrite nanoparticles (V-SFNPs). The V-SFNPs have a formula of CoxNi1-xVyFe2-yOz, wherein x=0.1-0.9, y=0.01-0.10, and z=3-5. The substrate is at least partially coated on a first side with a mixture comprising the V-SFNPs, the at least one binding compound, and the at least one carbonaceous compound. Two of the nanocomposite electrodes are combined to form the supercapacitor.

The application provides a vanadium-doped nickel-cobalt-manganese ternary positive electrode material and a preparation method and application thereof. The preparation method comprises the following steps: providing a vanadium citrate aqueous solution, evaporating and crystallizing the vanadium citrate aqueous solution and performing primary roasting to obtain anhydrous vanadium citrate; mixing the anhydrous vanadium citrate with a lithium nickel cobalt manganese oxide to obtain a mixture, and performing secondary roasting on the mixture to obtain the vanadium-doped nickel-cobalt-manganese ternary positive electrode material. The molecular formula of the obtained vanadium-doped nickel-cobalt-manganese ternary positive electrode material is LiNi x Co y Mn z V a O2, 0.8≤x≤0.96, 0.02≤y≤0.2, 0.02≤z≤0.2, 0.0013≤a≤0.0043. The preparation method is simple, and the vanadium-doped nickel-cobalt-manganese ternary positive electrode material prepared by the method is beneficial to significantly improving the performance of the positive electrode material, reducing the production cost and saving the energy consumption.

The present invention discloses a vanadium-doped nitrogen-fluorine-doped vertical graphene material and a perovskite solar cell, relating to the technical field of perovskite solar cells. The technical solution is as follows: adding graphite oxide to deionized water for ultrasonic treatment, adding ammonia and ethylene glycol for hydrothermal reaction, and freeze-drying to obtain a three-dimensional graphite foam; immersing the three-dimensional graphite foam in a vanadium ion solution to adsorb vanadium; drying and heat-treating with argon to obtain a V-3D-GO material; heating and introducing methane in a CVD system to obtain VG@V-3D-GF for vertical graphene growth; and performing a nitrogen-fluorine plasma reaction to obtain a vanadium-doped nitrogen-fluorine-doped vertical graphene material. The present invention uses three-dimensional graphene foam instead of sponge nickel to achieve ternary co-doping through vanadium-doped nitrogen-fluorine doping, thereby improving conductivity and stability. The CVD process is used to simplify the preparation process and improve production efficiency and consistency. The material improves photoelectric conversion efficiency and stability in perovskite solar cells.

An apparatus and a method for producing a photovoltaic solar cell. The apparatus includes a planar silicon base. At least one thin film layer of vanadium (V) doped zinc oxide (ZnO), at least one thin film layer of perovskite precursor solution, or at least one thin film layer of perovskite quantum dots is applied on said silicon base to enhance efficiency and prolong life of the solar cell. A layer of polydimethylsiloxane may be applied to prolong life of the perovskite quantum dots.

The invention relates to a Fe-Mo-V ternary sulfide electrocatalytic ammonia synthesis catalyst, in particular to the technical field of electrochemical green hydrogen production of green ammonia. The catalyst is composed of iron, molybdenum, vanadium and sulfur elements, has a chemical general formula of FeaMo [beta] V [gamma] S, and has a porous nanosheet structure with a specific surface area. The preparation method comprises the following steps: dissolving an iron source, a molybdenum source and a vanadium source in water in proportion, adding a sulfur source, carrying out a hydrothermal reaction, carrying out centrifugal washing, and annealing in a hydrogen-containing inert atmosphere. According to the catalyst, an iron-molybdenum electronic structure is reconstructed through vanadium doping, Fe-V double active centers are formed to synergistically promote nitrogen adsorption and N = N bond breakage, and meanwhile, a proton transfer path is perfected through molybdenum and sulfur sites. The invention is applied to proton exchange membrane electrolytic cell cathodes. The porous nanosheet structure accelerates nitrogen mass transfer, V-S bonds strengthen lattice stability, and the problems of weak nitrogen activation, serious hydrogen evolution competition and sulfur loss of a traditional catalyst are solved. The process is suitable for large-scale production, the energy consumption of single electrolysis is reduced to 28.6 kWh / kgNH3, and a high-efficiency and low-cost catalysis scheme is provided for green ammonia industrialization.

The invention discloses a vanadium-containing positive electrode material and a preparation method thereof, and a positive electrode and a sodium ion battery adopting the vanadium-containing positive electrode material and a preparation method thereof. The vanadium-containing positive electrode material disclosed by the invention has a composition as shown in a formula I: NaxMaVbNy (formula I), wherein M is selected from at least one of Mn, Ni, Co, Fe, Cu, Ti and Zn; v is vanadium; n is nitrogen; wherein 0.5 < = x < = 1.5, 0.1 < = a < = 0.9, 0.6 < = b < = 1.5, and 0.3 < = y < = 0.5. According to the invention, by optimizing the structural design of the nitride and the vanadium doping element, the phase change is inhibited, the cycle attenuation is reduced, and the long-term stability and the cyclicity of the battery are improved.

The invention discloses a vanadium-doped graphene nanosheet and a preparation method thereof, and belongs to the technical field of graphene. The preparation method of the vanadium-doped graphene nanosheet comprises the following steps: taking a vanadate-containing solution as an electrolyte, and electrochemically stripping a graphite-containing raw material to obtain the vanadium-doped graphene nanosheet, the vanadate is selected from at least one of potassium vanadate, sodium vanadate and ammonium vanadate; the concentration of the vanadate solution is 0.01 to 10 mol / L; the graphite-containing raw material is selected from at least one of microcrystalline graphite, graphite rods, natural crystalline flake graphite, graphite paper and graphite foil; the electrochemical stripping voltage is 2-20V, the electrochemical stripping time is 5 minutes to 48 hours, and the electrochemical stripping temperature is 5-50 DEG C; the size of the vanadium-doped graphene nanosheet is 0.5-200 [mu] m, and the number of layers of the vanadium-doped graphene nanosheet is 1-7. The preparation method disclosed by the invention is simple to operate, safe, controllable, low in cost, high in efficiency, green, environment-friendly and small in corrosion to an electrochemical stripping device.

The application relates to the field of lithium ion batteries, and discloses a titanium dioxide composite negative electrode material, a preparation method of the titanium dioxide composite negative electrode material, a negative electrode sheet and a lithium battery. The negative electrode material comprises nanometer titanium dioxide, a vanadium ion doped titanium dioxide ultrathin layer and a carbon nanotube layer; the nanometer titanium dioxide is a core, is coated by the vanadium ion doped titanium dioxide ultrathin layer, and the carbon nanotube layer coats the vanadium ion doped titanium dioxide ultrathin layer. The application thins the thickness of a contact potential barrier by constructing a vanadium doped ultrathin tunneling layer between nanometer titanium dioxide and a carbon nanotube, the vanadium doped ultrathin tunneling layer matches an interface crystal lattice of the nanometer titanium dioxide layer, and the unique tunneling effect of the vanadium doped ultrathin tunneling layer can accelerate the transfer rate of electrons from the nanometer titanium dioxide to the carbon nanotube, thereby improving the various electrochemical performances of the composite material.

The application discloses a preparation method of a vanadium-doped titanium dioxide composite material and application thereof, relates to the technical field of titanium dioxide composite materials, and comprises the following steps: (1) mixing ammonium vanadate and titanium dioxide according to a proportion, controlling the doping amount of vanadium elements to be 0.1 wt%-12.5 wt% according to the total mass of the mixture, and then high-temperature heating to obtain vanadium-doped titanium dioxide powder; (2) mixing the vanadium-doped titanium dioxide powder and a carrier according to a proportion, controlling the content of the vanadium-doped titanium dioxide powder to be 10 wt%-30 wt% according to the total mass of the composite material, and performing physical grinding to obtain the powder-shaped vanadium-doped titanium dioxide composite material. The catalytic material has superior degradation capacity when applied to the degradation of sulfur hexafluoride.

The invention belongs to the technical field of electro-catalytic materials, and particularly relates to a preparation method and application of a vanadium-doped cobalt phosphide heterogeneous composite material. The preparation method comprises the following steps: firstly, growing a ZIF-67 precursor on carbon cloth by an impregnation method to obtain ZIF-67 / CC; then, the ZIF-67 / CC is soaked in a sodium metavanadate solution for etching, and a Co3V2O8 / CC intermediate is formed; the vanadium-doped cobalt phosphide heterogeneous composite material has excellent electro-catalysis oxygen evolution performance and good full water decomposition performance under the alkaline condition, shows excellent conductivity and good stability, can be used as an excellent catalyst for electro-catalysis oxygen evolution reaction, and has good application prospects. The preparation method has certain practical application potential, and is simple, short in process and convenient for commercial popularization.

The invention discloses a three-dimensional porous lithium iron manganese phosphate positive electrode material and a preparation method thereof, and belongs to the technical field of lithium batteries. A three-dimensional porous LMFP precursor is prepared through spray granulation and two-stage sintering, bulk phase vanadium doping and surface layer magnesium-niobium gradient co-doping are achieved through a CVD technology, and then a target material is obtained through conducting polymer-fast ion conductor dual coating. The material has high tap density, excellent rate capability and strong manganese dissolution resistance, the process is easy to amplify, and the material is suitable for high-energy-density lithium ion batteries.

The present application relates to the field of electrocatalytic hydrogen evolution, and discloses a preparation method and application of a foam nickel loaded polyacid derivative vanadium doped nickel molybdenum sulfide. The present application aims to solve the problems of raw material shortage, high hydrogen evolution overpotential and high cost in the prior art for synthesizing high-performance electrocatalysts. The present application designs and develops a foam nickel loaded vanadium doped nickel molybdenum sulfide material V-MoS2 / Ni3S2@NF-Mo. The method comprises the following steps: taking Keplerate type polyacid Mo 72 V 30 , thiourea as a sulfur source, and foam nickel as a conductive substrate, and adopting a one-step hydrothermal synthesis method to prepare foam nickel loaded polyacid derivative flower-like vanadium doped nickel molybdenum sulfide, which can be applied to electrocatalytic hydrogen evolution reaction in an alkaline electrolyte and has low hydrogen evolution overpotential and high catalytic activity.

The invention provides vanadium-doped carbon-coated sodium ferric sulfate and a preparation method and application thereof.The preparation method of the vanadium-doped carbon-coated sodium ferric sulfate comprises the following steps that an iron source, a vanadium source, a sodium source, pure water and an organic carbon source are mixed and react to obtain a Na2Fe2-1.5 xVxO3 precursor, the Na2Fe2-1.5 xVxO3 precursor is placed in an inert atmosphere to be roasted and then mixed with a sulfur source and an inorganic carbon source, and the vanadium-doped carbon-coated sodium ferric sulfate is obtained. Carrying out sanding and spray drying to obtain a vanadium-doped sodium ferric sulfate precursor; and roasting the vanadium-doped sodium ferric sulfate precursor in an inert atmosphere to obtain vanadium-doped carbon-coated sodium ferric sulfate. According to the vanadium-doped carbon-coated sodium ferric sulfate prepared by the preparation method disclosed by the invention, the intrinsic electronic conductivity of the material is improved under the condition of extremely low doping amount, ferrous iron oxidation can be inhibited to a certain extent, and the vanadium-doped carbon-coated sodium ferric sulfate is good in crystallinity, complete in carbon coating and relatively high in compaction density, and has a good application prospect and large-scale popularization potential in the field of sodium ion batteries.

The present invention reports the development of electrochromic supercapacitor application that comprises the vanadium doped cobalt chloride carbonate hydroxide. And, more particularly, developing a process to synthesize for use as electrochromic supercapacitor application. Methods of preparing the material and use for electrochromic supercapacitor application of the invention are also described. The catalyst shows a high capacitance value of the electrochromic supercapacitor having a capacitance value of 1219 F / g in alkaline medium with an optical modulation (ΔT) value of 69% coloration efficiency value of 65 cm2c−1 at a wavelength of 600 nm. This invention provides a new vision for developing materials with dual characters, i.e., storing energy and changing its color for promising electrochromic supercapacitor applications.