16results about How to "Improve voltage efficiency" patented technology

The invention discloses a micro-nano structure carbon fiber felt for a flow battery electrode as well as a preparation method and application thereof, the preparation method comprises the following steps: S1, adding polyacrylonitrile powder and nano boride into an organic solvent, stirring until the polyacrylonitrile powder and the nano boride are uniformly dissolved to form a spinning solution, and preparing boron-containing polyacrylonitrile nanofibers through high-voltage electrostatic spinning; s2, the boron-containing polyacrylonitrile nanofibers are subjected to pre-oxidation treatment and opening and breaking treatment, and boron-containing pre-oxidized nanofiber short filaments are obtained; s3, carrying out mixing, carding, lapping and needling treatment on the boron-containing pre-oxidized nanofiber short filaments and the chopped pre-oxidized filaments to obtain a micro-nano structure pre-oxidized felt; s4, carbonizing, graphitizing and activating the pre-oxidized felt with the micro-nano structure to obtain the carbon fiber felt with the micro-nano structure. The prepared carbon fiber felt with the micro-nano structure has a micro-nano composite structure, has relatively low resistance and relatively high electrocatalytic activity when being used for a flow battery electrode, and can effectively improve the electrochemical performance of a flow battery.

The invention belongs to the technical field of flow batteries, and discloses a universal electrode frame suitable for various flow battery stacks and a flow battery stack.The universal electrode frame is composed of a liquid inlet, a liquid outlet, a liquid inlet main flow channel, liquid inlet branch flow channels at all stages, a reaction area, a liquid outlet main flow channel and liquid outlet branch flow channels at all stages; the reaction area is used for placing a reaction electrode and a runner plate, the liquid inlet is communicated with the reaction area through the liquid inlet main runner and each stage of liquid inlet sub-runner, the reaction area is communicated with the liquid outlet through the liquid outlet main runner and each stage of liquid outlet sub-runner, and the runner plates of each stage of liquid inlet sub-runner and each stage of liquid outlet sub-runner are movably connected with the reaction area; and each stage of liquid inlet sub-runner and each stage of liquid outlet sub-runner are formed by combining changes of shapes, positions, sizes and numbers of the supporting strips. Different runner plates and porous electrodes can be matched to form an optimal flow field structure, so that electrolyte distribution is optimized, concentration polarization in a single section and between different sections is reduced, the voltage efficiency is improved, and the energy efficiency is improved.

The invention discloses a flow channel structure of a redox flow battery, and particularly relates to a three-dimensional staggered snake-shaped flow channel structure and an all-vanadium redox flow battery, the flow channel structure comprises two parts, and the two parts are positioned on the two sides of an electrode in the thickness direction and are respectively processed on the side surface, close to an electrode, of a bipolar plate and the side surface, close to a diaphragm, of the electrode; an inlet of the runner structure is formed in the bipolar plate side part, and an outlet is formed in the electrode side part; the flow channel structure of each part is snake-shaped, and the flow channel structures of the two parts are distributed in a staggered manner in the plane direction of the electrode. The technical problem that the convective mass transfer effect of reactive ions in the thickness direction of the electrode is improved by changing pressure gradient distribution in the electrode is solved. Under the same electrolyte flow supply and different current densities, the flow channel structure promotes the mass transfer process of reactive ions in the electrode, the brought overpotential loss is lower than that of a traditional flow channel, and the limiting current density is higher. In a charge-discharge experiment, the flow battery disclosed by the invention is smaller in overpotential and higher in charge-discharge capacity.

The invention relates to the technical field of ion exchange membranes of all-vanadium redox flow batteries, and discloses a cross-linked amino type polybenzimidazole composite membrane for a vanadium battery and a preparation method of the cross-linked amino type polybenzimidazole composite membrane. The preparation method comprises the following steps: S1, preparing an imidazole functional monomer 1 containing double bonds; s2, preparing a functional monomer 2 containing double bonds; step S3, preparing a cross-linked amino type polybenzimidazole solution; and step S4, preparing the cross-linked amino polybenzimidazole composite membrane. The composite membrane disclosed by the invention has a cross-linked structure, so that the acid absorption rate and the proton conductivity can be improved, the voltage efficiency of the vanadium battery can be improved, and the tensile strength and the mechanical stability of the membrane can also be improved; the nitrogen heterocyclic structure in the chain segment can inhibit vanadium ion permeation and improve coulombic efficiency.

The invention relates to the technical field of flow battery diaphragms, and discloses a polyamide-like covalent organic framework diaphragm for a vanadium battery and a preparation method of the polyamide-like covalent organic framework diaphragm. Comprising the following steps: preparing a porous base membrane; preparing covalent organic framework nanosheet dispersion liquid by a solvothermal oxidation method; preparing a two-phase solution of interfacial polymerization; and preparing the polyamide-like covalent organic framework diaphragm. The processability of the covalent organic framework can be improved by a solvothermal oxidation method. The polyamide-like covalent organic framework diaphragm has high porosity, and pore channels are rich in sulfonic acid groups, so that the proton conductivity of the diaphragm can be improved. In addition, the polyamide-like covalent organic framework diaphragm has intrinsic pore channels of a covalent organic framework and polyamide pore channels, the effective pore diameter is reduced through a hierarchical pore effect generated by staggered arrangement of the intrinsic pore channels and the polyamide pore channels, and the ion selectivity of the diaphragm and the coulombic efficiency of the battery are improved.

The invention provides a modified flow battery electrode capable of simultaneously improving activity and stability and a preparation method thereof.The method comprises the following steps that a carbon felt electrode material is added into a mixed solution of stannic chloride, manganous nitrate, melamine and urea, high-pressure treatment, ultrasonic cleaning and drying are conducted after magnetic stirring, and the modified electrode is obtained; adding the modified electrode into a mixed solution of nickel nitrate, melamine and urea, performing magnetic stirring, high-pressure treatment, ultrasonic cleaning and drying to obtain a modified electrode, immersing the modified electrode into a mixed solution of nickel nitrate, dopamine hydrochloride, polyamino acid, sodium citrate and ethanol, performing washing and drying, and then performing high-temperature treatment and pickling and drying to obtain an activated electrode; the voltage efficiency, the energy efficiency and the peak power density are greatly improved, the electrocatalytic activity of the flow battery is remarkably improved, and the stability of the electrode is also greatly improved while the electrocatalytic activity is improved.

The invention discloses a porous polybenzimidazole / proton conductor type polyamide composite ionic membrane as well as a preparation method and application thereof, and belongs to the technical field of polymer electrolyte membranes. The preparation method specifically comprises the following steps: blending proton conductor type polyamide, polybenzimidazole and an organic solvent to form a uniform system, then adding an organic pore-forming agent, pouring the volatile solvent to form a membrane, and finally soaking in acid liquor to obtain the porous polybenzimidazole / proton conductor type polyamide composite ionic membrane. The proton conductor type polyamide synthesized by the invention has certain proton conductivity, and the intrinsic proton conductivity of the ionic membrane can be improved by adding the proton conductor type polyamide into the polybenzimidazole ionic membrane instead of more dependence on adsorption of acids (including phosphoric acid, sulfuric acid and the like). Besides, due to the addition of the triethanolamine pore-forming agent, a tiny and disconnected porous structure can be formed in the ionic membrane, and higher acid absorption is obtained on the premise of ensuring the air tightness and high vanadium resistance of the ionic membrane, so that higher proton conductivity is obtained.

The present invention belongs to the technical field of all-vanadium liquid flow battery electrodes, and discloses a carbon cloth electrode for vanadium batteries and a preparation method thereof, comprising the following steps: preparing graphene oxide; reducing graphene oxide while in-situ growing a manganese cobalt oxide precursor on graphene; loading the catalyst precursor on the carbon cloth through an adhesive and calcining at high temperature to prepare a carbon cloth electrode loaded with reduced graphene oxide and manganese cobalt oxide. The present invention combines the manganese source generated when preparing graphene oxide with a cobalt source to achieve in-situ growth of manganese cobalt oxide on the surface of graphene oxide, thereby enhancing the binding force between the metal oxide and the carbon material and reducing the charge transfer resistance; a citrate compound converts potassium permanganate into manganese sulfate, then complexes manganese ions and cobalt ions, and acts as a reducing agent to reduce graphene oxide; the conductivity of graphene oxide is improved, and the ohmic polarization of the battery is reduced.

The application discloses a vanadium ion flow battery with a praseodymium sulfide composite graphite felt electrode and belongs to the technical field of flow battery electrodes. The electrode comprises a graphite felt base body and a surface-loaded praseodymium sulfide composite layer, the composite layer is composed of praseodymium sulfide nanoparticles and carbon nanomaterials, and the particle size of the nanoparticles is 5-50 nm. Preparation is carried out by mixing a praseodymium source and a sulfur source to prepare a precursor, mixing the precursor with a carbon nanomaterial dispersion liquid, performing graphite felt thermal oxidation pretreatment, hydrothermal reaction, washing and drying, and inert atmosphere heat treatment. In the application, inorganic rare earth praseodymium sulfide is used to replace organic sulfide and nitrogen-doped carbon material, Pr 3+ / Pr 4+ is used to realize efficient catalysis, the electrode is resistant to strong acid, stable in a wide temperature range, firmly combined at an interface, and long in cycle life. The electrode can be used in all-vanadium, zinc-bromine, iron-chromium and other flow batteries, is also applicable to the fields of hydrogen production by electrolysis, supercapacitors and electrocatalysis, and is mild in process and easy to scale up.

The invention relates to the technical field of ion exchange membrane materials in energy storage batteries, in particular to an amphoteric polymer material containing pyridine cations and sulfonate radicals, a preparation method of the amphoteric polymer material and application of the amphoteric polymer material in an ion exchange membrane of an all-vanadium redox flow battery, and solves the problem that an existing membrane material causes cross contamination of vanadium ions or poor ion conductivity. The polymer containing pyridine cations and sulfonate radicals is a poly (aryl-3-acetylpyridine) zwitterionic polymer; the preparation method I comprises the following steps: carrying out polymerization reaction on an aromatic monomer, zwitterionic 3-acetylpyridine and a non-ionized 3-acetylpyridine monomer under the catalysis of an organic solvent I and acid to prepare a poly (aryl-3-acetylpyridine) zwitterionic polymer containing pyridine cations and sulfonate radicals; the preparation method II comprises the following steps: polymerizing an aromatic monomer and 3-acetylpyridine, and then carrying out ionization reaction in an organic solvent III by using a sulfonating reagent and taking potassium carbonate as a catalyst to prepare the poly (aryl-3-acetylpyridine) zwitterionic polymer containing pyridine cations and sulfonate radicals.

The invention relates to the technical field of all-vanadium redox flow battery electrodes, and discloses an MXene modified graphite felt electrode for a vanadium battery and a preparation method of the MXene modified graphite felt electrode. Synthesizing a composite catalyst on the surface of MXene; the composite catalyst is loaded on the graphite felt through Nafion, and the graphite felt electrode loaded with the transition metal nitride modified MXene is obtained. The MXene modified graphite felt is used, the MXene has abundant surface groups, the hydrophilicity of the graphite felt is improved, the transmission of vanadium ions on the surface of the electrode is promoted, the charge transfer resistance is reduced due to the excellent conductivity of the MXene, and the voltage efficiency and the energy efficiency of the battery are improved; a Nafion solution is used as a binder, so that the catalyst has good ionic conductivity, the catalyst is prevented from falling off in the circulation process, electron transmission is promoted, and the voltage efficiency, the energy efficiency and the capacity retention rate of the vanadium battery are improved.

The invention belongs to the technical field of redox flow batteries, and discloses a combined electrode frame structure of a replaceable bipolar plate of an all-vanadium redox flow battery, which comprises a combined structure positive electrode frame, sealing rubber, a bipolar plate and a combined structure negative electrode frame, the use of sealant is reduced by adopting a mechanical sealing mode, the cost is greatly saved, the sealing effect between the electrode frame and the bipolar plate is improved by adopting a plurality of layers of sealing grooves, the bipolar plate can be directly replaced without influencing other parts after being damaged in operation, the waste of materials is reduced, the bipolar plate is arranged in the electrode frame, and the service life of the bipolar plate is prolonged. The use amount of the bipolar plate is reduced by 30%, the overall thickness of the electric pile is reduced, the voltage efficiency of the electric pile is improved, and the energy efficiency of the electric pile is improved; according to the design, a bipolar plate tab for measuring the voltage of a single battery is reserved, so that the detection is convenient.

This invention discloses a carbon-plastic bipolar plate for a zinc-bromine flow battery, its preparation method, and its application, belonging to the field of electrochemical energy storage technology. The method includes: dispersing nitrogen-doped hollow carbon nanotubes and spraying them onto the positive electrode side of a carbon-plastic bipolar plate; after drying, a nitrogen-doped hollow carbon nanotube-modified positive electrode carbon-plastic bipolar plate is obtained; dispersing boron-nitrogen co-doped carbon and spraying it onto the negative electrode side of a pretreated carbon-plastic bipolar plate, after drying again, a boron-nitrogen co-doped carbon-plastic negative electrode carbon-plastic bipolar plate is obtained. On the positive electrode side, the nitrogen-doped hollow carbon nanotubes catalyze the bromine reaction through nitrogen doping, reducing the overpotential; the hollow structure adsorbs bromine species and uses charge action to inhibit bromine permeation, reducing self-discharge. On the negative electrode side, the boron-nitrogen co-doped carbon uses B-N zinc-loving sites to guide uniform and dense zinc deposition, inhibiting dendrite formation; and inhibits hydrogen evolution through charge regulation. Both methods synergistically improve the bromine barrier performance, reaction kinetics, and dendrite suppression ability of the carbon-plastic bipolar plate.

The invention provides an ion conducting membrane with an ultra-high porosity structure, a preparation method of the ion conducting membrane and a battery, the ion conducting membrane has a porous structure, the ion conducting membrane comprises a hydrophobic polymer material and a hydrophilic polymer material, the hydrophilic polymer material has water swelling property, the porosity of the ion-conducting membrane is 80% by volume or more, and the average pore size of the porous structure is 4-30 nm.

The present invention relates to the technical field of all-vanadium liquid flow battery diaphragms, and in particular to an integrated membrane electrode for vanadium batteries and a preparation method thereof. It includes preparing a membrane-making liquid A and a membrane-making liquid B using different components. Then, a porous reinforced membrane with membrane-making liquid A on both sides and an electrode impregnated with membrane-making liquid B are prepared. Finally, an electrode-membrane-electrode integrated assembly is prepared. The present invention uses monomers with alkaline nitrogen-containing groups and cross-linking agents for cross-linking polymerization and interacts with sulfonic acid polymers with high charge density, so that the membrane has both high vanadium resistance and high ionic conductivity. At the same time, cross-linking polymerization is combined with a porous reinforced membrane to make the membrane have high stability. Finally, by preparing an electrode-membrane-electrode integrated assembly, the ion transport of ions at the interface between the membrane and the electrode is enhanced, and the voltage efficiency of the battery is improved.

The invention belongs to the technical field of electrochemical energy storage, and relates to a positive and negative differential integrated electrode for a static filmless zinc-bromine battery and a battery stack. The electrode comprises a flexible graphite composite bipolar plate, one side of the flexible graphite composite bipolar plate is compounded with a non-conductive negative electrode thin pre-oxidized felt subjected to oleophobic modification, the other side of the flexible graphite composite bipolar plate is compounded with a positive electrode thick activated graphite felt which has a gradient pore structure and is loaded with a bromine oxidation reduction catalyst, the contact side of the bipolar plate and the negative electrode felt is activated, and the three layers are compounded into an integrated structure. The stack is horizontally placed, positive and negative electrode felts of adjacent electrodes are directly attached and compressed, no diaphragm exists, and the compression ratio is controlled by a limiting column. Three-dimensional uniform deposition of zinc is guided through the negative electrode non-conductive felt, the bromine oil phase is locked through cooperation of positive electrode gradient pores and gravity settling, the contact resistance is reduced through the integrated structure, non-film static operation is achieved, the cycle life exceeds 500 times, the self-discharge rate is lower than 0.45%, the energy efficiency is higher than 80%, the structure is simplified, and the lithium ion battery is suitable for large-scale production.