68results about How to "Coulombic efficiency is high" patented technology

The invention relates to a lithium ion battery conducting material and a preparation method and application thereof. A graphene lithium ion battery conducting material is prepared by adopting a graphite oxide rapid heat expansion method and has high aspect ratio, which is beneficial to shortening the migration distance of lithium ions and improving the wetting quality of an electrolyte, thereby, the rate performance of an electrode is improved; the graphene lithium ion battery conducting material also has high conductivity and can ensure that an electrode active substance has higher utilization ratio and excellent cyclical stability. Compared with a common acetylene black conductive agent under the same using amount, the specific capacity of a lithium ion battery cathode constructed by the conducting material is improved by 25-40 percent, and the coulomb efficiency is improved by 10-15 percent. In addition, the method has low cost, simple process, high security and low energy consumption and is suitable for large-scale production.

The invention discloses a lithium-sulfur secondary battery system. The system comprises a positive electrode, a negative electrode and electrolyte, wherein an active substance of the positive electrode is a carbon-sulfur composite material, the negative electrode adopts a metal lithium plate, the electrolyte is high-salinity non-aqueous electrolyte, and the high-salinity non-aqueous electrolyte comprises lithium salt, sodium salt or lithium-sodium mixed salt and non-aqueous organic solvent; and the mol ratio of the lithium salt or the lithium-sodium mixed salt and the non-aqueous organic solvent is 2 to 10 mol/L. The lithium-sulfur secondary battery system has the following remarkable advantages that since the electrolyte system can effectively prevent multi-sulfur ions of the lithium-sulfur battery from being dissolved in the electrolyte in the charging and discharging processes, the multi-sulfur ions which are dissolved in the electrolyte can be prevented from producing a shuttle effect at the last stage of the charging, the over-charge phenomenon can be prevented, and the coulombic efficiency can be improved to be more than 99 percent. Therefore, the cycling performance of the battery also can be greatly improved.

The invention relates to a nitrogen-doped carbon-coated vanadium nitride electrode material as well as a preparation method and application thereof. The preparation method comprises the following steps: firstly, preparing a vanadium pentoxide nanowire precursor from vanadium pentoxide as a main raw material; by taking a pyrrole monomer as a main raw material, coating the surface of the vanadium pentoxide nanowire precursor with polypyrrole; finally performing calcining, thereby obtaining the electrode material. The preparation method is simple, high in repeatability and relatively low in equipment and chemical requirement; the prepared electrode material can be not only applied to a lithium-sulfur battery anode material, but also used as a lithium ion battery cathode material, can be compounded with graphene and is excellent in electrochemical property.

The invention relates to the field of alkaline redox flow battery energy storage, in particular to a preparation method of an ion exchange membrane for an alkaline redox flow battery, which is mainlyused for solving the problem of the high price of a Nafion diaphragm in the alkaline redox flow battery at the present stage, so that the cost of the redox flow battery is greatly reduced. An alkalineaqueous solution of ferricyanide (such as Na3[Fe(CN)6], K3[Fe(CN)6], (NH4)3[Fe(CN)6] and the like) is used as a positive electrolyte, and a strong alkaline solution (such as KOH, NaOH and the like) is used as a negative electrolyte; graphite felt and carbon felt are selected as positive electrode materials, and a zinc plate is selected as a negative electrode material; and the ionized sulfonatedpolyether ether ketone (SPEEK) diaphragm is used as an ion exchange membrane to assemble the battery. Therefore, the alkaline redox flow battery system with low cost and high performance is obtained.The flow battery system provided by the invention has the advantages of the high open-circuit voltage, the low cost, the high efficiency, the good cycling stability, safety, reliability and the like,and has a wide application prospect.

The invention relates to a battery cell hot-pressing integrally-molded solid-state battery and a preparation method thereof. The solid electrolyte of the solid-state battery comprises a polymer, and two functions of the electrolyte and a diaphragm are simultaneously achieved in the battery. The solid-state battery is fused into a whole through a hot-pressing process, so that the integrated bondingis realized in the solid-state battery, the effective interface contact between electrode materials and between the electrode materials and different functional layers, such as the solid electrolyte,etc., can be improved, a space charge layer generated by the insufficient solid-phase contact is eliminated, the interface impedance is reduced, the battery coulombic efficiency is improved, and theinterface stress generated by the volume change of the electrode in the charging and discharging process is relieved to a certain extent.

The invention relates to a preparation method of a lithium ion battery negative electrode material silicon oxide-carbon/graphite. The preparation method comprises the steps of taking tetraethyl orthosilicate as a silicon source and sucrose as a carbon source, performing in-situ combination on a gel-state silicon oxide, the sucrose and the graphite by hydrolysis-condensation reaction of the tetraethyl orthosilicate, and performing ball-milling to disperse the graphite to obtain a uniform silicon-oxygen-sucrose-graphite precursor; and allowing the sucrose to split and reducing silicon oxide during the subsequent thermal treatment process so as to prepare the uniformly-combined silicon oxide-carbon/graphite material. The in-site process of the silicon oxide and the graphite is simple in process and low in cost, and the prepared silicon oxide-carbon/graphite material is uniform in combination; with the introduction of the graphite, the electron conductivity of the composite material can beimproved, the coulombic efficiency of the composite electrode material is effectively improved, so that the electrochemical performance of the electrode material is remarkably improved; and the silicon oxide-carbon/graphite material can be used as a potential high-performance lithium ion battery negative electrode material and is expected to be widely applied to the fields of various types portable electronic equipment, an electric automobile and aerospace.

The invention discloses a high-performance cross-linked anion membrane and a preparation method thereof. The anion membrane is prepared from polymer containing benzyl halide perssad by means of biguanide or multi-guanidine cross-linking. The membrane can be applied to fuel batteries or energy storage batteries containing acid electrolyte flow. The membrane is compact in structure, low in deformation and moisture content and fine in ion selectivity, and is fine in thermal stability and anti-oxidation stability due to more dispersive distribution of positive charges. In addition, diffusion of vanadium ions in a full-vanadium-flow energy storage battery can be effectively blocked by high alkalinity of the biguanide or multi-guanidine inter-linked anion membrane, simultaneously, swelling can be inhibited by the inter-linked property, diffusion of the vanadium ions further can be inhibited, coulombic efficiency of the battery is increased to reach 99% at least, and high stability, high conductivity and low swelling are realized.

The invention belongs to the technical field of a power battery, and particularly relates to a negative electrode for the power battery. The negative electrode comprises a negative electrode current collector and a negative active substance layer, wherein the negative active substance layer is applied on a surface of the negative electrode current collector and comprises graphite and a composite material, the composite material is dispersed in gaps of the graphite and is a silicon carbon material and/or tin carbon material, the specific gravity of the graphite accounts for 10-100%, and a coating layer similar to a solid electrolyte interface film (SEI film) is arranged on a surface of the negative electrode current collector. Compared with the prior art, the negative electrode has the advantages that with the arrangement of the coating layer similar to the SEI film, the contact of an electrolyte and silicon particles/tin particles can be reduced, the negative electrode is protected, and meanwhile, the initial coulombic efficiency of a composite negative electrode can be improved. Interface modification on the negative electrode is proposed by the invention, the SEI film is simulated and constructed, the coulombic efficiency of the material and the interface compatibility of the electrolyte are improved, and the application of the silicon carbon material and the tin carbon material in the battery is promoted.

The invention discloses a tin-nickel-carbon alloy composite material for a lithium ion battery and a preparation method thereof. The method comprises the following steps of: combing tin powder and nickel powder in a mass ratio, adding a proper amount of alcohol, and performing high-energy mechanical ball milling; mixing the alloy powder obtained by the mechanical ball milling and graphite, addingalcohol, and continuously performing high-energy mechanical ball milling mixing; performing suction filtration on the tin-nickel alloy carbon composite material to remove the alcohol, then putting the composite material into an oven, performing vacuum drying, performing high-temperature thermal treatment under the protection of nitrogen, and then naturally cooling to normal temperature; and finally, taking out the prepared tin-nickel-carbon alloy composite material after cooling, adding asphalt, then adding alcohol and continuously performing high-energy mechanical ball milling, taking out the material, performing suction filtration, performing vacuum drying, performing high-temperature thermal treatment under the protection of nitrogen, and naturally cooling to normal temperature after the thermal treatment to obtain the prepared tin-nickel-carbon alloy composite material. The material has high specific discharge capacity, high coulombic efficiency and long cycle life.

The invention relates to the field of a diaphragm of an all-vanadium redox flow battery, and concretely relates to an asymmetric SPEEK/PP/FCB composite diaphragm suitable for the all-vanadium redox flow battery, and thereby, the problems of poor stability of a proton exchange membrane, poor conductivity of proton, poor vanadium resistance, and high cost in the prior art are solved. The composite diaphragm breaks through a traditional proton exchange membrane concept, the prepared composite diaphragm has good proton conductivity, vanadium resistance, mechanical properties, chemical stability, and good VRB battery performance, and provides a novel approach for commercialized preparation of the diaphragm of the all-vanadium redox flow battery.

The invention belongs to the field of new energy, and discloses graphitized carbon coated porous carbon spheres with a high specific surface area as well as a preparation method and an application ofthe graphitized carbon coated porous carbon spheres. The preparation method of the porous carbon spheres comprises the following steps of calcining phenolic resin-based nanospheres at 600-1600 DEG C in a protective atmosphere, carrying out activated pore-forming on the obtained phenolic resin-based nanospheres by using strong alkali, cleaning and drying to obtain HSCS; uniformly grinding HSCS andnickelocene to obtain a mixture, carbonizing the mixture at 600-1600 DEG C in a nitrogen atmosphere, cleaning the carbonized mixture with acid, and drying the cleaned mixture to obtain the catalyst; the phenolic resin-based nanospheres are prepared by the following steps, adding resorcinol and formaldehyde into a mixed solution of ammonia water, absolute ethyl alcohol and distilled water, stirringuntil resorcinol and formaldehyde are completely dissolved, heating in a water bath at 30-90 DEG C, carrying out hydrothermal reaction at 100-200 DEG C, centrifuging, carrying out suction filtration,washing and drying. The method is advantaged in that the porous carbon sphere has an optimized sodium storage effect, improves first coulombic efficiency of the sodium ion battery, and can be appliedto the sodium ion battery.

The invention discloses a capacitive deionization unit. The capacitive deionization unit comprises an anode current collector and a cathode current collector which are arranged at an interval, porous carbon layers are arranged on the surface of the anode current collector and the surface of the cathode current collector, and the surface of the porous carbon layer of the anode current collector is covered with an anion exchange layer. The surface of the porous carbon layer of the cathode current collector is covered with a cation exchange layer, the anion exchange layer is made of an inorganic anion selective material, and the cation exchange layer is made of an inorganic cation selective material. The invention further provides a capacitive deionization device and method. According to the invention, the same ion effect can be inhibited, the partial Faraday effect can be relieved, the coulombic efficiency of the desalination process in the capacitive deionization technology can be improved, the desalination amount is increased, the energy consumption is reduced, the desalination stability is improved, the service life of the electrode is prolonged, the device cost is reduced, and the pollution of organic matters to the porous carbon layer can be avoided.

The invention discloses a preparation method and application of a nanorod-like NiCo2O4 material, which comprises the following steps: carrying out hydrothermal reaction on cobalt salt and 2-methylimidazole to obtain CoZIF, adding the CoZIF into the cobalt salt and nickel salt water solution to carry out hydrothermal reaction, calcining the materials at 300-550 DEG C in the air atmosphere for 1-4 hours to remove the template, and washing the product with ethanol and deionized water to obtain the nanorod-like NiCo2O4 material; finally, drying the product at 60 DEG C to obtain the rod-like NiCo2O4 material. The preparation process of the nanorod-like NiCo2O4 material is simple, the equipment investment is small, the preparation period is short, the cost is low, and compared with NiCo2O4 materials prepared by other methods, the electrochemical performance of the nanorod-like NiCo2O4 material is more remarkable.

The invention provides a lithium metal alloy and a preparation method and an application thereof. The method comprises steps that alkali metal salt solid is extracted from lithium ore lixivium or purified lithium brine; the alkali metal salt solid is heated under inert gas till the alkali metal salt solid is completely melted; the melted alkali metal salt solid is melt-electrolyzed under inert gas for 1-10 hours to obtain the metal lithium alloy. The method is advantaged in that the method is simple in process, easy to operate and can realize comprehensive utilization of resources. The prepared lithium alloy has good electrochemical stability, excellent lithium ion transport capacity and mechanical properties and can be applied to metal lithium batteries to improve coulombic efficiency, specific capacity and cycle stability of the batteries.

The invention relates to a lithium ion battery, in particular to an electrolyte for a lithium secondary battery and the lithium secondary battery. The electrolyte contains an additive, the additive is selected from at least one of compounds represented by structural formulas (I)-(IX), and M is selected from hydrogen and C1-C5 alkyl; L is selected from alkali metal and silver; R1 to R16 are respectively and independently selected from hydrogen, halogen and C1-C5 alkyl groups; and n is an integer selected from 1-5. The electrolyte provided by the invention has relatively good positive and negative electrode film-forming performance and high-temperature performance, and the cycle performance of the lithium secondary battery is greatly improved.

The invention discloses a preparation method of a flexible self-supporting iron-doped porous carbon nanofiber lithium metal negative electrode framework material, and belongs to the field of lithium metal battery materials. The nanofiber is prepared by taking cheap ferric acetylacetonate, polyacrylonitrile and polymethyl methacrylate as raw materials through electrostatic spinning and high-temperature heat treatment. The lithium metal negative electrode framework prepared by the preparation method has a relatively large specific surface area, an electric field can be uniform, and local current density can be reduced, so uniform lithium deposition is caused, and formation of lithium dendrites is effectively avoided; the three-dimensional porous main body can provide open pores so as to adapt to volume change and lithium ion transmission; the nitrogen and oxygen doped carbon main body can strongly interact with lithium atoms, so that lithium nucleation becomes easier and more uniform; meanwhile, the material is simple in preparation method, relatively low in cost, green and efficient, can be produced on a large scale, can be used as an ideal high-performance lithium metal negative electrode framework material, and has a very good practical prospect.

The invention discloses a method for preparing a lithium-sulfur battery with TiO2 being as an additive. The method comprises the following steps: dispersing active substances, acetylene black and polytetrafluoroethylene in an ethanol solution according to a mass ratio of 60: 30: 10, wherein the mass of ethanol is 100 times that of the active substance, and carrying out ultrasonic treatment to obtain dispersion liquid; then, putting the dispersion liquid into a ball milling tank for ball milling to obtain slurry; coating the slurry onto an aluminum foil, and carrying out drying in a blast drying oven; and finally, putting the obtained aluminum foil into a vacuum drying oven, and carrying out drying for 12 hours at 50 DEG C in vacuum (lower than-0.8 Mpa) to obtain a positive pole piece of the lithium-sulfur battery. After TiO2 is added, the coulombic efficiency of the sulfur-lithium battery is obviously improved.