14 results about "Cyclic stability" patented technology

The invention discloses a composite electrolyte membrane based on a functional polymer. The composite electrolyte membrane is mainly composed of a polymer porous diaphragm, a lithium perfluoro-sulfonamide single-lithium ion type polymer electrolyte coating which coats one side of the polymer porous diaphragm and a gel polymer coating which coats the other side of the polymer porous diaphragm, is stable to a lithium negative electrode and has a free radical capture function. A preparation method for the composite electrolyte membrane comprises the following steps: reacting a perfluoro-sulfuryl fluoride resin with lithium methide containing double electron-withdrawing groups so as to obtain a lithium perfluoro-sulfonamide polymer; carrying out washing and dissolving, then coating one side of the polymer porous diaphragm with the lithium perfluoro-sulfonamide polymer and adding a non-solvent for secondary film formation; and coating the other side of the polymer porous diaphragm with a gel polymer system which is stable to the lithium negative electrode, contains an additive and comprises a mixed liquor of a polymer, a solvent, a free radical annihilation effect additive and a nanometer filling material, and then carrying out drying so as to prepare the composite electrolyte membrane. The composite electrolyte membrane can improve cycling stability of a lithium-sulfur secondary cell.

The invention relates to a lithium silicate-coated Ni-Co lithium aluminate positive electrode material and a preparation method thereof. The mass percent of lithium silicate in the material accounts for 1-10wt%, a coating layer with a thickness being 2-20 nanometers is formed from the silicon silicate and is coated on Ni-Co lithium aluminate, and the positive electrode material is a spherical particle with a grain size being 5-15 micrometers. The method comprises the following steps of (1) adding a silicon source into an organic solvent, performing uniform stirring, adding water, adding Co-Alnickel hydroxide, performing heating and stirring reaction, and performing drying to obtain silicon dioxide-coated Co-Al nickel hydroxide precursor powder; and (2) grinding and uniformly mixing the silicon dioxide-coated Co-Al nickel hydroxide precursor powder and a lithium salt, placing the mixture in a tubular furnace, and performing two-segment calcination under an oxidization atmosphere, thereby obtaining the lithium silicate-coated Ni-Co lithium aluminate positive electrode material. The positive electrode has relatively good cycle stability and large-rate discharging performance; and bythe method, the problem of lithium resided on a surface during conventional coating can be effectively reduced, and the method is low in cost and simple in process and is suitable for industrial production.

The invention relates to the technical field of photocatalysis, and specifically relates to a graphene-based gamma-FeO2O3 composite material photocatalyst, and a preparation method and use thereof. According to the graphene-based gamma-FeO2O3 composite material photocatalyst, gamma-Fe2O3 particles are attached to the surface of graphene, size distribution of the graphene is 1-50 mu m and the size distribution of the gamma-Fe2O3 particles is 20-500nm. The preparation method mainly comprises the following steps: preparation of graphite oxide; preparation of a graphite oxide iron sulfate hydrate intercalating matter; and preparation of the graphene-based gamma-FeO2O3 composite material photocatalyst. The graphene-based gamma-FeO2O3 composite material photocatalyst prepared by the preparation method disclosed by the invention has high carrier transmission rate, large specific surface area and low energy gap, so that the photocatalyst has extremely high activity of photocatalytic degradation of organic matters. The photocatalytic activity of the photocatalyst disclosed by the invention is over 86% higher than that of pure gamma-FeO2O3 particles. The photocatalyst has good circular stability, can be repeatedly used for many times, and does not cause secondary pollution in the photocatalytic degradation process.

The invention discloses a cobalt-free precursor for a lithium ion battery, the chemical formula of the precursor is NixMn1-x (OH) 2, 0.75 < = x < = 0.85, the particle size is 12-18 [mu] m, and the cross-sectional morphology of the particles is divergent from the center of a circle to the circumference. The invention also discloses a preparation method of the cobalt free precursor for lithium ion battery and a positive electrode material. According to the preparation method disclosed by the invention, the core-shell cobalt-free precursor with a divergent structure can be obtained, the nickel content of the inner core is higher than that of the outer shell, and the manganese content of the inner core is lower than that of the outer shell, so that a structure of which the inner core is high-nickel and low-manganese and the outer shell is high-manganese and low-nickel is formed; the high nickel of the inner core can improve the specific capacity of the material, the high manganese of the outer shell can provide smooth transition of Li < + >, and the divergent structure of the inner core particles provides a Li < + > transmission channel to accelerate de-intercalation of Li < + > and improve the rate capability of the material, so that the problem of poor rate capability caused by Co deficiency is solved; higher specific capacity, cycling stability and thermal stability can be obtained by using the precursor to prepare the positive electrode material.

The invention relates to a layered lithium-rich manganese oxide positive electrode material suppressing capacity/voltage attenuation during a circulation process effectively and a preparation method therefor and an application thereof. The preparation method of the layered lithium-rich manganese oxide positive electrode material comprises the following steps of: during a preparation process of a precursor of the layered lithium-rich manganese oxide positive electrode material of a lithium ion battery, adding the raw material precursor of LiNiO2; and performing high temperature heat treatment to obtain a layered lithium-rich manganese oxide composite positive electrode material. The Ni element in the layered lithium-rich manganese oxide positive electrode material can effectively suppress the migration of transitional metal elements during the circulation of the layered lithium-rich manganese positive electrode material and suppress the formation of a spinel phase, thereby effectively suppressing the capacity/voltage attenuation during the circulation process. The positive electrode and the lithium ion battery that use the material belong to the technical field of energy materials and energy conversion. The material used as the positive electrode material of the lithium ion battery has the advantages of high energy density, cycling stability, and good rate capability.

The invention discloses a graphene/functionalized metal-organic framework material composite intercalation as well as a preparation method and application thereof. The graphene/functionalized metal organic framework material composite intercalation is prepared by taking a metal-organic framework material and graphene in a certain ratio as main bodies, and is placed on the cathode side of a non-polar diaphragm of a lithium-sulfur battery, so electrolyte absorption and lithium ion diffusion can be promoted, interface impedance is effectively reduced, polysulfide is adsorbed to limit the diffusion of the polysulfide, the shuttle effect of the polysulfide is inhibited, and the loss of active substances is reduced; the assembled lithium-sulfur battery is high in capacity and slow in attenuationat high multiplying power and shows excellent cycling stability and multiplying power performance; and the intercalation can be widely applied to lithium-sulfur batteries.

The invention discloses a composite electrode material, a preparation method and a super capacitor. The preparation method of the composite electrode material comprises: after carbon cloth loaded withCo-MOF is calcined, obtaining carbon cloth loaded with Co<3>O<4> nanosheets; and taking the carbon cloth loaded with the Co<3>O<4> nanosheet as a working electrode, and carrying out electrodepositionin an electrolyte to obtain the composite electrode material. The electrolyte comprises aniline and 0.8 to 1.2 M of sulfuric acid, and the electro-deposition time is 10 to 14 minutes. The compositeelectrode material provided by the invention is the composite electrode material in which carbon cloth is loaded with core-shell structure nanosheets, wherein the core is Co<3>O<4> nanosheets, and theshell is made from polyaniline. According to the composite electrode material disclosed by the invention, the Co<3>O<4> nanosheets obtained in preparation and the core-shell structure nanosheets in aproduct uniformly grow on carbon cloth, and collapse is avoided; and the composite electrode material can be directly used as a working electrode, is high in specific capacitance, good in cycling stability and large in specific surface area, and can improve the utilization rate of active substances.

The invention discloses a preparation method of a sodium ion transition metal oxide positive electrode material, which comprises the following steps: S1, mixing: taking out stoichiometric sodium acetate trihydrate, manganese acetate tetrahydrate, nickel acetate tetrahydrate, cobalt acetate tetrahydrate, magnesium acetate, zinc acetate dihydrate and citric acid, and conducting uniform dissolving inquantitative water, then fully conducting stirring and dissolving, transferring the solution into a water bath kettle, and continuously conducting stirring to a gel state. According to a prepared sodium ion positive plate, the Zn element is doped in the sodium ion positive plate, so that the Jahn-Teller effect of Mn<3+> ions can be effectively weakened, and the structural stability of the positive electrode material in the circulation process is better improved, so that the cycle life of the prepared material and improving the rate capability of the prepared material is effectively prolonged,the Zn doping amount can be further increased, the cycling stability of the material can be continuously improved, the material has excellent cycling performance and rate capability in use, the positive electrode material can effectively promote the practical application of the sodium ion battery, and the practicability is relatively high.