235results about How to "Inhibition of volume change" patented technology

The invention provides transient devices, including active and passive devices that physically, chemically and/or electrically transform upon application of at least one internal and/or external stimulus. Incorporation of degradable device components, degradable substrates and/or degradable encapsulating materials each having a programmable, controllable and/or selectable degradation rate provides a means of transforming the device. In some embodiments, for example, transient devices of the invention combine degradable high performance single crystalline inorganic materials with selectively removable substrates and/or encapsulants.

The invention discloses a spherical porous silicon/carbon composite material as well as a preparation method and application thereof. The spherical porous silicon/carbon composite material is structurally characterized in that a SiOx/C matrix, graphite with small particle size and a conductive agent are dispersed in porous amorphous carbon, wherein the average particle diameter is 12-25mu m; the method comprises the following steps of carrying out first coating on a SiOx raw material with powder pitch, and performing heat treatment so as to obtain a SiOx/C material; then performing ball milling by use of a wet method so as to reduce the particle diameter of powder, adding a carbon source adhesive, the graphite with the small particle diameter and the conductive agent, and performing high-speed dispersion, thereby obtaining pulp; and finally performing spray granulation and sintering on the pulp, thereby obtaining the final spherical porous silicon/carbon composite material. According to the invention, SiOx is dispersed in cracking carbon, the graphite and the conductive agent, so that SiOx volume expansion during a charge/discharge process is buffered, and the conductibility is enhanced; by virtue of the porous structure, the imbibition rate and cycle performance of the material can be effectively improved; by virtue of bitumencarb coating and high-heat treatment performed in advance, SiOx is prevented from being directly contacted with an electrolyte, and furthermore, the stability and first efficiency of the silicon/carbon material are improved.

The invention discloses a convenient method for preparing binder-free stannic oxide/carbon fibrofelt for a negative pole of a high-performance lithium ion battery. The method disclosed by the invention comprises the following steps: dissolving polyacrylonitrile and stannous chloride which have certain concentrations to a N'N-dimethyl formamide solution, magnetically stirring the solution of polyacrylonitrile, the stannous chloride and the N'N-dimethyl formamide solution until the solution is clarified, electrostatically spinning the solution, and finally annealing the obtained solution which is obtained at a high temperature twice to obtain Sn-SnOx uniformly loaded nanometer composite materials of the carbon fibrofelt. For a compound which is prepared by the method disclosed by the invention, since the electrostatic spinning method is adopted, nanometer particles of metal-metallic oxide are uniformly dispersed into buffer substrate carbon fiber, and the circulation specific capacity and the stability of materials for the negative pole of the lithium ion battery are effectively improved. The preparation technology disclosed by the invention has the advantages that the operation is simple, the cost is low, the efficiency is high, the large-scale and industrial production is easy to realize, and the application range is broad.

The invention discloses a silicon-nitrogen doped carbon-nitrogen doped graphene composite material. The silicon-nitrogen doped carbon-nitrogen doped graphene composite material is formed by graphene oxide, a nitrogen-containing carbon source and silicon, wherein a mass ratio of graphene oxide to the nitrogen-containing carbon source to silicon is 1-4:2:2-6; and nitrogen doped carbon with a core-shell structure is obtained through a solution mixing process and a high temperature charring process, and coats silicon particles, and the nitrogen doped carbon coated silicon particles are uniformly inlaid in nitrogen doped graphene interlayer. A preparation method of the composite material comprises the following steps: adding a nitrogen-containing carbon source solution into a silicon dispersion, and carrying out stirring ultrasonic treatment; adding a graphene oxide dispersion solution to the above obtained mixed solution in the ultrasonic process; and carrying out stirring heating, evaporation pulping, freeze drying and high temperature charring in order to obtain the silicon-nitrogen doped carbon-nitrogen doped graphene composite material. The nitrogen-containing carbon source is used to form a carbon layer on the surface of silicon particles and realize nitrogen doping of the carbon layer and graphene, the preparation process is simple, controllable and environmentally-friendly, and the composite material greatly improves the integral electrochemical performances.

The invention relates to an anode material for a lithium ion battery, which is a complex formed by an organic compound and a metal or metalloid material. The invention also provides a preparation method of the anode material, comprising the steps of: uniformly mixing the metal or metalloid material and the organic compound under an atmospheric pressure within a temperature range of 0-25 DEG C andadding an oxidizing agent to obtain the required complex of the organic compound and the metal or metalloid material. According to the invention, the complex compound can be directly used as the anode material of a lithium ion battery and can be also mixed with other lithium storing materials in a proportion of 1-99 wt%; the anode material has very high lithium storing capacity and good circulating performance without being subjected to a plurality of circulations, can improve the electrical contact and adhering performances among electrode material particles as well as between an electrode material and a current collector, can effectively restrain the volume change of the electrode material in a charge-discharge process, can slow down the capacity attenuation of the electrode material, and can prolong the circulating life of the constituted battery.

Provided are a servo measuring testing system and method for coal sample gas adsorption and desorption. The system comprises a gas supply device, a vacuumizing device, a gas adsorption device, a gas desorption measurement device and an electric control device; the gas supply device comprises a high-pressure gas tank and a gasing tank; the vacuumizing device comprises a vacuum pump and a vacuum meter; the gas adsorption device comprises a coal sample tank, and the gas desorption measurement device comprises a water storage container, a water collection container, an electronic balance, a servo motor, a fixed support and a water guide pipe. According to the servo measuring testing system and method for coal sample gas adsorption and desorption, volume measurement of desorbed gas is converted into volume measurement of liquid water, test operation is easy and convenient, test data is accurate, and real-time precise automatic collection and real-time display of the test data are achieved; in addition, it is guaranteed that the gas desorbed from a coal sample is under the condition of one atmospheric pressure, and a more reliable data basis is provided for researching the coal-mass gas adsorption and desorption rule.

A method for cycling a sulfur composite lithium ion battery includes a step of charging and discharging the sulfur composite lithium ion battery at a first voltage range between a predetermined highest voltage and a predetermined lowest voltage. The lithium ion battery includes an electrode active material. The electrode active material includes a sulfur composite. The step of charging and discharging satisfies at least one conditions of (1) and (2): (1) the predetermined lowest voltage of the first voltage range is larger than a discharge cutoff voltage of the sulfur composite; and (2) the predetermined highest voltage of the first voltage range is smaller than a charge cutoff voltage of the sulfur composite. A method for using a sulfur composite as an electrode active material of a lithium ion battery is also disclosed.

Disclosed is a battery casing, comprising one or more sub-layers as constitutional elements, wherein at least one region selected from the group consisting of a surface of the casing and the sub-layers of the casing is coated partially or totally with a metal having a grain size of 50 nm or less. A battery comprising the same casing is also disclosed. The casing efficiently inhibits degradation of the safety of a battery, caused by internal or external factors, and thus provides a battery with excellent safety.

The present invention provides a method for manufacturing a negative electrode material for a nonaqueous electrolyte secondary battery, which includes the steps of: preparing silicon nanoparticles; manufacturing the silicon-carbon composite material that contains the silicon nanoparticles and a carbonaceous material; and heat-compressing the silicon-carbon composite material. As a result, there is provided a negative electrode material for a nonaqueous electrolyte secondary battery, which has a high capacity and excellent initial charge/discharge efficiency and cycle characteristics and a method for manufacturing the same, and a nonaqueous electrolyte secondary battery that uses the negative electrode material for a nonaqueous electrolyte secondary battery.

The invention relates to a battery cathode material and a preparation method thereof. The cathode material at least comprises the active material elemental silicon and reduced graphene oxide, and also includes polyaniline. Also, the elemental silicon has the double cladding layer of polyaniline and reduced graphene oxide. On the one hand, the special internal structure of polyaniline can well inhibit huge volume change of silicon particles in a charge-discharge process, thus improving the cycle performance of the battery; and on the other hand, both polyaniline and graphene have excellent electrical conductivity, and can significantly improve the charge-discharge capacity of the material. The invention also relates to a battery cathode and a battery containing the cathode material. The battery cathode and the battery provided by the invention have high charge-discharge capacity and good cycle performance, thus being suitable for various mobile electronic equipment.

Melamine resin pellets are obtained through one-step condensation of melamine and formaldehyde, the melamine resin pellets used as templates are coated with polypyrrole by using pyrrole as a nitrogensource and a carbon source and ammonium persulfate as a catalyst; the melamine resin pellets are gradually decomposed in the roasting process by controlling roasting to obtain nitrogen-doped porous hollow carbon spheres; and finally, the material is used in a lithium ion battery negative electrode. By using the melamine resin pellets instead of traditional silicon dioxide pellets, the problem of environmental pollution caused by etching of a silicon dioxide hard template with use of toxic reagents such as hydrofluoric acid in a traditional hard template method is avoided. Because the melamineresin pellets can generate a large amount of gas in the decomposition process, pores can be further formed in the pore walls of the hollow carbon spheres. Because the material is uniform in morphology, large in specific surface area and of a hollow structure, volume expansion can be relieved, and high specific capacity and cycle stability are shown in the lithium ion battery.

The present invention belongs to the technical field of lithium ion batteries and in particularly relates to a composite anode material for a lithium ion battery. The composite anode material for a lithium ion battery comprises an anode active material and a coating layer coating the surface of the anode active material, wherein the anode active material is at least one selected from the group of Si, SiO_x or a silicon alloy, the coating layer, which is a polymer of a network structure, accounts for 1-20% by mass of the anode material.

The invention discloses a preparation method of a hydro-thermal coupling spray pyrolysis MnO2/graphene electrode material, belonging to the technical field of electrode materials for energy storage systems. The preparation method comprises the following steps: uniformly mixing graphene oxide (GO) prepared by using a Hummer method with an aqueous solution of bivalent manganese salt and a doped metal ion compound, adding a dispersing agent, an oxidant and a surfactant, and ultrasonically dispersing for a certain period of time; putting the mixed solution into a hydrothermal kettle, adjusting the temperature, and keeping for a certain period of time; filtering and washing a reaction product to obtain a precursor; adding the dispersing agent and the surfactant into the precursor, uniformly stirring for mixing, and adjusting the solid-liquid ratio, inlet temperature and outlet temperature to perform spray pyrolysis in order to obtain a metal ion-doped MnO2/graphene nanometer composite electrode material. According to the nanometer composite electrode material prepared by using the method, components are uniform and the batch stability is high.

The invention discloses a ternary multilevel multi-dimensional structure composite material and a preparation method thereof. The excellent electrochemical comprehensive performance can be exerted by utilizing the remarkable synergistic effect and unique multilevel multi-dimensional structure. The composite material is formed by TiO2 of a low-dimensional nano structure and second-phase high-specific-capacity metal oxide as well as two-dimensional micrometer (x-y plane direction) high-conductivity plain graphene. Drive force for lowering the total surface free energy of the solution system is utilized to uniformly load and compactly combine TiO2 of the nano structure and high-specific-capacity metal oxide to an exposed surface of the plain graphene nanosheet by virtue of a tetrahydrofuran solution mixing method. The ternary multilevel multi-dimensional structure composite material effectively integrates the remarkable function of each ingredient, including excellent circulating property and outstanding safety of TiO2, high specific capacity of the second-phase metal oxide, and good conductivity of the plain graphene.

A gas generating composition which is excellent in a combustion efficiency and a gas output and in which amounts of residues generated are reduced in the combustion is obtained.A gas generating composition comprising (a) 5 to 40% by weight of at least one high polymer selected from the group consisting of a polyacrylic derivative resin, a polyacetal, a urea resin, a melamine resin, a ketone resin and a cellulose-based high polymer, and (b) 60 to 95% by weight of ammonium nitrate or phase-stabilized ammonium nitrate. It is suitable as a gas generating agent for an air bag of automobiles.

The invention discloses a Fe3O4-graphite composite nanometer material and a preparation method thereof and application of the Fe3O4-graphite composite nanometer material in a lithium ion battery, and belongs to the technical field of lithium ion battery electrode materials. The preparation method includes the following steps: using graphite and potassium ferrate as raw materials, and then adding zirconium balls in the raw materials; at a speed of 300-500rpm, conducting ball milling by a planetary ball mill for 12-60 hours; conducting product separation, filtration, washing and drying to obtain the Fe3O4-graphite composite nanometer material. The material is applied in a lithium ion battery cathode and has excellent electrical properties; under the condition of the current density of 200 mA g<-1>, the material can keep a reversible capacity of 970 mAh g<-1> after circulation for 100 turns, the reversible capacity reaches 1132 mAh g<-1)> after circulation for 250 turns, and under the condition of large current density (1000 mA g <-1>), the reversible capacity can still keep at about 650 mAh g<-1> after circulation for 200 turns.

The invention discloses a surface-modified silicon-carbon composite and a preparing method and application thereof. The method includes the steps of firstly, conducting high-temperature treatment on commercial raw materials containing silicon oxide, and conducting pickling to clean away impurities to obtain silicon oxide; secondly, conducting magnesium thermal reduction reaction on the silicon oxide to obtain nanometer silicon, synchronously conducting carbon wrapping to obtain a silicon-carbon nanometer material, and combining the nanometer silicon carbon and fluoride through ball-milling toobtain the silicon-base composite. Compared with the prior art, the method is simple in process, low in energy consumption and beneficial for industrial production. The silicon-carbon composite modified by the prepared surface fluoride has high capacity, high primary coulombic efficiency and excellent circulating performance.

The invention relates to a preparation method of a porous metal doped lithium manganate/graphene lithium battery positive electrode material. The method includes the steps that 1, a sol-gel method is adopted for preparing a precursor of porous LiM0.2Mn1.8O4, and the precursor is put into a muffle furnace to be calcined at constant temperature to obtain porous LiM0.2Mn1.8O4; 2, graphene oxide is taken and added into deionized water to prepare a graphene oxide solution with the mass concentration of 0.05-0.1 g/mL; 3, porous LiM0.2Mn1.8O4 is put into the graphene oxide solution, the mixture is subjected to magnetic stirring, ultrasonic dispersion and drying and then transferred into a tube furnace to be calcined at constant temperature, and the porous metal doped lithium manganate/graphene lithium battery positive electrode material is obtained. Compared with the prior art, the preparation method is simple, and the raw materials are easy to get; the prepared material is good in crystallinity and uniform in particle size, and the size is about 30 nm; serving as a lithium battery positive electrode material, the prepared material is good in electrochemical stability, high in specific discharge capacity and good in rate performance and cycle performance.

The invention discloses a preparation method of a nanosheet self-assembled three-dimensional nano flower tin sulfide/graphitized carbon nitride lithium ion battery anode material. Melamine is kept at450-650 DEG C for 2-6 hours, is naturally cooled to room temperature, is ground for prepare use, and is dispersed in ethanol to obtain a suspension, the suspension is centrifuged and washed several times with deionized water and absolute ethanol, vacuum drying is conducted to obtain a product g-C3N4, the product g-C3N4 is dissolved in the deionized water, after stirring, the product g-C3N4 is ultrasonically dispersed to form a suspension A, PVP is added to the suspension A, stirring is conducted until the product g-C3N4 is completely dissolved to form a solution B, TAA and SnCl4 2H2O are addedto the solution B, stirring is uniformly conducted to form a solution C, the solution C is subjected to a microwave hydrothermal reaction, after the reaction is completed, a precursor is obtained, the precursor is centrifuged and washed several times with the deionized water and the absolute ethanol, and vacuum drying is conducted to obtain a nanosheet self-assembled three-dimensional nano flowerSnS2/g-C3N4 battery material.