942results about How to "Alleviate volume expansion" patented technology

The invention discloses a silicon-carbon composite material, a lithium ion battery, and a preparation method and application of the silicon-carbon composite material. The preparation method of the silicon-carbon composite material comprises the steps: uniformly mixing silicon powder and silicon monoxide powder, then mixing with a solution containing an organic carbon source dispersant, and performing wet-process ball milling to obtain a slurry; uniformly mixing the slurry, graphite and a conductive agent, and performing spray drying to obtain spherical-like particles, wherein graphite is synthetic graphite and/or intermediate-phase graphite; mixing the spherical-like particles and asphalt, performing cladding processing under the inert atmosphere to obtain a cladded material; and then performing carbonizing processing to obtain the silicon-carbon composite material, wherein silicon powder, silicon monoxide powder, graphite and asphalt respectively accounts for 5-15%, 3-10%, 45-75% and 5-40% by weight of the sum of the above materials, and the organic carbon source dispersant and the conductive agent both accounts for 0.1-2% by weight of the sum of silicon powder, silicon monoxide powder and graphite. The silicon-carbon composite material has relatively good cycle performance, and can be directly used as a cathode material of the lithium ion battery. The preparation method is simple in technology, low in cost and applicable to industrial production.

The invention relates to a silicon-carbon composite negative pole material preparation method and a lithium ion battery. The preparation method comprises putting nanometer silicon and graphite micro-powder into a ball mill, carrying out ball milling uniform dispersion in an organic solvent environment, carrying out vacuum drying, putting the dried mixture and asphalt into a cone-type mixer, carrying out coarse mixing, putting the mixed powder subjected to coarse mixing into a mechanical fusion machine, carrying out mechanical fusion, carrying out heat treatment in an inert gas protective atmosphere and carrying out cooling to obtain the silicon-carbon composite negative pole material. The preparation method carries out asphalt softening coating on nanometer silicon so that silicon particle and electrolyte direct contact is avoided, a capacity reduction rate is delayed, a lithium ion diffusion path is shortened, an electrode material electron conduction loss is avoided, and first charge-discharge efficiency, a charge-discharge electric capacity and cycle performances are improved. Before coating, nanometer silicon is dispersed through graphite micro-powder so that it is avoided that in asphalt coating, nanometer silicon aggregation causes local capacity excess and nanometer silicon is uniformly dispersed.

In an electronic device which realizes high-temperature-side solder bonding in temperature-hierarchical bonding, a bonding portion between a semiconductor device and a substrate is formed of metal balls made of Cu, or the like, and compounds formed of metal balls and Sn, and the metal balls are bonded together by the compounds.

The invention discloses a preparation method of a silicon carbon negative electrode material for a lithium ion battery. The preparation method comprises the following steps: high-energy ball milling, organic carbon coating, high-temperature carbonization and micro-oxidation, wherein the micro-oxidation step is carried out after the high-energy ball milling step and before the organic carbon coating step, and is carried out at least once after the high-temperature carbonization step. The previous and/or subsequent micro-oxidation treatment can ensure that a SiO2 layer is oxidized on the Si surface, and play a role of oxidation and pore-forming on graphite and pyrolytic carbon; a SiO2 electrochemical inert layer inhibits the volume expansion of Si to a certain extent, while the porous structure can relieve the volume expansion of Si to a certain extent, thereby improving the cyclic performance of the silicon carbon negative electrode material.

The invention discloses a silicon-carbon composite anode comprising a silicon source and a carbon source, wherein silicon source is monatomic silicon, the particle size distribution is 100 nm to 80 microns, and the mass of the silicon source accounts for 10-80% of the total mass of the silicon-carbon composite anode; the carbon source comprises a carbon anode material and a conductive agent, the carbon anode material is one or more of carbon fiber, graphite and mesocarbon microbead, and the mass of the carbon anode material accounts for 10-90% of the total mass of the carbon source. According to the silicon-carbon composite anode disclosed by the invention, one-step coating forming, hot pressing flaking, carbonization treatment and high-temperature calcination are carried out on anode slurry prepared by mixing the silicon source with the carbon source, so as to guarantee that the silicon material is effectively dispersed in a carbon skeleton, the prepared silicon-carbon anode can effectively relieve the volume expansion of the silicon material in charging and discharging processes in a circulation process and guarantee excellent cycle performance of the battery; the silicon-carbon composite anode is prepared by one-step coating forming, and no current collector is needed, so that the production process is simplified and the battery is guaranteed to have high energy density; meanwhile, the invention further provides a lithium ion battery containing the silicon-carbon composite anode.

A silicon oxide material is obtained by cooling and precipitating a gaseous mixture of SiO gas and silicon-containing gas and has an oxygen content of 20-35 wt %. Using the silicon oxide material as a negative electrode active material, a nonaqueous electrolyte secondary battery is constructed that exhibits a high 1st cycle charge/discharge efficiency and improved cycle performance while maintaining the high battery capacity and low volume expansion of silicon oxide.

The invention relates to a preparation method of a porous silicon/graphite/carbon composite negative electrode material for a lithium-ion secondary battery. A silicon source of the composite materialis natural mineral soil: namely kaolinite, montmorillonite, mica powder, wollastonite, vermiculite powder, pumice powder and coal gangue. The silicon source is reduced into elemental silicon by usinga metal element or alloy powder and anhydrous metal chloride under a mild condition, and the reduced porous silicon, graphite and an organic carbon source are subjected to high-energy ball mill mixing. The reduction temperature is low, the inherent pore structure of the natural mineral soil is effectively reserved and the prepared silicon material has relatively high specific surface area and abundant pores and has excellent electrochemical properties. Volume expansion can be effectively relieved through the inherent pore characteristic of the natural mineral soil; and the prepared composite material has higher charge-discharge capacity and stability. Especially the kaolinite is wide in source and low in price, so that the preparation cost of the battery material is greatly reduced. The porous silicon/graphite/carbon composite negative electrode material is friendly to environment, simple in preparation method, instrument and equipment and suitable for industrial production.

The invention relates to the field of preparation of a lithium ion battery, and particularly discloses a preparation method of a silicon dioxide carbon composite negative electrode material. The method comprises the following steps of (1) mixing halloysite with an organic carbon source in the presence of a solvent, and removing the solvent to acquire a solid product; and (2) roasting the solid product in an inertia atmosphere. The invention also provides a carbon nanotube/nitrogen modification method of the silicon dioxide carbon composite negative electrode material. The silicon dioxide carbon composite negative electrode material and the carbon nanotube/nitrogen modified silicon dioxide carbon composite negative electrode material, obtained according to the preparation methods provided by the invention, have relatively high cycle stability and discharge specific capacity, and are expected to be novel negative electrode materials used at a large scale.

The invention discloses a high-capacity carbon-silicon negative electrode active material and preparation and application methods thereof. The high-capacity carbon-silicon negative electrode active material achieves a specific capacity of 800-1500 mAh/g and is formed by mixing carbon-silicon materials and graphite materials, wherein the carbon-silicon materials are microspherical particles prepared by performing ball milling spray-drying and thermal treatment processes on nanosilicon, crystalline flake graphite, carbon nanotubes and a carbon source, the nanosilicon is dispersed on the surfaceof the crystalline flake graphite, the carbon nanotubes are inserted into pores formed between the carbon nanotubes and the crystalline flake graphite, pyrolytic carbon of the carbon source is coatedon the surface of the nanosilicon and the surface and pores of the spherical particles formed by the nanosilicon, the crystalline flake graphite and the carbon nanotubes; the weight of silicon-carbonmaterials is 25%-80% of the total weight of the high-capacity carbon-silicon negative electrode active material. When uniformly mixed with conducting agent and bonding agent, the high-capacity carbon-silicon negative electrode active material can be coated or deposited onto copper foils, foamed nickel, foamed copper or carbon fiber paper as the negative electrode of a lithium ion battery. The preparation method of the high-capacity carbon-silicon negative electrode active material is simple in process, low in cost, applicable to amplified preparation of long-circulation carbon-silicon materials.

The invention discloses a preparation method of a nitrogen-doped carbon material. The carbon material has a mesoporous structure and is doped with nitrogen, and the doping content of the nitrogen in the carbon material is controllable; a composite of the carbon material is modified by the carbon material; and the preparation method selects egg white as a raw material to form the nitrogen-doped carbon material through high-temperature calcination and carbonization in the inert atmosphere, and comprises steps as follows: (1), an egg white solution is taken as a solvent for material composition; (2), the egg white is steamed in boiling water and forms tin dioxide jelly similar to yellow cake; and (3), calcination is performed in the inert atmosphere to obtain the nitrogen-doped carbon material. with the adoption of the method, the nitrogen-doped carbon composite material with a carbon coating structure can be prepared, and the content of the nitrogen in the carbon material is controllable; and the prepared nitrogen-doped carbon composite material is suitable for being taken as a Li-ion electrode material, and is simultaneously applicable to the fields of corrosion resistance, gas absorption and the like.