31results about How to "High first reversible capacity" patented technology

The invention relates to a carbon-carbon multi-component negative electrode material. The carbon-carbon multi-component negative electrode material is mainly composed of flexible graphite, nanometer silicon and amorphous carbon which respectively account for 30-60%, 30-50% and 10-30% based on mass percent, the amorphous carbon is obtained through high-temperature pyrolyzation of an organic carbon source, and the flexible graphite is obtained by applying pressure to expanded graphite. A preparation method of the product comprises the steps of: firstly, preparing an expanded graphite/silicon-silicon dioxide/carbon composite negative electrode material through high-temperature pyrolyzation; secondly, pouring the expanded graphite/silicon-silicon dioxide/carbon composite negative electrode material into a mould and applying pressure to obtain a flexible graphite/silicon-silicon dioxide/carbon composite negative electrode material; thirdly, processing silicon dioxide to obtain a flexible graphite/silicon/carbon composite negative electrode material through etching by a corrosive liquid; and finally, using asphalt to permeate a gap inside the flexible graphite/silicon/carbon composite negative electrode material in a protective atmosphere, and obtaining the product after high-temperature heat treatment and repetition. The carbon-carbon multi-component negative electrode material has the advantages of high capacity, high coulombic efficiency, good cycle performance, structure stability, high reversible capacity and the like.

The invention discloses a preparation method of spherical graphite with a median diameter of 11 to 16 mu m. A five-level powder refining machine set consisting of an air-flow vortex powder refining machine and a cyclone separator is sequentially connected with a fourteen-level nodulizing machine set consisting of an air-flow vortex nodulizing machine and a nodulizing classifier in series; the graphite material enters from the first powder refining machine set and then flows through the five powder refining machine sets and the fourteen nodulizing machine sets in turn and finally out of the last nodulizing machine set; and by refining and nodulizing the powder, the spherical graphite product is obtained. The tap density of the obtained spherical graphite is 1.07-1.10 g/ml, and the number of openings on the surface of the graphite powder is 9-80 per mu m. The sphericity of the product is high, the electrochemical performance is obviously improved, the battery capacity, the standby time and the service life are effectively increased, and no overheat happens; moreover, the preparation method can improve the yield by over 75 percent, lower the cost by 38 percent, save the power consumption by 42 percent and realize the dust recovery rate up to 100%.

The invention discloses a preparation method for a high-performance modified graphite negative electrode, and in particular discloses a preparation method for a graphite negative electrode of a lithium ion battery. The preparation method mainly comprises the following steps of: conducting procedures of liquid-phase even mixing, drying, roasting, screening and the like to water-soluble phenol-formaldehyde resin, an aluminum source and graphite negative electrode material to be modified to prepare a graphite negative electrode which is modified jointly by pyrolytic carbon and aluminum oxide, wherein the surfaces of the pyrolytic carbon are coated with phenolic resin. The modified graphite negative electrode material has the characteristics of being high in reversibility specific capacity, high in first-time charging and discharging efficiency, long in recycling life and good in safety property. The modified technique is simple to operate, low in cost, and obvious in modification effect.

The invention discloses a core-shell structure multi-component composite material, a preparation method thereof and a lithium ion battery comprising the multi-component composite material. The multi-component composite material comprises a graphite core and an outer shell coating the surface of the core, and the outer shell comprises a chain-shaped hard carbon layer and a soft carbon layer from the inside to the outside. The method comprises the following steps: 1) mixing an amorphous carbon precursor, a solvent and a surfactant to obtain a liquid phase first precursor; 2) mixing the core material graphite and the chain polymer material, and carrying out surface modification treatment to obtain a second precursor; 3) adopting a second precursor and the first precursor of the liquid phase to prepare a composite third precursor through coating treatment, and carry out carbonization to obtain a core-shell structure multi-component composite material. The method of the invention is simple,the process is short, the cost is low, the environment is friendly and pollution-free, and the obtained multi-component composite material has the characteristics of high compaction density, high first reversible capacity and first coulomb efficiency, and excellent processing performance and low temperature performance.

The invention discloses a lithium ion battery cathode material carbon microsphere and a preparation method thereof. The preparation method comprises that in the presence of a catalyst, through optimization of condition factors such as a temperature in a reaction vessel system, time and carbon source kinds, a carbon microsphere intermediate having controllable morphology is obtained, and the carbon microsphere intermediate is sintered into a carbon microsphere sample in an inert atmosphere in a tubular furnace. The preparation method ingeniously and efficiently utilizes raw materials, fills the gap of development of a nano-material in lithium ion battery cathode material preparation, enriches a material preparation method, and effectively solves the problem that the existing carbon cathode material of a lithium ion battery has a high first irreversible capacity and poor rate discharge performances.

The invention discloses a nano silicon/carbon composite material, a preparation method and a lithium ion battery comprising the same as a negative electrode material. The method comprises: 1) mixing nano silicon, a coupling agent, a conjugated diene, and an olefin monomer; 2) mixing the resulting mixture with water, an emulsifier, an initiator, and a co-surfactant, using a microemulsification method to prepare microemulsion, and using a microemulsion polymerization method to form a crosslinked polymer wrapping material on the surface of the nano silicon; and 3) performing demulsification and carbonization to obtain the nano silicon/carbon composite material. In the nano silicon/carbon composite material, a nano-silicon core and an amorphous conductive carbon layer are very tight and stableto combine, the disadvantages that a general carbon layer and a silicon material are not uniformly wrapped and not tightly combined are solved, the volume expansion of the silicon material during thecycle is suppressed, and the battery prepared from the composite material has excellent cycle performance, and has excellent rate performance and low volume expansion effect.

The invention belongs to the field of new energy materials, and relates to a silicon-carbon composite negative electrode material, a negative electrode plate, a preparation method thereof and a lithium-ion battery. The preparation method of the silicon-carbon composite negative electrode material comprises the following steps: S1, dispersing phenol and/or aminophenol, formaldehyde and a silicon precursor material into an alcohol-amine mixed aqueous solution, violently stirring and reacting at 20-90 DEG C for at least 20 minutes, carrying out solid-liquid separation, and drying to obtain a silicon dioxide/phenolic aldehyde compound with a fractal structure; and S2, roasting the silicon dioxide/phenolic aldehyde compound in the presence of magnesium powder and/or aluminum powder to obtain the silicon-carbon composite material with the fractal structure. When the silicon-carbon composite material is used as a lithium-ion battery negative electrode material, the failure caused by volume change in the charging and discharging process can be well overcome, a good conductive network is maintained, the volume expansion is reduced, the first reversible capacity and the first coulombic efficiency are improved, the first cycle capacity loss is reduced, and the cycle stability is improved.

The invention provides a preparation method of a copper-coated porous silicon composite material and a composite electrode for a lithium ion battery. The preparation method comprises the following steps of S1, preparing a precursor containing silicon dioxide and copper oxide; and S2, treating the precursor by adopting a magnesiothermic reduction method so as to reduce silicon dioxide and copper oxide to form a porous silicon and copper coating layer. By coating copper on the surface of porous silicon, the generation of an SEI film can be effectively inhibited, and meanwhile, the conductivity of the above composite material can be improved, so that the higher first reversible capacity and the coulombic efficiency can be obtained by taking the composite material as an electrode material. Moreover, the porous structure of silicon buffers the volume expansion, and the coating of a proper amount of copper can effectively improve the conductivity of the material and form a proper amount of silicon-copper alloy supported porous skeleton structure, so that the composite material can keep higher reversible capacity and capacity retention ratio after being used as the electrode material.

The invention discloses a TiO2 (B) negative electrode material as well as a preparation method and an application thereof; the preparation method of the TiO2 (B) negative electrode material comprisesthe following steps of S1, mixing a solvent with a titanium source, carrying out heating and refluxing, adding water, cooling, and dropwise adding acetone to obtain a white precipitate; and S2, carrying out alcohol washing and/or water washing on the white precipitate in the step S1 and then performing vacuum drying and calcining to obtain the negative electrode material, wherein the calcining adopts segmented calcining. The first reversible capacity of the prepared negative electrode material is as high as 190 mAh/ g or above, the first coulombic efficiency is higher than 82%, the capacity retention rate after being circulated for 200 cycles is 82-94%, and the negative electrode material has the advantages of high cycle performance and high specific capacity. The TiO2 (B) negative electrode material prepared by adopting a solvothermal method is high in purity, the preparation method is simple, the conditions are easy to control, the preparation period is short, the cost is low and theapplication value is high.

The invention relates to a composite negative electrode material for a lithium ion battery, and a preparation method thereof. The composite negative electrode material comprises hard carbon particles and graphite particles, the hard carbon particles and the graphite particles are uniformly dispersed, and the hard carbon particles are obtained by carrying out high temperature sintering operation, mechanical shaping operation and surface coating operation on a carbon raw material. The hard carbon particles and the graphite particles are compounded and have complementary performance advantages, so that the rate capability and the low-temperature performance of the composite material are improved, and meanwhile, the first efficiency, the high-temperature performance and the storage performance of the composite material can be ensured; and when the composite negative electrode material provided by the invention is used as a negative electrode active material of the lithium ion battery, the lithium ion battery has excellent rate capability, the raw materials are cheap, the preparation process and equipment are mature, and the composite negative electrode material is suitable for large-scale production.