395results about How to "Increased diffusion rate" patented technology

The present invention relates to a catalyst for ortho-parahydrogen conversion suitable for a wide range of low-temperature conditions and a preparation method thereof. The catalyst is a fiber magnetic catalyst FeMnOx doped with Fe atoms in an orderly manner; the base material of the catalyst is α-MnO2, the α-MnO2 belongs to the tetragonal system, the unit cell parameter is #imgabs0#, the crystal structure is composed of 2×2 octahedral chains with shared edges, the XRD characteristic diffraction peaks are 2θ=12.8°, 18.1°, 25.7°, 37.5°, 49.8°, 56.3°, and the specific surface area measured by the BET test method is 100-150m 2 / g, and transmission electron microscopy shows that its microstructure is a fibrous structure with a diameter of 2 to 5nm and a length of 100nm to 500nm; when the catalyst is used for the ortho-parahydrogen conversion reaction, the ortho-parahydrogen conversion efficiency is more than 95%, and the catalyst life is more than 1400h; the wide range of low temperature conditions is 23K-77K. The coordination of Fe atoms with lattice oxygen in α-MnO2 can effectively avoid the deactivation of the catalyst caused by the change of the valence state of the metal component, thereby enhancing the stability and life of the catalyst, and is suitable for industrial-scale production.

The invention belongs to but not limited to the technical field of electrode materials, and particularly relates to a high-tap-density lithium nickel manganese oxide positive electrode material, a preparation method and a lithium ion battery, the chemical general formula of the high-tap-density lithium nickel manganese oxide positive electrode material is LiNi < 0.5-x > Mn < 1.5-y > M < x > N < y > O < 4 >, 0.1, 0 < = y < lt >; 0.1, M and N are doping elements and comprise one or more of Mg, Co, Al, Zr, W, Sb, Ta and Ti; the material is micron-sized spherical secondary particles formed by stacking and aggregating nano-sized octahedral primary particles, and is uniformly dispersed without agglomeration; the spherical secondary particles are formed by mixing spherical secondary particles with large and small particle size distribution, and the average particle size range of the large particles is 3lt; d < 50lt >; the average particle size range of the small particles is 1lt; d < 50lt >; 2 [mu] m.

The invention provides an amine low-water-content absorbent for capturing carbon dioxide and application of the amine low-water-content absorbent. The amine low-water absorbent comprises, by mass, 20%-50% of an absorbent main agent, 35%-70% of an auxiliary solvent and 2%-20% of water, and the range of a solvent effect factor delta of the amine low-water absorbent is 0.28-0.32. According to the method, the composition of the water-less absorbent is screened and optimized through a solvent effect factor formula, the amine water-less absorbent which is easy to desorb, low in regeneration energy consumption and low in viscosity characteristic is obtained, and wide application of the amine water-less absorbent in a carbon capture technology is promoted.

The embodiment of the utility model discloses a secondary battery and a battery pack, the secondary battery comprises an electrode roll formed by winding a first pole piece, a diaphragm and a second pole piece, and the diaphragm is arranged between the first pole piece and the second pole piece; one of the first pole piece and the second pole piece is a positive pole piece, the other one is a negative pole piece, the first pole piece comprises a first active layer, and the second pole piece comprises a second active layer; the electrode roll is provided with a flat part and bent parts located at the two opposite ends of the flat part, at least one of the first active layer and the second active layer is provided with a first groove located in the flat part, at least one of the first active layer and the second active layer is provided with a second groove located in the bent part, and notches of the first groove and the second groove located in the same active layer face the active layer of the adjacent pole piece; in the second direction, the size of the first groove is larger than that of the second groove. By adopting the structural design, the electrolyte infiltration time of the thick-coated pole piece can be shortened, the stress of the pole piece at the bending part can be reduced, and the low-temperature performance, the rate performance and the fast-charge cycle performance of the battery can be improved.

The invention discloses a method for directly repairing and regenerating a ternary positive electrode recycled material. The method comprises the following steps: S1, disassembling a ternary retired battery; s2, sintering to remove impurities; s3, removing powder and sieving; s4, mixing with crystalline lithium salt; s5, crushing and sieving after sintering and cooling; s6, mixing with a metal oxide; and S7, sintering, cooling, removing iron, and sieving. The eutectic lithium salt is used as a lithium source for lithium supplement, so that the diffusion rate of lithium ions can be increased, the concentration of the lithium ions can be improved, the reaction temperature of lithium supplement recovery can be reduced, and the energy consumption can be reduced. The ternary lithium battery is wrapped by the metal oxide, residual lithium on the surface of the material can be utilized, a layer of fast ion conductor can be formed on the surface of the material in situ, and the residual lithium on the washed surface is removed, so that the process is shortened, the cost is reduced, the transmission rate of lithium ions can be further improved, and the rate capability of the battery is improved. And the fast ion conductor structure can isolate the contact between the electrolyte and the positive electrode material, so that side reaction is reduced, and the cycle performance is improved.

The invention belongs to the field of chemical energy materials, and discloses a modified lithium iron phosphate positive electrode material and a preparation method thereof.The preparation method comprises the steps that a lithium source, an iron source and a zinc source are added into water to be stirred and dissolved, then a phosphorus source, a network gelling agent and an initiator are added, stirring reaction is conducted, and wet gel is obtained; and pre-decomposing the wet gel, grinding and sintering to obtain the modified lithium iron phosphate positive electrode material. According to the invention, Zn is introduced into the lithium iron phosphate positive electrode material, so that the olivine structure of the positive electrode material and the purity and consistency of the lithium iron phosphate positive electrode material are ensured; and Zn is oxidized into Zn < 2 + > to be doped into a lithium iron phosphate structure, so that vacancies are formed, the lithium ion diffusion rate and conductivity of the lithium iron phosphate positive electrode material are improved, the rate cycle performance of the prepared modified lithium iron phosphate positive electrode material is stable, and excellent discharge performance and stable rate cycle performance can be kept at low temperature.

The invention discloses cobaltosic oxide, a preparation method thereof, lithium cobalt oxide, a positive pole piece and a battery, and relates to the technical field of lithium battery positive pole materials. The Dv50 of the cobaltosic oxide, the grain size D (111) of the (111) crystal face and the specific surface area BET meet the following relation: 3.33 [mu] m < 3 > / g < = # imgabs0 # < = 6.90 [mu] m < 3 > / g, wherein the Dv50 of the cobaltosic oxide is 3-20 [mu] m. The cobaltosic oxide is obtained by pre-sintering and calcining cobalt carbonate with the crystallinity of 30%-80% and the median particle size Dv50 of 3-22 [mu] m; the reaction activity of the cobaltosic oxide and a lithium source is high, the mechanical property is good, the lithium ion diffusion rate of the obtained lithium cobalt oxide is high, and the specific capacity and the first charge-discharge efficiency are relatively high.

The invention discloses an adsorption heat storage material with a multi-stage stepped pore structure and a preparation method of the adsorption heat storage material, according to the material, a metal foam matrix is combined with the multi-stage pore structure, and the storage and release efficiency of heat energy is remarkably improved. Specifically, the metal foam matrix is composed of a plurality of metal foam layers with different porosities, and the porosities are gradually increased in the heat source direction, so that the heat resistance is effectively reduced, and the diffusion of adsorbate is accelerated. The adsorbent coating is coated with an adsorption material mixture containing a template agent, and is subjected to drying and roasting treatment to form a multi-stage pore structure comprising macropores, mesopores and micropores, so that the adsorption diffusion speed and the adsorption capacity are improved. The material not only improves the heat energy storage and energy release capabilities, but also optimizes the diffusion rate of adsorbate. According to the preparation method, through simple and convenient processes such as splicing of the metal foam layer and coating of the adsorbent, the production cost is reduced, the preparation process is efficient and controllable, and wide application prospects are achieved.

The invention provides a positive pole piece, a preparation method thereof and a lithium ion battery. The positive pole piece comprises a positive current collector and a negative current collector, the first active coating is arranged on the surface of at least one side of the positive electrode current collector; the raw materials of the first active coating comprise a first main material, a first conductive agent and a low-swelling binder; the second active coating is arranged on the surface of one side, relatively far away from the positive electrode current collector, of the first active coating; and raw materials of the second active coating comprise a second main material, a second conductive agent and a high-swelling binder. Different types of binders are introduced into the first active coating and the second active coating, so that the tortuosity and porosity of the pole piece are changed, the diffusion rate of lithium ions is effectively improved, the concentration polarization of the surface layer of the pole piece is reduced, and the rate and cycle performance of the battery are remarkably improved. Particularly, the positive pole piece can achieve the goal of improving the multiplying power and the cycle performance without increasing the proportion of the conductive agent.

The invention relates to the field of lithium ion battery materials, and particularly discloses a composite positive electrode material as well as a preparation method and application thereof. The composite positive electrode material comprises a positive electrode active material and a coating material coated on the surface of the positive electrode active material, lithium iron phosphate is used as a basic raw material, and the positive electrode active material is prepared by doping rare earth elements and non-metallic elements; the surface of the positive active matter is coated with a layer of mixture which takes sulfide solid electrolyte, a conductive agent and lithium salt as raw materials, interface impedance is effectively reduced through element doping and surface coating, the interlayer spacing of the material is increased, and the diffusion rate of lithium ions is improved, so that the lithium ion battery also has good electrical properties in a wide temperature range. According to the technical scheme, the problems that in the prior art, the charging and discharging efficiency of a lithium battery is reduced in a high / low-temperature environment, the battery capacity is attenuated, and the cycle performance and the service life of the battery are affected are effectively solved.

The invention relates to the field of automobile roofs, and particularly discloses a low-odor dry ceiling and a manufacturing method thereof. The invention discloses a low-odor dry ceiling and a manufacturing method thereof. The low-odor dry ceiling comprises a non-woven fabric, a first chopped glass fiber layer, a first adsorption bonding layer, a first hot melt adhesive film layer, a polyurethane foam layer, a second chopped glass fiber layer, a second adsorption bonding layer, a second hot melt adhesive film layer and a fabric layer which are sequentially connected, each of the first adsorption bonding layer and the second adsorption bonding layer comprises high-density polyethylene powder and an adsorbent, the addition amount of the adsorbent is 15-25wt% of that of the high-density polyethylene powder, the adsorbent is silicon dioxide aerogel modified composite activated carbon, and the composite activated carbon comprises microporous activated carbon and mesoporous activated carbon in a mass ratio of (2.56-3.12): (1.12-2.05); in addition, the preparation method disclosed by the invention has the advantage of reducing odor and VOC (Volatile Organic Compounds) in the production and use processes of the automobile roof.

The invention discloses a doped iron manganese phosphate precursor, a preparation method and a lithium iron manganese phosphate positive electrode material, and belongs to the technical field of lithium ion batteries. The doped iron manganese phosphate precursor and the lithium iron manganese phosphate positive electrode material are prepared by adopting a hydrothermal method, and the grain size is refined by doping vanadium ions; the diffusion rate and the conductivity of lithium ions are improved, and the rate capability and the electronic conductivity of the positive electrode material are enhanced. And in the preparation process, quaternization modified sodium lignin sulfonate is used as a dispersing agent, so that the dispersity among particles is improved, and the problem that the electrochemical performance of the positive electrode material is reduced due to the fact that the particle size is too small and the particles are agglomerated due to vanadium doping is solved. The molecular chain of the quaternization modified sodium lignin sulfonate also contains dithio-carboxyl, so that manganese ions can be reduced and fixed while the dispersing performance of the dispersing agent is improved, the structural stability is improved, and the dissolution of manganese is reduced.

The invention discloses an iron manganese phosphate precursor and a preparation method thereof, and belongs to the technical field of lithium ion batteries, the iron manganese phosphate precursor is prepared from a phosphoric acid solution, iron powder, manganese carbonate, a surfactant and a UiO-66-NH2 / Nb2CTx composite material through chemical reaction and solid-phase reaction, the iron powder is used as an iron source, the manganese carbonate is used as a manganese source, phosphoric acid is used as phosphoric acid, and the UiO-66-NH2 / Nb2CTx composite material is used as a framework; according to the preparation method, the molar ratio of iron, manganese and phosphorus is accurately controlled, and a surfactant is used, so that the manganese iron phosphate precursor with uniform granularity, good morphology and a porous structure is obtained, the contact area between the prepared lithium manganese iron phosphate positive electrode material and an electrolyte is relatively large, and the lithium manganese iron phosphate positive electrode material has relatively high ion and electron transmission performance; and finally, the prepared lithium battery has the characteristics of high capacity and good cycle performance.

The invention discloses a preparation method of high-magnetic-induction oriented silicon steel, which comprises the following steps: sequentially heating, roughly rolling, finely rolling and coiling a plate blank obtained by continuously casting qualified molten steel to obtain a hot-rolled coil; the hot-rolled coil is sequentially subjected to normalizing treatment and cold rolling, and a cold-rolled sheet is obtained; the cold-rolled sheet is sequentially subjected to decarburization and nitriding, and the high-magnetic-induction oriented silicon steel is obtained; in the nitriding process, the nitriding temperature is 910-980 DEG C, and the dew point is 10-60 DEG C. A 910-980 DEG C high-temperature nitriding method is adopted, the diffusion efficiency of N atoms in the steel strip is improved, the uniformity of the N concentration in the thickness direction is improved, the secondary recrystallization quality and the thickness consistency of a magnesium silicate bottom layer can be improved, meanwhile, the heating rate can be properly increased during high-temperature annealing, and the high-temperature annealing time is shortened.

The invention discloses a high-capacity lithium iron phosphate positive electrode material and a preparation method thereof, and belongs to the technical field of lithium ion batteries, the lithium iron phosphate positive electrode material is compounded with a perovskite structure ion conductor; the structural formula of the perovskite structure ion conductor is AxB1-xO2-delta, and x is more than or equal to 0.2 and less than or equal to 0.8; wherein A is a rare earth element, and the rare earth element is any one of lanthanum, cerium, praseodymium, neodymium, samarium and gadolinium; b is a transition metal element, and the transition metal element is any one of chromium, manganese, iron, cobalt, nickel, copper and zinc. The perovskite structure ion conductor can provide more moving space for lithium ions, the lithium ion diffusion rate and capacity of the positive electrode material can be improved due to the high ion conductivity and lithium ion storage capacity of the perovskite structure ion conductor, the rare earth atoms can provide an additional migration channel for the lithium ions, the transition metal atoms can provide an additional electron conduction path, and the lithium ion diffusion rate and capacity of the positive electrode material can be improved. Therefore, the transmission rates of lithium ions and free electrons are matched, and the cycle performance is improved.

The invention discloses carbon nanotube modified carbon black conductive powder as well as a preparation method and application thereof, and relates to the technical field of materials. The carbon nanotube modified carbon black conductive powder provided by the invention comprises carbon black and nitrogen-containing carbon nanotubes, the nitrogen-containing carbon nanotubes grow on the surface of the carbon black in situ, and the weight ratio of the carbon black to the nitrogen-containing carbon nanotubes ranges from 10: 1 to 3: 1; the oil absorption amount of the conductive powder ranges from 210 ml / 100g to 280 ml / 100g; the resistivity range of the conductive powder is 50-90 m omega.cm; and the specific surface area of the conductive powder is 110-180m < 2 > / g. Chemical combination of the carbon black and the nitrogen-containing carbon nanotubes is achieved, when the carbon black is used as the conductive agent, a conductive path can be obtained under the condition of using a small amount, the conductivity of the carbon black is improved through introduced nitrogen, meanwhile, the use amount of the carbon black is reduced, the carbon black can be directly added into a system in a powder form and is easily dispersed into all systems, and the method is simple and easy to implement.

The invention discloses a boric acid radical substituted and modified ferric sodium pyrophosphate positive electrode material as well as a preparation method and application thereof, and belongs to the field of sodium ion batteries. The method comprises the following steps: S1, adding a boron source into an aqueous solution of ferric sodium pyrophosphate, uniformly mixing to obtain a first solution, and drying to obtain xerogel; and S2, under the protection of inert gas, roasting the xerogel so as to replace part of phosphate radicals with boric acid radicals, thereby obtaining the boric acid radical substituted modified ferric sodium pyrophosphate positive electrode material. Part of phosphate radical groups in sodium ferric phosphate pyrophosphate are replaced with borate radicals, the ion diffusion rate can be increased, the electronic conductivity of the sodium ferric phosphate pyrophosphate positive electrode material is improved, meanwhile, the specific capacity of sodium ferric phosphate pyrophosphate is improved, and the problem that in the prior art, the related sodium ferric phosphate pyrophosphate positive electrode material is poor in electronic conductivity is solved.

The invention provides platinum-rhodium alloy powder for a nitrogen-oxygen sensor electrode, a preparation method of the platinum-rhodium alloy powder and slurry for the nitrogen-oxygen sensor electrode, and the preparation method of the platinum-rhodium alloy powder for the nitrogen-oxygen sensor electrode comprises the following steps: performing chemical co-reduction on a platinum metal precursor and a rhodium metal precursor to obtain composite powder, the particle size range of the composite powder is 50-100 nm; and carrying out molten salt heat treatment on the composite powder to obtain the submicron platinum-rhodium alloy powder for the nitrogen-oxygen sensor electrode. According to the platinum-rhodium alloy powder prepared through the method, the three-phase interface uniformity of a metal catalytic functional phase and a zirconium oxide ion electrolyte substrate in electrode slurry is improved, the catalytic capacity of an electrode is improved, meanwhile, the particle size of platinum-rhodium alloy particles is properly increased, and therefore the prepared electrode slurry has better flowability, and the service life of the electrode slurry is prolonged. The problem of easy wire breakage in the subsequent sintering process is reduced, and the yield and aging life of the sensor are improved.

The pole piece comprises a pole piece body, the pole piece body comprises a dressing area and an empty foil area which are sequentially arranged along a first direction, the dressing area is provided with an active material layer, the empty foil area is provided with a diversion trench, and the diversion trench is used for circulating electrolyte. According to the application, the flow guide groove is formed in the empty foil area between the tab and the dressing area, and the flow guide groove can be used for circulating the electrolyte after the pole piece is wound, so that the diffusion rate of the electrolyte in the tab area is improved, and the manufacturing capability of liquid injection and aging procedures is improved.

According to the double-site doped ferric sodium pyrophosphate / carbon composite positive electrode material and the preparation method thereof, tungstate is introduced in the raw material mixing process, and the Fe site and the PO4 site are respectively occupied in the forms of W < 6 + > and WO4 < 2-> in the synthesis process; the chemical formula of the obtained double-site doped ferric pyrophosphate sodium / carbon composite positive electrode material is Na4Fe3-xWx (PO4) 2-y (WO4) y (P2O7) / C, x is greater than or equal to 0 and less than or equal to 0.3, and y is greater than or equal to 0 and less than or equal to 0.3. The invention also comprises a preparation method of the double-site doped ferric sodium pyrophosphate / carbon composite positive electrode material. According to the double-site doped ferric pyrophosphate sodium / carbon composite positive electrode material, the phase purity is greatly improved, non-active marmite type ferric phosphate sodium and low-capacity ferric pyrophosphate sodium impurity phases do not exist, and sodium-iron antisite defects in the structure are obviously reduced. The positive electrode material is good in electronic conductivity and ionic conductivity, high in specific capacity, good in rate capability and long in cycle life, and the high and low temperature performance is also remarkably improved.

The invention discloses a preparation method and application of a boron and fluorine co-doped potassium ion battery positive electrode material, the chemical formula of the boron and fluorine co-doped potassium ion battery positive electrode material is K < 0.5 > Mn < 0.73 > Ni < 0.22 > B < 0.05 > F < 0.05 > O < 1.95 >, bond energy of O-O and TM-O is changed through introduction of boron and fluorine, TM atom spacing is reduced, and interlayer spacing is increased, so that a wider ion transmission channel can be provided, and the service life of the battery is prolonged. And structural deformation is inhibited. In addition, introduction of boron and fluorine inhibits irreversible release of oxygen anions, and side reactions are reduced. The crystal structure of the manganese-based layered metal oxide positive electrode material is synergistically regulated by anions and cations, so that the prepared boron and fluorine co-doped potassium ion battery positive electrode material has good cycling stability and excellent rate capability.

The invention relates to the technical field of batteries, in particular to a negative pole piece, a preparation method thereof and a battery. The negative pole piece comprises a current collector; the first negative electrode coating is arranged on the surface of at least one side of the current collector in the thickness direction, the second negative electrode coating is arranged on the surface, far away from the current collector, of the first negative electrode coating, the second negative electrode coating comprises a layered multi-element metal oxide, and the layered multi-element metal oxide comprises at least two metal elements, the layered multi-element metal oxide meets at least one of the following characteristics: the capacity of the layered multi-element metal oxide is greater than or equal to 100mAh / g; the specific surface area of the layered multi-element metal oxide is greater than or equal to 100m < 2 > / g; the layered multi-element metal oxide has a porous structure; the interlayer spacing of the layered multi-element metal oxide is greater than or equal to 0.15 nm. The ion diffusion rate of the negative pole piece can be improved, rapid transmission of sodium ions on the surface of the negative pole piece is facilitated, and the cycle stability and the rapid charging performance of the battery are further improved.

The invention provides a positive electrode lithium supplementing material and a preparation method thereof, a positive electrode plate and a lithium ion battery. The positive electrode lithium supplementing material comprises an inner core and a carbon coating layer coating the surface of the inner core, the inner core comprises a titanium-doped lithium ferrite material, and carbon in the carbon coating layer is obtained by deriving and carbonizing an MOFs material. According to the positive electrode lithium supplementing material provided by the invention, through the synergistic cooperation of titanium doping and the carbon coating layer derived and carbonized by the MOFs material, the stability is good, and the lithium supplementing effect is excellent, so that the charge-discharge capacity, the rate capability and the cycling stability of a battery are improved.

The invention discloses a double-lithium compound coated silicon-carbon composite material and a preparation method thereof, the composite material has a core-shell structure, the core is passivated silicon carbon, the shell is composed of a first shell layer and a second shell layer, the first shell layer is an inorganic lithium compound, and the second shell layer is an organic lithium coating layer. The preparation method comprises the following steps: adding liquid silane and porous carbon into an organic solvent, and gasifying and decomposing under negative pressure to obtain a silicon-carbon precursor material; and then coating an inorganic lithium compound on the surface through a liquid phase method, drying, adding the obtained material, uniformly mixing with an organic lithium compound, and carrying out spray drying to obtain the lithium ion battery positive electrode material. The obtained material is applied to a lithium ion battery, can improve the cycle performance, and is high in safety and low in cost.

The invention relates to the technical field of lithium battery positive electrode materials, in particular to a neodymium-doped regenerated waste lithium iron phosphate positive electrode material and a preparation method thereof, and the positive electrode material is LiFe < 1-x > Nd < x > PO4; by doping lithium iron phosphate with a neodymium source, the lattice spacing is widened, the lithium ion transmission rate is increased, and the surfaces of doped material particles have conical flaky particle morphology; according to the method, plasma ball milling is cooperated with traditional solid phase sintering, operation is simple, the process is short, industrial application is easy, and meanwhile the regenerated positive electrode material has smaller particle size and better contact between particles. The discharge specific capacity of the obtained doped material under the condition of 1C reaches 150mAh / g, and the problem that the electrochemical performance is not ideal after neodymium is doped at present is solved to a great extent.

The invention provides a seed crystal suspension and a preparation method thereof, a preparation method of a nanoscale FER molecular sieve, and a preparation method and application of a nanoscale hydrogen type FER molecular sieve, and belongs to the field of molecular sieves. The invention provides a preparation method of a seed crystal suspension, which comprises the following steps: mixing a first silicon source, a first inorganic metal alkali source, a first aluminum source, pyrrolidine and first water to obtain first gel; performing first hydrothermal crystallization on the first gel to generate a seed crystal of which the structure is an FER molecular sieve, so as to obtain a seed crystal suspension; the temperature of the first hydrothermal crystallization is 150-180 DEG C, and the time is 10-16 hours. According to the method, pyrrolidine is selected as an organic template agent, the temperature and time of hydrothermal crystallization are adjusted, the prepared seed crystal can effectively induce the formation of crystal nucleuses when the FER molecular sieve is prepared, more initial crystal nucleuses effectively inhibit the growth of the FER molecular sieve, and the size of the FER molecular sieve is reduced.

The invention discloses a ternary positive electrode material, a preparation method thereof and an electrochemical device, and the preparation method of the ternary positive electrode material provided by the embodiment of the invention comprises the following steps: mixing a ternary positive electrode material precursor with a lithium source, and carrying out primary sintering to obtain an inner core; mixing the inner core with a lithium hydroxide solution in a spray coating manner to obtain a first mixture with a lithium hydroxide inner coating layer; mixing the first mixture with a phosphoric acid solution in a spray coating manner to obtain a second mixture with a phosphoric acid outer coating layer; the second mixture is subjected to secondary sintering, a coating layer containing lithium phosphate is formed on the surface of the inner core, the ternary positive electrode material is obtained, and the concentration gradient of lithium ions in the coating layer is gradually increased from the outside to the inside of the coating layer in the radial direction. The ternary positive electrode material prepared by adopting a step-by-step wet spraying coating mode shows excellent rate capability, cycle performance and structural stability.

The invention relates to the technical field of trimethyl boron preparation, in particular to a high-purity trimethyl boron preparation method which comprises the following steps: S1, reaction raw material preparation: magnesium powder and methane chloride react to generate methylmagnesium chloride; reacting boron trifluoride with aluminum trichloride to generate boron trichloride; s2, taking methyl magnesium chloride and boron trichloride as raw materials, and carrying out dry reaction under the conditions that the pressure is 0-1.0 MPa and the temperature is 40-150 DEG C to generate crude trimethyl boron and magnesium chloride; s3, the crude trimethyl boron is subjected to condensation, adsorption and two-stage rectification in sequence, and a high-purity trimethyl boron product is obtained; and S4, magnesium chloride is electrolyzed to obtain magnesium powder and chlorine, and the magnesium powder and the chlorine are recycled. Compared with the prior art, the method has the advantages that the trimethyl boron is prepared by adopting the dry reaction, the reaction is more sufficient, the reaction efficiency is high, the crude trimethyl boron product is purified, the product purity is improved, in addition, the byproduct magnesium chloride can be recycled, and the resource waste is reduced.

The invention discloses a silicon-carbon composite material, a preparation method thereof, a pole piece, application and an electrochemical device. The preparation method of the silicon-carbon composite material comprises the following steps: S1, carrying out graphene carbon coating and silane deposition on porous carbon to obtain a first silicon-carbon material; a carbon source system used during graphene carbon coating comprises methane, hydrogen and inert gas; s2, performing first gas-phase carbon coating and second liquid-phase carbon coating on the first silicon-carbon material to obtain a silicon-carbon composite material; and a pore-forming agent is also added when the second liquid phase is coated. The battery assembled by the silicon-carbon composite material disclosed by the invention has better electrochemical performance, and particularly has better cycle performance, first coulombic efficiency and rate capability.

The invention discloses a preparation method of a CuSb-based flow-through type gas diffusion electrode for effective electrochemical reduction of CO2, and belongs to the field of electrochemical CO2 reduction. The present invention can potentially solve the problem of insufficient mass transfer of CO2 by flow-through gas diffusion electrodes (FTGDEs). According to the method, antimony and copper (Cu) are finely regulated and controlled, and valuable products are generated through electrochemical CO2 reduction. In addition to electrochemical CO2 reduction, the CuSb flow-through gas diffusion electrodes (FTGDEs) also have significant advantages in the fields of wastewater treatment, fuel cells, metal recovery, green chemistry, battery systems, air purification and the like.