755results about How to "Small volume change" patented technology

The present invention discloses a preparation method of a complex lithium negative pole of a solid state battery, and belongs to the technical field of electrochemistry and new energy resources. The preparation method mainly comprises the steps: depositing lithium metal on three-dimensional carbon material or foam porous material gaps by using a heat infusing melting method or an electrodeposition method to obtain the complex lithium negative pole, wherein the application of a three-dimensional framework plays two roles, namely, providing adequate space for pre-storing lithium in the preparation process; providing a carrier for receiving metal lithium in a battery circulation process. The complex lithium negative pole can be widely applied in lithium metal batteries such as lithium ion batteries, lithium-air batteries, lithium-sulfur batteries, and solid state batteries. In the assembled symmetric solid state battery, under large electric current density of 5mA cm-2, a stable voltage decay (200mV) can still be kept after circulation for 100 times, in the battery circulation, the growth of lithium dendrites can be inhibited and the pole volume change can be stabilized, and the advantages of being good in circulation stability, and long service life can be realized; in the present invention, a carrier material is rich, and low in price; the process is controlled, the cost is low, and the batch production can be realized.

A silicon composite comprises silicon particles whose surface is at least partially coated with a silicon carbide layer. It is prepared by subjecting a silicon powder to thermal CVD with an organic hydrocarbon gas and/or vapor at 900-1,400° C., and heating the powder for removing an excess free carbon layer from the surface through oxidative decomposition.

The invention provides a lithium ion battery cathode material and a preparation method of the lithium ion battery cathode material as well as a lithium ion battery. The lithium ion battery cathode material comprises an inner core, a middle layer outside the inner core and an outer shell wrapping the middle layer, the inner core is Si-C particles, the middle layer is a foam layer, the outer shell is an amorphous carbon layer and the Si-C particles are formed by Si particles and C materials. Compared with the prior art, a middle carbon foam layer existing between the Si-C particle inner core and the amorphous carbon outer shell can form an conductive network structure, thus improving conductivity of a material and buffering enormous volume change of Si particles in the charge-discharge processes; and the amorphous carbon outer shell layer can maintain the core-shell structure of the cathode material, and the cladding layer of the core-shell structure can buffer the volume change, improve cycling stability of electrodes, reduce contact between active substances and an electrolyte, improve first coulombic efficiency of an electrode, prevent nanoparticle aggregation and enhance electrode conductivity.

A negative electrode for a rechargeable lithium battery and a rechargeable lithium battery including the same are provided. The negative electrode for a rechargeable lithium battery includes a current collector, and a negative active material layer on the current collector. The negative active material layer includes an interpenetrating network, and a negative active material in the interpenetrating network. The interpenetrating network is formed by cross-linking a first polymer having a hydroxyl or amine group and a second polymer having a carboxylic acid group. The negative electrode for a rechargeable lithium battery minimizes volume expansion and imparts good cycle-life characteristics and initial formation efficiency.

The invention discloses a spherical silicon-oxygen-carbon negative electrode composite material, which is of a three-layer structure comprising an inner layer, an intermediate layer and an outer layer, wherein the inner layer is an SiOx/graphite substrate; the intermediate layer is an amorphous carbon coating layer; the outer layer is a carbon nanotube coating layer; the mass of the inner layer SiOx/graphite substrate accounts for 80%-90% of total mass of the spherical silicon-oxygen-carbon negative electrode composite material; the mass of the intermediate layer amorphous carbon accounts for 5%-10% of total mass of the spherical silicon-oxygen-carbon negative electrode composite material; and the outer layer carbon nanotube accounts for 5%-10% of total mass of the spherical silicon-oxygen-carbon negative electrode composite material. The grain diameter of the adopted SiOx substrate is smaller than 5 microns; the grain diameter is relatively small; intercalation and deintercalation of active substances are facilitated; higher specific capacity can be obtained; meanwhile, a dispersing agent is added when an SiOx sample is ground; and condition that the SiOx with a relatively small grain diameter is agglomerated in quantity to affect the performance is prevented.

The invention provides a lithium ion battery cathode material, comprising graphene, nanometer silicon particles distributed in a graphene lamellar structure, and net-shaped carbon materials distributed between the graphene lamellar structure and the nanometer silicon particles. According to the invention, the graphene has a good lamellar structure, nanometer silicon particles are distributed in the graphene lamellar structure, and net-shaped carbon materials are distributed between the graphene lamellar layer and the nanometer silicon particles. According to the lithium ion battery cathode material provided by the invention, carbon materials between the graphene lamellar layer and the network structure are in tight contact with the nanometer silicon particles, thereby improving conductivity of the cathode material, and at the same time, effectively buffering enormous volume change of silicon particles, thus the lithium ion battery cathode material has good cycle performance.

The invention relates to a lithium ion battery composite cathode material and a preparation method thereof, which belongs to the technical field of lithium ion battery. The invention aims at improving the cycle performance of silicon cathode material at the same time when keeping the high ratio volume of lithium ion battery silicon cathode material. The proposal of the invention is that silica-based material coated by disordered carbon is treated with surface modification processing by utilizing lithium salt, namely, the lithium salt is coated on the surface of Si/G/DC (silicon/graphite/disordered carbon) to be prepared into the composite cathode material, therefore, the lithium-embedding and removing depth of the silicon can be effectively controlled, and the material is the lithium ion battery composite cathode material which has high specific capacity and good cyclical stability; furthermore, the material is safe and pollution-free, and presents higher thermal stability in various lithium salt electrolytes and solvents.

The invention relates to the field of lithium ion battery electrode materials, in particular to a graphene-coated silicon nanoparticle with a novel structure, and a preparation method thereof. The graphene-coated silicon nanoparticle is characterized by being formed by a reduced graphene oxide/carbon shell coating an outer layer, a silicon nanoparticle core located in the reduced graphene oxide/carbon shell, and a cavity layer between the reduced graphene oxide/carbon shell and the silicon nanoparticle core. Compared with the prior art, according to the graphene-coated silicon nanoparticle provided by the invention, the thickness of a surface oxidation layer of a silicon particle is easy to control; surface oxidation silicon powder is dispersed in a solvent easily, and hydroxy on the surface of the particle enables the particle to be combined with a modifier easily; graphene coating the particle surface helps increase electric contact between particles as well as between the particle and a current collector, and is beneficial for electron transfer in a composite material to reduce impedance; carbon produced through high-temperature pyrolyzing of a modifier carbon chain and graphene jointly form a shell with a certain strength, and a stable SEI can be formed favorably.

The invention discloses a polymer composite solid electrolyte and a preparation method and application thereof. The polymer composite solid electrolyte is prepared from polyphenylene sulfide, a lithium salt and an organic quinones electron acceptor and is taken as a polymer composite solid electrolyte of a lithium-sulfur battery, the polymer composite solid electrolyte, carbon black and elemental sulfur are fabricated to a composite sulfur electrode material, and thus, a novel lithium-sulfur battery system is formed. The high-molecular polymer composite solid electrolyte provides a relatively good lithium ion migration passage, the lithium ion conductivity of a composite positive electrode material is improved, the high-molecular polymer composite solid electrolyte has certain rigidity and toughness, the volume change of a positive electrode after charge and discharge of the lithium-sulfur battery is buffered, the discharge specific capacity of the lithium-sulfur battery is improved, and the cycle lifetime of the lithium-sulfur battery is prolonged.

The invention discloses an asphalt pavement repair material, and belongs to the field of engineering materials. The asphalt pavement repair material is prepared from 20-60 parts of monomers of thermosetting polymers and/or prepolymers of the thermosetting polymers, 2-8 parts of an antioxidant, 1-8 parts of an accelerant, 10-30 parts of an admixture, 5-60 parts of the thermosetting polymers, 10-40parts of an initiator, 10-20 parts of a reinforcing agent, 1-60 parts of a diluent and 10-40 parts of aggregates. The asphalt pavement repair material has the advantages of being high in condensationrate, strength, waterproofness and abrasion performance and capable of repairing pavement and getting the traffic to move again in 30 minutes and making construction easy. According to a pavement repaired with the asphalt pavement repair material, the compressive strength can reach 100 MPa, the wet wheel abrasion value is smaller than 800 g*m<-2>, and the load wheel adhesion sand amount water immersion 1d is smaller than 450 g*m<-2>.

The invention belongs to the technical field of material and energy and particularly relates to three-dimensional porous carbon-coated zinc selenide material for lithium ion battery anodes and a preparation method of the material. The preparation method comprises the specific steps of sintering zinc-based zeolite imidazate metal organic framework material (ZIF-8) as a precursor or template with selenium powder under the protection of an inert atmosphere at high temperature for a certain time, and carrying out synchronous selenization and carbonization to finally prepare the carbon-coated zinc selenide composite material. The composite material prepared herein and the preparation method thereof provide effective composition of zinc selenide and graphite carbon, the component ingredients generate great interfacial coupling effect, volume expansion effect of the zinc selenide material during charging and discharging can be effectively relieved and inhibited, the conductivity of the material is improved, and accordingly the composite material has very high specific capacity and excellent cycle stability and rate performance when applied as lithium ion battery anode material. The preparation process is simple, the preparation conditions are mild, and the cost is low.

The invention discloses a three-dimensional self-supported lithium-loving carrier-packaged metal lithium composite negative electrode and a preparation method thereof. The three-dimensional self-supported lithium-loving carrier-packaged metal lithium composite negative electrode comprises the following steps of 1) carbonizing melamine foam in an inertia atmosphere to obtain a nitrogen-rich lithium-loving three-dimensional self-supported carrier; and 2) packaging metal lithium in holes of the three-dimensional self-supported carrier to obtain the metal lithium composite negative electrode. Carbon sponge obtained by carbonization of melamine foam is used as a metal lithium carrier, and the metal lithium composite negative electrode has effects of guiding metal lithium to be uniformly deposited and preventing dendrite from being generated. Lithium-loving functional groups are uniformly arranged on the carrier, a lithium-loving coating layer is deposited on a hole surface of the carrier, the lithium-loving performance of the carrier is improved, the volume change of the metal lithium electrode during the circulation process is effectively buffered, moreover, the lithium-loving functional groups uniformly arranged on the three-dimensional carrier are used as active sites for metal lithium deposition, the nucleation over-potential is reduced, uniform nucleation of metal lithium can be effectively controlled, so that the dendrite generation is prevented.

The invention discloses a negative pole made of a silicon/graphite nanosheet composite material of a lithium ion battery, which comprises the following components in percentage by mass: 85 to 95 percent of nanometer silicon powder-graphite nanosheet composite material, and 5 to 15 percent of polyvinylidene fluoride, wherein the content of nanometer silicon powder is between 20 and 75 percent in the nanometer silicon powder-graphite nanosheet composite material. A preparation method thereof comprises the steps of: preparing graphite oxide, preparing a mixed dispersion system of the nanometer silicon powder and graphite oxide nanosheets; adding a reducing agent, namely hydrazine hydrate into the mixed dispersion system of the nanometer silicon powder and the graphite oxide nanosheets, and reducing the graphite oxide nanosheets into graphite nanosheets to obtain a composite material of the nanometer silicon powder and the graphite nanosheets; and fully mixing the composite material of the nanometer silicon powder and the graphite nanosheets with N-methylpyrrolidone sol of the polyvinylidene fluoride, blending the mixture into paste, evenly coating the paste onto a copper coil, and performing drying and roller compaction. The negative pole made of the silicon/graphite nanosheet composite material of the lithium ion battery has high electrochemical capacity and good cycling stability performance.

The invention relates to a preparation method of core-shell TiO2/ZnO photocatalyst and the application thereof, which relates to the preparation method of a photocatalyst and the application thereof. The invention solves the problem that the valence band electron of the existing photocatalyst can transit onto a conduction band only under the excitation of ultraviolet radiation. The preparation method of the invention is that: 1. Zn(CH3/COO)2/2H2/O is mixed into a Polyvinyl alcohol solution and heated in step after being dried and then cooled down to room temperature; 2. tetrabutyl titanate, absolute ethyl alcohol and triethanolamine are mixed together and aged, then the product of the step 1 is added into the solution for dissolving following by drying and heat treatment. The core-shell TiO2/ZnO photocatalyst prepared by the invention is painted on cross linked ethylene, layered perovskite, molten salt crystal water and salt or Al-Si material as thermal energy storage material. The electron of the TiO2 in the invention can transit onto the conduction band under common lighting condition, which leads photo electron to be effectively separated.

The invention discloses a lithium-sulfur battery positive-pole composite material with an imitated cellular structure and a preparation method thereof. In the positive-pole composite material, a conductive polymer film layer and nanometer oxide inlaid inside the conductive polymer film layer form a cell membrane, an elemental sulfur particle serves as a cell nucleus, and the three portions jointly form the imitated cellular structure. The composite material is prepared by conducting ultrasonic dispersion on the elemental sulfur particle and the nanometer oxide in water in the presence of a surface active agent, adding a conductive polymer monomer and an acid solution, performing even stirring and then adding an oxidizing agent to perform stirring reaction. The preparation method is simple in process, low in cost, low in energy consumption, controllable in sulfur content and good in repeatability and enables large-scale production to be easily achieved. The composite material is made into a lithium-sulfur battery positive pole, loss of active substances in the charging-discharging process can be effectively inhibited, improvement of the specific discharge capacity of a battery material and the utilization ratio of the active substances is facilitated, and accordingly the battery cycle performance is greatly improved.

The invention discloses a method for preparing a composite sodium negative electrode for a sodium-ion battery and belongs to the field of new energy materials. According to the method disclosed by the invention, metal sodium is deposited in gaps of a three-dimensional carbon material or a foamed porous material and other carriers through a hot infusion melting method or an electrodeposition method, so that the composite sodium negative electrode is prepared, wherein the three-dimensional carbon material is applied to providing a sufficient space for pre-stored sodium in the preparation process and providing a carrier for receiving the metal sodium in the battery cycle process. The composite sodium negative electrode can be widely applied to the sodium-ion battery, a sodium air battery, a sodium-sulfur cell and other sodium metal batteries, is assembled into a sodium-ion symmetric cell to still keep a stable voltage platform under high current density, is capable of inhibiting sodium dendritic growth and stabilizing volume change of the sodium electrode in the battery cycle process, and has the advantages of good cycling stability, long service life and the like. The method disclosed by the invention is rich and cheap in carrier materials, controllable in preparation process, low in production cost and capable of realizing batch production.

A fuel system for use in a combustion chamber of a compression ignition internal combustion engine comprises a pump arrangement having a pump chamber for fluid and a piston which is movable outwardly from the combustion chamber in response to pressure generated within the combustion chamber as a result of combustion so as to pressurise fluid within the pump chamber. The system also includes a control valve assembly for controlling the supply of fluid that is pressurised within the pump chamber to an accumulator volume. In one particular aspect, the invention provides a fuel system for use in an engine having at least two engine cylinders, comprising a first pump arrangement associated with one of the engine cylinders and a second pump arrangement associated with the other of the engine cylinders, each of the first and second pump arrangements having a pump chamber for fluid and a piston which is movable outwardly from the combustion chamber in response to pressure generated within the combustion chamber as a result of combustion so as to pressurise fuel within the pump chamber. At least one control valve assembly controls the supply of fluid that is pressurised within the pump chamber of at least one of the pump arrangements to an accumulator volume.

The invention discloses a method for preparing a linear polyurethane phase change material. The method comprises the following steps: dissolving polyethylene glycol and diisocyanate into solvent in inert atmosphere, reacting in the presence of optional catalyst, adding tertiary amine type chain extender containing hydroxyl for chain extension, adding an optional neutralizer for salt formation so as to obtain the linear polyurethane phase change material, wherein the molar ratio of the sum of hydroxyl of polyethylene glycol and hydroxyl of chain extender to the isocyanate group of diisocyanate is 1:1, the add amount of the catalyst accounts for 0-1% the total weight of the polyethylene glycol, diisocyanate and chain extender, the molar ratio of neutralizer to tertiary amine type chain extender is 0-1, and the molecular weight of the polyethylene glycol is higher than 2000. The linear polyurethane phase change material prepared by the method has a linear structure and large enthalpy of phase change, has a simple preparation method, is low in cost, has stable property, can be stored for long time, is not solidified and cross-linked, is easy to process and shape, and is beneficial to large-scale popularization and application.