39results about How to "Alleviate chalking problems" patented technology

The invention provides a silicon-based composite material, a preparation method thereof and a lithium-ion battery. The preparation method comprises a step of mixing SiOx and a carbon source to obtaina SiOx@carbon source mixture, a step of curing and carbonizing the SiOx@carbon source mixture under an inert atmosphere to obtain SiOx@carbon, a step of dispersing the SiOx@carbon in a solution with oxidant, simultaneously adding a conductive polymer monomer and a conductive carbon material, uniformly dispersing, and polymerizing in situ to obtain the silicon-based composite material. The silicon-based composite material is a double-shell core-shell structure material, an outer shell layer is a conductive polymer layer, an inner shell layer is a carbon layer, and the conductive carbon materialis embedded into the conductive polymer monomer. The silicon-based composite material obtained by the method can effectively improve the electrochemical performance of the lithium-ion battery when the silicon-based composite material is used as a negative electrode material of the lithium-ion battery.

The invention provides a silicon-carbon composite material of a closed cage structure and a preparation method of the silicon-carbon composite material of the closed cage structure. The silicon-carboncomposite material of the closed cage structure is a hollow filled structure material in a closed cage form; the core of the hollow filled structure material is a silicon material-filled porous carbon material; the porous carbon material is filled with a silicon material; the silicon material has the void content of 50-95% in the porous carbon material; and a carbon material coats the outside ofthe silicon material-filled porous carbon material and the specific component of the carbon material is (SiOx)yC, wherein x is smaller than or equal to 2 and greater than or equal to 0 and y is smaller than or equal to 1 and greater than 0. When the silicon-carbon composite material of the closed cage structure is used as a negative electrode of a battery, contact of the silicon material and an electrolyte is isolated, the life of the battery is prolonged and the capacity performance and the cycle performance of the battery are improved.

The invention relates to a flexible negative electrode with MnO2 attached onto carbon fibers of a lithium ion battery and a preparation method of the flexible negative electrode. A metal oxide in the prior art is wrapped inside the carbon nanofibers, and thus, the contact of the metal oxide serving as an active substance with an electrode and the de-intercalation process of the metal oxide with lithium ions are not promoted; and further, the metal oxide is Fe2O3, Fe3O4, Co3O4 and the like, and such metal oxide has a defect of relatively high de-intercalation lithium potential. The preparation method is characterized by comprising the following steps of firstly, preparing a flexible carbon nanofiber net, which comprises electrostatic spinning, pre-oxidation of a polymer nanofiber net and high-temperature calcination; secondly, preparing a flexible composite fiber thin film with an MnO2 nanowire attached onto the surfaces of the carbon nanofibers, placing the flexible carbon nanofiber net in a KMnO4 solution, and completing high-temperature reaction under process conditions of a reaction temperature of 150-200 DEG C and reaction time of 30-60 minutes; and finally, cutting the flexible carbon nanofiber net into the flexible negative electrode with MnO2 attached onto the carbon fibers of the lithium ion battery.

The invention provides a composite binder, a silicon-based negative electrode plate and a preparation method thereof. The preparation method of the silicon-based negative electrode plate comprises thefollowing steps of carrying out mixing on polyvinylidene fluoride of different molecular weights through a ball mill, so as to obtain a composite binder; dissolving the composite binder in an organicsolvent to obtain a binder glue solution; dispersing a conductive agent in the binder glue solution to obtain a conductive glue solution; adding silicon-carbon composite material powder and the organic solvent into the conductive glue solution to prepare electrode slurry; coating the electrode slurry on a negative current collector, and carrying out vacuum high-temperature desolventizing treatment on the current collector coated with the electrode slurry; and carrying out roll pressing on the obtained negative electrode plate to obtain the silicon-based negative electrode plate. According tothe prepared silicon-based negative electrode plate, the performance of a lithium battery electrode material can be effectively improved, the rate performance of the battery is improved, and the cyclelife of the battery is prolonged.

The invention discloses a graphene-coated copper oxide composite cathode material and a method for manufacturing the same. The graphene-coated copper oxide composite cathode material comprises, by mass, from 20% to 90% of copper oxide and from 10% to 80% of graphene. The method includes uniformly mixing copper salt solution and graphene oxide solution at first, and stirring the copper salt solution and the graphene oxide solution at a constant temperature for 15 minutes to 1 hour to obtain mixed solution; dripping sodium hydroxide solution into the mixed solution, continuously stirring the mixed solution added with the sodium hydroxide solution for 0.5 hour to 2 hours and allowing the mixed solution added with the sodium hydroxide solution to stand for 2 to 24 hours; and performing centrifuging and hydrothermal processing for the mixed solution added with the sodium hydroxide solution to obtain a product, and drying the product at the temperature of 120 DEG C for 12 hours to obtain the graphene-coated copper oxide composite cathode material. The graphene-coated copper oxide composite cathode material and the method have the advantages that the synthesis method is simple, the manufactured graphene-coated copper oxide composite cathode material is good in performance, and technical problems of poor conductivity of a copper oxide electrode and decrease of capacity due to gradual chalking in charge and discharge processes are solved.

The invention provides a preparation method of a SiOx/carbon composite material. The method comprises steps that silica and magnesium powder are subjected to ball milling under ball milling conditions, the silica and the magnesium powder are subjected to magnesium thermal reaction, washing is then performed with hydrochloric acid till no magnesium ions are detected in the eluate, washing with thedeionized water is performed till the solution is neutral, and SiOx is obtained; the SiOx, lignin, iron source and organic solvent are mixed and sonicated to obtain SiOx/carbon precursor; the SiOx/carbon precursor is placed in a reducing atmosphere for calcination treatment, the iron source is reduced to iron, moreover, the iron plays a catalytic role in the carbonization process of lignin, the graphitization degree of the lignin is increased upon carbonization, the acid solution is utilized for several washing treatments, the iron is removed, and the SiOx/carbon composite material is obtained. The method is advantaged in that the SiOx/carbon composite material obtained by the method can improve electrochemical performance of the lithium ion battery.

The invention discloses silicon-based negative electrode slurry for lithium batteries, and a preparation method thereof. The slurry includes 40-100 parts of a silicon-based active substance, 0.1-10 parts of a conductive agent, 0.5-10 parts of a cross-linking type binder, and 20-200 parts of deionized water. The active substance in the slurry can be uniformly dispersed in a binder crosslinking network, so that the problems of pole piece pulverization and poor cycle performance caused by volume expansion of a silicon-based negative electrode material during a charging and discharging cyclic process can be effectively improved.

The invention relates to a preparation method of a yolk-shell structure molybdenum disulfide@ carbon electrode material. The preparation method includes: utilizing molybdenum disulfide precursor solvothermal ethylene glycol to obtain monodisperse molybdenum disulfide nanospheres; allowing dopamine to self-polymerize on the interfaces of molybdenum disulfide particles to obtain a molybdenum disulfide@ polydopamine core-shell structure, and performing high-temperature carbonization on molybdenum disulfide@ polydopamine to obtain core-shell structure molybdenum disulfide@ carbon nanoparticles; dispersing molybdenum disulfide@ carbon in a hydrogen peroxide solution for hydrogen peroxide etching to obtain the yolk-shell structure molybdenum disulfide@ carbon material. A gap between molybdenum disulfide and a carbon shell can be well regulated by adjusting concentration of hydrogen peroxide. When the concentration of hydrogen peroxide is 0.4vol%, discharging specific capacity of a prepared yolk-shell structure molybdenum disulfide@ carbon lithium ion battery cathode in the second circle is up to 1167mAh g-1, discharging specific capacity after being circulated for 200 circles is 880mAh g-1, capacity retaining rate is 75.4%, and rate performance is outstanding.

The invention discloses a MoSe2@EG magnesium-lithium double-salt ion battery positive electrode material and a construction method thereof. a layer of high-activity nanoflower-like two-dimensional nanomaterial MoS2 is loaded in situ on the surface of EG with good conductivity by one-step hydrothermal method, efficient saturated intercalation and de-intercalation of Li+ in the positive electrode material can be effectively promoted with the help of the high conductivity of EG and the high activity and layered structure characteristics of MoS2, and the capacity and rate characteristic of double-salt batteries are improved. In addition, MoSe2@EG can effectively alleviate a problem of material pulverization caused by volume expansion and contraction of the positive electrode material due to the intercalation and de-intercalation of Li+, thereby improving the cycle stability of the magnesium-lithium double-salt ion batteries, and prolonging the battery life.

The invention provides a conductive adhesive material and a preparation method thereof, a negative pole piece and a lithium ion battery, and relates to the field of batteries. The conductive adhesivematerial comprises polyvinyl alcohol, sodium carboxymethyl cellulose, sodium alginate, chitosan, polyethyleneimine and other polymers rich in hydroxyl groups, carboxyl groups and amino groups as raw materials, and a polymer carbon dot aqueous solution is prepared through high-temperature and high-pressure or microwave treatment. By utilizing a conductive binder material, the problems that in the prior art, when a silicon-based material is used as a negative electrode active material, the silicon-based material is poor in conductivity and is easy to fall off from a pole piece can be solved, andthe purposes of improving the conductivity of the pole piece and the binding power of the pole piece material so as to improve the energy density of the silicon negative electrode pole piece are achieved.

The invention relates to a nano silicon material with an amorphous/nanocrystalline composite structure. In the application of a lithium/sodium ion battery, after lithium/sodium is embedded into a crystalline silicon material for the first time, a composite structure of an amorphous region (silicon-lithium alloy) and a crystalline region (not embedded with lithium) is formed, and volume expansion and structural change are generated; after lithium/sodium removal, volume shrinkage causes structure collapse, i.e., silicon particle fracture and pulverization. In order to provide enough lithium/sodium embedding space in advance and inhibit the volume change of lithium/sodium embedding/removal for the first time, the invention provides an amorphous/nanocrystalline composite structure and a controllable preparation method thereof, i.e., a nano silicon material with the amorphous/nanocrystalline composite structure is prepared by adopting a spark discharge and high-energy ball milling combined process, the amorphous region surrounds the nanocrystalline, the crystal face orientation of the nanocrystalline is randomly distributed, the proportion range of the amorphous region is controllable, and the amorphous region belongs to an isotropic material. In the application of lithium and sodium ion batteries, the structure can effectively relieve the problems of material fracture and pulverization caused by silicon material expansion/shrinkage due to embedding/removal of lithium/sodium, so that the cycle performance of the silicon negative electrode is improved.

The invention relates to a preparation method of a lithium ion battery negative electrode material, and a lithium ion battery. The preparation method of the negative electrode comprises the followingsteps: adding a certain amount of Ti3AlC2 into a mixed solution of LiF and HCl, and reacting to obtain accordion-shaped Ti3C2; adding Ni salt and acrylic acid into the obtained Ti3C2 turbid liquid, and carrying out irradiation in gamma rays generated by <60>Co; and pouring the turbid liquid into liquid nitrogen for quick freezing, then freeze-drying the obtained product, and finally coating the Ti3C2-NiO with a carbon layer by adopting a CVD method. According to the invention, the prepared composite material NiO particles are uniformly dispersed among three-dimensional accordion-shaped Ti3C2 sheet-shaped gaps, so that material pulverization and structure collapse caused by the volume expansion effect of NiO in the charging and discharging process are effectively relieved, and the conductivity of NiO is effectively improved through the Ti3C2 and CVD carbon layer.

The invention discloses a preparation method of nanorod-like vanadium tetrasulfide powder. The method comprises the following steps: (1) dissolving thioacetamide in absolute ethyl alcohol, and stirring until whole dissolution is completed to obtain a mixture A; (2) adding ammonium vanadate to the mixture A, and stirring until whole dissolution is completed to obtain a mixture B; (3) dripping dilute hydrochloric acid into the mixture B under stirring conditions to form a transparent solution to obtain a mixture C; (4) transferring the mixture C to a hydrothermal reaction kettle, and carrying out a hydrothermal reaction for 24 to 25 hours; (5) after the reaction is finished, naturally cooling, performing centrifugal washing several times, and then performing vacuum drying to obtain the nanorod-like vanadium tetrasulfide powder. The nanorod-like vanadium tetrasulfide prepared by the method is higher in specific capacity, excellent in cycle stability, long in service life and higher in electrical conductivity.

The invention provides a copper foil composite material, a preparation method thereof, a negative pole piece and a lithium ion battery, and relates to the field of batteries. The copper foil composite material comprises a copper foil, and the surface of the copper foil is modified by an amino silane coupling agent. By utilizing the copper foil composite material, the problems that in the prior art, when a silicon-based material is used as a negative electrode active material, the capacity of the silicon-based material is rapidly attenuated in the early cycle and foil leakage occurs in the later cycle can be solved.