77results about How to "High lithium ion transfer number" patented technology

The invention relates to a method for preparing a polyvinylidene fluoride (PVDF) porous nanofiber membrane with a high ion migration number. The method is characterized by comprising the following steps of: 1, adding a single-walled carbon nanotube and lithium salts into an organic solvent to form a mixed solution; adding polyvinylidene fluoride, heating, stirring and dissolving, cooling to the room temperature, adding polyvinyl pyrrolidone, stirring and dissolving to obtain a spinning solution; and 2, performing electrostatic spinning on the obtained spinning solution to obtain a fiber membrane; impregnating the obtained fiber membrane in ethanol for 1-2 hours to obtain the PVDF porous nanofiber membrane with the high ion migration number. The PVDF porous nanofiber membrane prepared with the method is used as a lithium ion battery isolation membrane, and maintains good mechanical strength at the same time of maintaining high lithium ion migration number, high liquid absorption rate and good electrochemical stability in a range of from 20 to 70 DEG C.

The invention provides electrolyte solution, which contains an organic solvent, a lithium salt or lithium oxide, a compound containing an electron-withdrawing group and an additive, wherein the solvent is a carbonic ester and/or ether solvent; and the additive is a compound having a molecular formula of RBC2O4Li, R in the formula may be -C2O4, -F2, -C6H2O2, alkyl or fluorine-containing substitutedalkyl, and the concentration of the additive in the electrolyte solution is 0.005 to 0.1mol/l. The invention also provides a preparation method of the electrolyte solution. The invention also provides a lithium cell, which comprises a lithium cell diaphragm soaked in the electrolyte solution. The electrolyte solution of the invention has the advantages of high transport number of lithium ions, high conductivity and wide electrochemical window. Meanwhile, the electrolyte solution has high compatibility with a carbon cathode material.

The invention provides an electrolyte. The electrolyte comprises a solvent and lithium salt, and the concentration of the lithium salt is 3.1-5.0 mol/L. When the high-concentration electrolyte is used, a complexation state of lithium ions and a solvent is changed from complexation of 3-4 solvent molecules by each lithium ion to complexation of 1-2 solvent molecules by one lithium ion, complexationforce of the lithium ions and the solvent molecules are strong, the energy barrier for solvent reduction is increased, and work voltage is risen. The above high-concentration electrolyte is partiallyreduced on a surface of a cathode, a layer of SEI is formed which is better than that formed through reduction of current electrolytes, so that further decomposition of the electrolyte can be inhibited, thin thickness and good toughness can be kept during a cycle process, accordingly, interface impedance and lithium ion transport number cannot be increased with increase of cycle number, and highcoulombic efficiency and specific capacity can be kept at a battery cycle late period.

The invention belongs to the related field of polymer electrolyte systems. The invention discloses a single-ion polymer electrolyte system as well as a preparation method and application thereof. Thesingle-ion polymer electrolyte system is composed of a single-ion polymer electrolyte and a metal salt, wherein the single-ion polymer electrolyte is obtained by carrying out reversible addition-fragmentation chain transfer polymerization reaction on three monomers including a single-ion conductor lithium salt containing a p-styrenesulfonyl group, UPyMA containing quadruple hydrogen bonds and methoxypolyethylene glycol methacrylate. According to the invention, the key structure and related composition in the single-ion polymer electrolyte system, the overall process flow of the preparation method and other aspects are optimally designed; and, compared with the prior art, the invention is advantageous in that not only can the phenomenon that a polymer electrolyte system is easy to crack bebetter solved, but also the metal ion transference number and the ionic conductivity can be remarkably improved, and meanwhile, the growth of metal dendrites is effectively inhibited, so that the polymer electrolyte is particularly suitable for the field of metal ion batteries such as lithium ion batteries.

A solid polymer electrolyte for a battery is disclosed. The solid polymer electrolyte includes a polymer capable of solvating a lithium salt, a lithium salt, and nanocellulose in the form of nanofibers or nanocrystals onto which are grafted anions of lithium salt, the nanofibers or nanocrystals cellulose providing increased mechanical strength to the solid polymer electrolyte to resist growth of dendrites on the surface of the metallic lithium anode.

The invention belongs to the technical field of polymer synthesis and discloses a polyp-styrene sulfonyl(trifluoromethyl sulfonyl)lithium imide-polyvinylidene carbonate copolymer and application thereof. The copolymer is synthesized by the following steps: adding a p-styrene sulfonyl(trifluoromethyl sulfonyl)lithium imide monomer, a vinylidene carbonate monomer and a catalyst into a solvent I andperforming polymerization reaction at 70 to 100 DEG C, wherein the p-styrene sulfonyl(trifluoromethyl sulfonyl)lithium imide monomer is prepared by the steps of performing reaction on sodium p-styrenesulfonate and sulfoxide chloride in a solvent at -10 to 25 DEG C, adding an acid-binding agent, an activating agent and trifluoromethyl sulfonamide and performing reaction at -10 to 25 DEG C; addingpotassium carbonate and performing reaction at 25 to 70 DEG C; and adding lithium perchlorate and performing reaction at 25 to 60 DEG C. The copolymer provided by the invention has high lithium ion migration number and room-temperature conductivity, is simple in preparation method, can realize large-scale production and can serve as lithium ion battery electrolyte.

The invention discloses a preparation method of single-ionic conductor SiO2@Li<+1> with a core-shell structure in a polymer electrolyte. The preparation method is characterized in that the single-ionic conductor SiO2@Li<+1> with the core-shell structure is prepared by a hydrolysis-free radical polymerization-ion exchange method. The preparation method comprises the steps of: preparing mono-dispersed sphere-shaped functional type SiO2 by a silicon source and aqueous ethanol solution in the presence of a catalyst by controlling hydrolysis temperature; adding organic sodium salt in the presence of a free radical initiator to prepare SiO2@Na<+1> through free radical polymerization; and finally, performing ion exchange on SiO2@Na<+1> and lithium salt to prepare the single-ionic conductor SiO2@Li<+1> with the core-shell structure. According to the invention, the composite polymer electrolyte doped with the prepared single-ionic conductor SiO2@Li<+1> with the core-shell structure has high lithium-ion transference number and good multiplying power and cycle performance.

The invention provides a modified separator, a preparation method thereof and a lithium ion battery. The modified separator comprises a separator substrate and a polymer coating layer, wherein the polymer coating layer is arranged on a surface of the separator substrate and comprises a polymer, and a side link of the polymer is substituted by lithium sulfonate. The surface of the separator substrate in the modified separator comprises the polymer coating layer, the polymer coating layer comprises the lithium sulfonate group, the modified separator has a function of conducting lithium ions, themobility number of the lithium ions in an electrolyte can be increased when the modified separator is used in the lithium ion battery, the AC resistance value of the modified separator is reduced, the concentration polarization phenomenon is reduced, so that the growth of lithium dendrites of a battery negative electrode is reduced or prevented, the short-circuit risk of the battery is reduced, the safety and the rate performance of the lithium ion battery are effectively improved, and the cycle service lifetime of the lithium ion battery is prolonged. According to the preparation method of the modified separator, the polymer coating layer of which the side link is substituted by the lithium sulfonate is coated on the surface of the separator substrate, so that the modified separator hasrelatively low substitution degree in a polymer and also has relatively high lithium ion mobility, and the effect of reducing the lithium dendrites is achieved.

The invention relates to the field of materials and belongs to the technical field of preparation of an electrolyte material of a lithium ion battery. The electrolyte is composed of polyoxyethylene (PEO), high molecular weight polyacrylamide (PAM), acrylamide and ethylene glycol monomethyl ether acrylate copolymer (P(AM-co-PEGMA)), lithium salt and nanometer filler. According to the invention, high molecular weight PAM containing a polar group and having an excellent support function is used as a support phase, PEO is used as a transfer phase, P(AM-co-PEGMA) is used as PAM and PEO solubilizers, and the nanometer filler is used as an enhancer and a PEO crystallization inhibitor, so that the electrolyte, with high lithium ion transport number, high ionic conductivity, small interface resistance and good size stability, can be prepared and applied to the lithium ion battery. According to the preparation method provided by the invention, no organic solvent is added; the preparation method belongs to a clean preparation technique; evaporation solvents are prevented from polluting the environment; the resource waste is avoided; the operation is simple and convenient; the preparation cost is low; and the efficiency is high.

The invention discloses a high-conductivity coating diaphragm for a lithium-sulfur battery as well as a preparation method and application of the high-conductivity coating diaphragm. The preparation method comprises the following steps: immersing a polyolefin film into the first slurry; coating the positive electrode side of the polyolefin film with second slurry so as to obtain the high-conductivity coating diaphragm for the lithium-sulfur battery; wherein the preparation method of the first slurry comprises the following steps: uniformly dispersing a polymer in deionized water to obtain thefirst slurry, and the preparation method of the second slurry comprises the following steps: adding a dispersing agent into a solvent, uniformly stirring to obtain a mixed solution, uniformly mixing tannic acid and a carbon conductor, adding the mixture into the mixed solution, uniformly stirring, and sanding to obtain the second slurry. By introducing the functional layer to the surface of the polyolefin diaphragm, on one hand, generation of polysulfide is prevented, and the shuttle effect is avoided; on the other hand, the introduction of the functional layer can improve the polarity of thesurface of the diaphragm, so that the electrolyte wettability of the diaphragm is improved, uniform transmission of lithium ions in the diaphragm is facilitated, and the ionic conductivity and the lithium ion transference number of the battery are improved.

The invention discloses a composite solid electrolyte film based on NASICON type electrolyte and a preparation method thereof. The invention belongs to the field of all-solid-state lithium batteries.The objective of the invention is to solve technical problems of poor compatibility between a rigid inorganic solid electrolyte and an electrode interface, too low ionic conductivity of a polymer-based solid electrolyte, and large room-temperature polarization and operation at a high temperature of an LATP-based all-solid-state lithium battery with a polymer interface layer in the prior art. The product is prepared from NASICON type solid electrolyte powder, a polymer and a lithium salt through a solution casting method. The method comprises the following steps: 1, adding solid electrolyte powder, a polymer and a lithium salt into a solvent, and performing stirring to form a uniform slurry; 2, coating a glass plate substrate with the slurry, and performing drying to obtain a composite solid electrolyte film; and 3, infiltrating the composite solid electrolyte film in an electrolyte, sucking the electrolyte on the surface of the electrolyte film, and performing vacuum drying to obtain the composite solid electrolyte.

For overcoming the problems in the prior art that a polymer electrolyte is intolerant to high temperature, low in mechanical strength and low in ionic conductivity, the invention provides a polymer electrolyte preparing method including the steps: S1, mixing a monomer and a polymer lithium salt in water, to obtain a pre-emulsified emulsion; S2, heating the pre-emulsified emulsion up to 65-75 DEG C, and carrying out a reaction for 0.5-1 h; S3, again taking the monomer and the polymer lithium salt, and mixing in water, to obtain a second emulsion; and adding the second emulsion to the pre-emulsified emulsion for multiple times, and carrying out a reaction for 4-6 h; S4, heating up to 80-90 DEG C, and carrying out a reaction for 0.5-1 h, to obtain a polymer emulsion; and S5, infiltrating a non-woven substrate in the polymer emulsion, carrying out ultrasonic treatment for 10-60 s, and drying. At the same time, the invention also discloses the polymer electrolyte prepared by the method. The polymer electrolyte provided by the invention is resistant to high temperature, high in mechanical strength, high in ionic conductivity and high in lithium ion transference number.

The invention discloses a high-rate electrolyte of a lithium ion battery. According to the electrolyte provided by the invention, a mixed lithium salt composed of lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide is used in the electrolyte, so that the conductivity of the electrolyte can be improved, the transference number of lithium ions can be increased, a passivation film with low impedance is formed, therefore, the rate of the electrolyte is increased; meanwhile, a flame retardant additive is added into the electrolyte, so that the flame retardancy of the electrolyte can befurther improved, and the safety of the electrolyte is indirectly improved.

The invention discloses high-conductivity slurry for lithium-sulfur batteries, a diaphragm based on the high-conductivity slurry and an application. The preparation method of the high-conductivity slurry for lithium-sulfur batteries comprises the following steps: mixing water with ethanol, adding a dispersing agent, and stirring the substances well to obtain a first mixed solution; and mixing thefirst mixed solution with a second mixed solution, stirring the first mixed solution and the second mixed solution well and putting the first mixed solution and the second mixed solution in a sand mill for sand milling for 30-90min to obtain high-conductivity slurry for lithium-sulfur batteries, the second mixed solution being a mixture of an ammonia lithium-conducting polymer, tannic acid, a carbon conductor and a pore-forming additive. By introducing a functional layer to the surface of a polyolefin diaphragm, the generation of polysulfide is prevented, and the shuttle effect is avoided. Onthe other hand, the introduction of the functional layer can improve the polarity of the surface of the diaphragm so as to improve the electrolyte wettability of the diaphragm, and can promote the migration of lithium ions, improve the ionic conductivity of the diaphragm and the number of lithium ions migrated and finally improve the cycle performance and rate performance of batteries.

The invention discloses a preparation method of an oxygen vacancy lithium titanate composite material. The method comprises the steps of putting pure lithium titanate or metal element M-doped lithium titanate into a mixed gas of an organic gas and an inert gas, carrying out heat preservation at 700-1,000 DEG C for 5min to 24h, and cooling to obtain the oxygen vacancy lithium titanate composite material, wherein the metal element M is selected from at least one of iron, cobalt, nickel, molybdenum, zirconium, copper, zinc, magnesium, aluminum, silicon and rare earth element; the organic gas is at least one of alkane, olefin, alkyne or gaseous alcohol with seven or less carbon atoms; and the volume of the organic gas accounts for 5%-95% of the total volume of the mixed gas. The invention further discloses the oxygen vacancy lithium titanate composite material prepared by the method, and a lithium titanate battery adopting the oxygen vacancy lithium titanate composite material.

The invention discloses a high-conductivity polymer solid electrolyte and a preparation method thereof. The preparation method comprises the following steps: adding PEO powder into a solution containing lithium salt, then adding perovskite quantum dots, heating and stirring at 50-70 DEG C for 20-28 hours to obtain uniform slurry, putting the slurry into a mold to form a membrane, removing a solvent, and finally performing vacuum drying to prepare a high-conductivity polymer solid electrolyte membrane. A PEO-based polymer solid electrolyte is mainly modified, the room-temperature ionic conductivity, the lithium ion transference number and the compatibility to a lithium metal negative electrode can be greatly improved through the modified polymer solid electrolyte, and finally the PEO-based polymer solid electrolyte with the high conductivity characteristic is obtained.

The invention discloses a composite gel polymer electrolyte applying polymer nanofiller, a preparation method and a solid-state lithium battery using the electrolyte. The composite gel polymer electrolyte comprises a polyurethane polymer, a polyquinone nanosheet filler and a lithium electrolyte salt. The polymer nanofiller provided by the invention has lithium affinity, so that the composite gel polymer electrolyte not only has flexibility, high room-temperature ionic conductance and good electrochemical and interface stability, but also can significantly inhibit the formation of lithium dendrites. When the electrolyte is used as the electrolyte of the lithium battery, the problems of liquid leakage and solvent volatilization of the traditional liquid electrolyte can be solved, and the lithium dendrites can be prevented from piercing the diaphragm to cause internal short circuit.

The invention relates to a preparation technology of lithium ion battery electrolytes, and aims to provide a preparation and application method of a composite single-ion solid electrolyte. The methodcomprises the steps of: taking p-styryl fluoro alkyl sulfimide lithium, acrylate polyether, nitrile imidazole type ionic liquid and a silane coupling agent KH-570, and performing free radical polymerization under the stirring condition and the initiation of ultraviolet light to prepare a copolymer; uniformly dispersing the copolymer and an inorganic nano material in a solvent to prepare a castingsolution; pouring the casting solution on a clean membrane-making glass mould uniformly, and transferring the membrane-making glass mould to a vacuum drying oven; and performing heating to completelyvolatilize the solvent, dehydrating, condensing and crosslinking the polymer to obtain a membranous composite single-ion solid electrolyte. The composite single-ion solid electrolyte obtained by the invention has the higher ionic conductivity and lithium ion transference number and good thermal stability and electrochemical stability, and has the excellent long-cycle performance and high-voltage resistance when used in a lithium ion battery; and moreover, the preparation method is simple and mild in condition and is capable of achieving large-scale production.