551 results about "Interface impedance" patented technology

The invention relates to organic-inorganic all-solid-state composite electrolyte as well as preparation and application methods thereof, belonging to the field of lithium ion batteries. According to the organic-inorganic all-solid-state composite electrolyte, a highly-ordered three-dimensional connection network skeleton is formed by an inorganic fast lithium ion conductor, and a three-dimensional connection network is filled with a polymer and lithium salt. The organic-inorganic all-solid-state composite electrolyte which is flexible and has a controllable three-dimensional connection network structure is prepared. The electrolyte is high in lithium ion conductivity, wide in electrochemical window, good in mechanical property and stable to lithium metal. A lithium ion secondary battery assembled by a composite electrolyte membrane prepared by the method is high in capacity, stable in cycle performance, low in interface impedance and good in interface stability.

The invention provides a polymer porous membrane, a preparation method of the polymer porous membrane, a polymer electrolyte, a polymer battery and a preparation method of the polymer battery. A carbon material is dispersed in the polymer porous membrane, so that the degree of crystallization of a polymer which constitutes the polymer porous membrane is lowered and the liquid absorption of the polymer porous membrane is increased; the liquid absorption rate, liquid holding capability and ionic conductivity of the polymer porous membrane are increased; interface impedance is reduced, battery magnification discharging performance and the circulating performance of the battery are enhanced; simultaneously, the battery prepared by the method has excellent high temperature circulation and storage performance and low expansion ratio at a high temperature and further meets the development requirement of the polymer battery. Simultaneously, the preparation method is simple and is easy to implement and the prepared battery has high performance.

The invention discloses a preparation method of an improved room temperature electron ion fast transfer electrode slicefor a solid-state secondary lithium battery. The method comprises the following steps: (1) evenly mixing an active material, a conductive agent and a fast ion conductor according to a certain proportion; (2) adding a certain amount of a binder into the mixture, and mixing uniformly to obtain a uniform slurry; and (3) preparing the slurry into slices, and drying to obtain the required electrode slice. The preparation method of the electrode slice preparation uses the fast ion conductor material with high temperature high lithium ion conductivity; the material can play the role of increasing the contact area between the active particles and solid electrolyte, and he form a three-dimensional electron and lithium ion transport network, so as to ensure the rapid conduction of the electrons in the electrode also improve the transmission rate of lithium ions between the active particles and electrolyte. Therefore, the preparation method is beneficial to reducing the interface impedance among the active particles in the electrode slice and between the active particles and the solid electrolyte, thereby increasing the power rate performance of the solid-state secondary lithium battery.

The invention relates to a high-power flexible packaged lithium ion battery and a processing process thereof. An individual battery cell comprises a negative plate, a positive plate, a first membrane and a second membrane, wherein the first membrane, the negative plate, the second membrane and the positive plate are stacked in sequence; the positive plate is arranged in an innermost layer and formed by winding. According to the lithium ion battery, a first positive island region and a second positive island region which are not coated with active substances are arranged in a certain distance on the two sides of a positive tab; during winding, the second positive island region and the first positive island region are used for correspondingly wrapping a negative tab and the rear surface of the negative tab respectively, so that the lithium separation when the positive active substances are over against the negative tab is avoided. According to the preparation method, the battery is hotly and coldly pressed before formation, and excess electrolyte in the battery is squeezed into an airbag, so that the hardness of the battery is improved, the layers of membranes, the positive plate and the negative plate are in relatively close contact with each other, the interface impedance and the internal resistance of the battery are reduced, and the power energy density of the lithium ion battery is increased.

A mechanical interface connecting a biological body segment, such as a limb, portion of a limb or other body segment, to a wearable device such as a prosthetic, orthotic or exoskeletal device, is fabricated by quantitatively mapping a characterized representation of the body segment to form a digital representation of the mechanical interface shape and mechanical interface impedance. The mechanical interface includes a continuous socket defining a contoured inside surface and a contoured outside surface, and includes a material having an intrinsic impedance that varies through the material, so that the intrinsic impedance varies along the contoured inside surface.

The invention discloses a current collector carbon coated aluminum foil and its preparation method. A carbon-containing composite layer is arranged on the substrate of the current collector carbon coated aluminum foil, and is combined with the substrate through a binder, wherein the thickness of the carbon-containing composite layer is 1-100mum; the carbon-containing composite layer comprises granular conductive carbon black pre-dispersed by a dispersant, and fibrous conductive carbon; the granular conductive carbon black and the fibrous conductive carbon filled between the layers of the granular conductive carbon black form a netted node form conductive network. The composite layer is tightly combined with the substrate of the aluminum foil, so the conductivity and the corrosion resistance of the aluminum foil are improved, and the aluminum foil is protected from oxidation or chemical corrosion. The preparation method of the aluminum foil comprises the following operations: mixing the conductive carbon black with the dispersant in an organic solvent to pre-disperse, adding the fibrous conductive carbon, uniformly mixing, adding the binder to prepare a slurry, coating on the aluminum foil, and carrying out vacuum drying. The current collector carbon coated aluminum foil enables the interface impedances of the current collector and an active layer to be reduced, the internal resistance of a battery to be reduced, and the cycle life and the ratio performances of the battery to be improved when the aluminum foil is used as a lithium ion battery anode current collector. The aluminum foil has the advantages of simple technology, low cost and wide application prospect.

The invention discloses an all-solid-state lithium ion battery and a preparation method thereof. The all-solid-state lithium ion battery is prepared by an ink-jet printing technology; different components are dissolved into a solvent to prepare slurry; the slurry is put into different ink boxes; designing is carried out by computer program; electrodes and electrolyte are longitudinally printed in a stepwise gradient manner; the electrolyte longitudinally changes in electrode plates in a gradient manner; the interface impedance of an electrode active material / electrolyte can be reduced by the gradient structure distribution of the electrolyte in the electrode plates; deep conduction of lithium ions is facilitated; the capacity property of the active material is put into the greatest play; and other parts, except for a current collector, of the all-solid-state lithium ion battery structure prepared by ink-jet printing form an overall lamination structure. Various components in the lamination structure are in tight contact and regular arrangement, so that the interface impedance is much lower than that of the all-solid-state lithium ion battery which is prepared in a mechanical superposition manner; and the ink-jet printing mode is convenient, fast and suitable for large-scale production.

The invention discloses a positive electrode of a lithium sulfur battery and a preparation method of the positive electrode of the lithium sulfur battery. The positive electrode of the lithium sulfur battery comprises two parts, namely a carbon coating layer with low-active substance content on a current collector and an active layer with high-active substance content. The carbon coating layer on the surface of the current collector can improve the corrosion resistance of the current collector and prevent the current collector from being oxidized or corroded chemically. The positive electrode with the structure reduces the interface impedance of the current collector and the active layer, the electric conduction of the positive electrode of the battery is enhanced, and the volume volatilization of active substance materials is facilitated. The positive electrode with the structure is applied to the lithium sulfur battery, beneficial to the reduction of the internal resistance of the battery, prolongs to the cycle life of the battery and improves the multiplying power property of the battery.

The invention provides a method for preparing a solid polymer electrolyte lithium ion battery. The method comprises the following steps: A, dissolving a high polymer into an organic solvent, and then performing electrostatic spinning to obtain a thin-layer electrostatic spinning fiber membrane on a receiver covered by an anode diaphragm; B, adding a crosslinking monomer, a lithium salt and an initiating agent into an electrolyte solvent, and mixing uniformly to prepare a precursor; C, pouring the precursor prepared in the step B into the electrostatic spinning fiber membrane, and performing curtain coating uniformly in the electrostatic spinning fiber membrane; and D, assembling a solid polymer electrolyte / electrode diaphragm and a counter electrode diaphragm into a cell, putting the cell into a shell or a bag, sealing, heating to realize in situ synthesis of the solid polymer electrolyte, and sequentially performing formation, shaping and degassing processes to prepare a formed battery. The method provided by the invention can be simultaneously used for preparing a gel / all-solid polymer electrolyte lithium ion battery, and the obtained battery is small in interface impedance, high in mechanical strength and high in safety performance.

The invention discloses a solid electrolyte membrane of a lithium ion battery, and relates to the field of lithium ion batteries. The solid electrolyte membrane is composed of a glass ceramic electrolyte and a coating layer with which the surface of the glass ceramic electrolyte is coated. The coating layer is prepared from lithium salt and a polymer material at the molar ratio of 1:5-1:10. The electrolyte membrane can reduce the interface impedance of the full-solid-state lithium ion battery to a great extent, so that the cycling stability of the full-solid-state lithium ion battery is improved, and the service life of the full-solid-state lithium ion battery is prolonged. The invention further discloses a preparation method of the solid electrolyte membrane and the full-solid-state lithium ion battery comprising the solid electrolyte membrane. The solid electrolyte membrane of the lithium ion battery is high in mechanical strength and excellent in electrochemical performance, and meanwhile the preparation technology is simple and convenient to popularize.

The invention discloses a composite lithium ion battery ceramic diaphragm, wherein single-face or double-face electrostatic spinning is carried out on a ceramic coating diaphragm. The preparation method comprises the following steps: step 1, preparing an electrostatic spinning solution; step 2, carrying out electrostatic spinning; and step 3, treating the composite diaphragm obtained by spinning. The electrostatic spinning is carried out on the surfaces of the existing polyolefin ceramic coating diaphragm and non-woven fabric ceramic coating diaphragm, the electrostatic spinning can be used for fastening and constraining ceramic granules to prevent the ceramic granules from dropping, and moreover, the electrostatic spinning is used as a soft buffering layer to perfect the contact of the diaphragm with the surface of an electrode, so as to reduce the interface impedance of the diaphragm and a battery pole piece and help to improve such properties of the battery as rate discharge and cycle life, etc.

The invention discloses a composite solid-state polymer electrolyte and an all-solid-state lithium battery. The composite solid-state polymer electrolyte comprises organic micro-nano porous granules, a polymer having lithium ion conducting capability and a lithium salt; the composite solid-state polymer electrolyte takes the organic micro-nano porous granules as filler; and natural compatibility exists between the organic filler and the polymer matrix. The composite solid-state polymer electrolyte disclosed by the invention has high electrochemical window (4.2-5V), excellent interface stability with a lithium-based negative electrode material, and low interface impedance. The all-solid-state lithium battery, assembled by the composite solid-state polymer electrolyte disclosed by the invention, is high in cycling performance and rate capability.

The invention belongs to the technical field of lithium ion batteries, in particular relates to a gel polymer lithium ion battery which comprises a gel polymer electrolyte, a cathode, an anode and a diaphragm between the cathode and the anode, wherein the gel polymer electrolyte comprises a lithium salt, a non-aqueous solvent and a polymer monomer; the polymer monomer contains at least one epoxy monomer containing epoxy groups and double bonds and at least one acrylic ester monomer; an anode adhesive comprises a polymer of which the main chain or side chain contains amino groups or imino groups. Compared with the prior art, by introducing the epoxy compound as a monomer and adopting a polymer containing amino groups or imino groups as an anode adhesive (epoxy groups react with the amino groups or imino groups to form a cross-linked network), the gel polymer electrotype can be tightly connected with the anode, thus improving the mechanical strength and deformability resistance of the battery, greatly reducing interface impedance of the battery and enhancing the cycle performance and the dynamic performance of the battery.

The invention belongs to the technical field of lithium-ion batteries, in particular to a lithium-ion battery electrolyte and a lithium-ion battery. Three additives, namely an additive A, an additiveB and an additive C, are added in the in the electrolyte, wherein the additive A can improve the cycle performance of a high-nickel material battery and inhibit the battery from increasing internal resistance in high-temperature storage and cyclic processes, the charging and discharging efficiency of the battery in charging and discharging processes can be improved, and self-discharging is reduced; the additive B can form a thin and compact SEI membrane on a negative electrode interface, so that a high-nickel material has relatively low interface impedance when matching with a high-volume high-compaction negative electrode material, and lithium-ions are favorably diffused; the additive C can inhibit a high-nickel battery from producing too much gas so that a battery explosion-proof valveis sprung in the long-term storage process at high temperature, and meanwhile has positive influence on the cycle life of the battery; therefore, the electrolyte guarantees that the battery has a relatively good cyclic life, the internal resistance of the battery in the use process is reduced, and when the battery is used at high temperature, potential safety hazards, which appear as the explosion-proof valve is sprung, are avoided.

The invention relates to the technical field of lithium batteries and in particular relates to a composite negative electrode of a solid-state lithium battery and a preparation method of the compositenegative electrode. The composite negative electrode of the solid-state lithium battery comprises a solid-state electrolyte thin film layer and a lithium negative electrode layer, wherein the lithiumnegative electrode layer comprises a lithium metal negative electrode material; the lithium metal negative electrode material is combined on the solid-state electrolyte thin film layer at a molten state to form the lithium negative electrode layer. The lithium metal negative electrode material is combined on the solid-state electrolyte thin film layer at the molten state to form the lithium negative electrode layer; the wetting performance between the lithium negative electrode layer and the solid-state electrolyte thin film layer can be improved very well and the formation of lithium dendritic crystals is inhibited very well; the safety performance of the lithium battery with a negative electrode structure is improved; meanwhile, the interface impedance between the lithium negative electrode layer and the solid-state electrolyte thin film layer is reduced very well, the migration rate of conductive ions between the lithium negative electrode layer and the solid-state electrolyte thinfilm layer is improved and the conductivity of the lithium negative electrode layer is improved.

The invention belongs to the technical field of lithium ion battery electrolyte, and particularly relates to a preparation method of an integrally formed solid-state battery. The method comprises thefollowing steps: respectively dissolving a modified or unmodified electrode active substance, a conductive agent, a binder, a polymer, a lithium salt and an inorganic electrolyte in an organic solventto obtain electrode slurry; coating a current collector with the electrode slurry, drying, and rolling to obtain an electrode plate; mixing a lithium salt, a polymer, an inorganic filler, a polymericmonomer and an initiator in proportion, and dissolving the mixture in an organic solvent to form electrolyte precursor slurry; coating the electrolyte precursor slurry on the surface of the electrodeplate, and carrying out thermal initiation or photo initiation or heating drying to prepare an electrode and electrolyte integrated structure; and obtaining the solid-state battery cell in a hot pressing manner. According to the invention, the problems of poor physical contact between key material layers and large interface impedance caused by separated multi-layer stacking preparation are effectively avoided.

The invention discloses application of a high ionic conductivity solid electrolyte layer in an all-solid-state lithium ion battery. An assembling step of the battery comprises the following steps: cutting a composite positive electrode and a composite negative electrode which are coated with films, uniformly coating the composite positive electrode or the composite negative electrode with electrolyte slurry, laminating the composite positive electrode and the composite negative electrode, drying the electrodes by blast air, then drying the electrodes in vacuum, baking the electrodes, welding tabs, performing vacuum packaging and cold-thermal pressing to realize close connection between electrolyte layers, and completing preparation of the all-solid-state lithium ion battery. The application has the advantages that the surfaces of the composite positive and negative electrodes are coated with the high ionic conductivity solid electrolyte layer and then are dried and sliced, and the surface of the cut composite positive electrode or composite negative electrode is uniformly coated with the electrolyte layer; before baking, the positive and negative electrodes are assembled, then dried by the blast air and assembled into the battery; and by twice coating of the electrolyte slurry, the problem of a micro short circuit of the full-solid-state battery and the problem of a relativelyhigh interface impedance between the electrolyte and composite positive and negative pole pieces as well as between one electrolyte layer and the other electrolyte layer can be effectively solved.

The invention provides an electrolyte / electrode interface integrated construction technology of an all-solid-state lithium battery. According to the electrolyte / electrode interface integrated construction technology, a polymer electrolyte layer is prepared on a positive electrode material layer in situ; the interface contact between the positive electrode material layer and the electrolyte layer is improved and the interface impedance is reduced, so that the rate performance and the circulating performance of the battery are improved. A construction process of the all-solid-state lithium battery is extremely simplified, the cost is reduced and the interface contact is optimized; meanwhile, the electrical conductivity and the electrochemical stability of polymer electrolyte are improved.

The invention discloses a preparation method of a lithium lanthanum zirconium oxide nanometer fiber, a preparation method of a composite film and solid battery application. Filamentation is carried out on a lithium lanthanum zirconium oxide precursor solution by using a jet airflow and a propelling plant, and the lithium lanthanum zirconium oxide nanometer fiber is obtained after heat treatment is carried out on the collected lithium lanthanum zirconium oxide fiber precursor. Superfine lithium lanthanum zirconium oxide nanometer powder or a lithium lanthanum zirconium oxide nanometer fiber film with certain mechanical property is obtained respectively by regulating the technological parameters and heat treatment temperature of an airflow spinning process. The method is simple in operation and low in cost, and can realize commercialized production. The composite film of the lithium lanthanum zirconium oxide fiber film and polymer provides a continuous lithium ion passage, so that higher ionic conductivity can be provided. The lithium lanthanum zirconium oxide nanometer fiber powder is used for composite ceramic films or composite electrolytes, blockage for membrane holes can be avoided, and higher ionic conductivity can be provided. A solid battery or lithium-ion battery prepared by using the lanthanum zirconium oxide nanometer fiber film or powder is stable in cycle performance, high in rate capability, low in interface impedance and high in stability.

The invention discloses a method for preparing a polymer electrolyte of a flexible lithium-ion battery in situ and an application. The method comprises the steps of firstly preparing a porous membraneof a polymer substrate from a polymer; stirring a functionalized ionic liquid monomer, a non-ionic liquid monomer, a cross-linking agent, a thermal initiator, an ionic liquid and a lithium salt evenly to prepare a colorless transparent precursor solution; immersing the porous membrane of the polymer substrate into the precursor solution, reacting the porous membrane of the polymer substrate immersed into the precursor solution in an inert atmosphere at 60-80 DEG C for 10-24h and forming the polymer electrolyte in situ. A secondary lithium-ion battery employing a gel polymer as the electrolytehas good chemical and electrochemical stability, and the safety performance is greatly improved. The preparation technology can be well simplified through in-situ crosslinking, the compatibility of the electrolyte and an electrode is improved, the interface impedance is reduced and the method is especially suitable for preparing thin batteries of various shapes.

The invention provides a total temperature-range lithium ion battery. The total temperature-range lithium ion battery comprises a multi-tab anode piece having a compound multi-layer coating structure, a multi-tab cathode piece having a compound multi-layer coating structure, a high temperature-resistant diaphragm and a high / low temperature composite electrolyte. Each one of two sides of a part 4 on positive and negative current collectors is orderly coated with a rapid charging / discharging layer 1 (1a, 1b), a transition layer 2 (2a, 2b) and a slow charging / discharging layer 3 (3a, 3b). Through the structure, the total temperature-range lithium ion battery has rapid charging / discharging performances without battery energy density reduction. Through the multi-tab structure, the high temperature-resistant diaphragm and the high / low temperature composite electrolyte, battery ohmic resistance and electrochemical interface impedance are reduced and battery safety is improved. The total temperature-range lithium ion battery can realize normal charging and discharging at a temperature of -40 to 75 DEG C and has excellent low-temperature high-magnification characteristics and high-temperature and long-life performances.

The invention discloses a solid electrolyte membrane and a preparation method thereof. The solid electrolyte membrane comprises a solid electrolyte layer and a compound layer compounded on at least one surface of the solid electrolyte layer; a high-molecular polymer with certain lithium ion conduction capability is selected by the compound layer; and the preparation method comprises the steps of preparing a polymer matrix, of which the porosity reaches 60-90%, of a continuous three-dimensional network structure by adopting a phase separation method; soaking the polymer matrix into slurry containing solid electrolyte powder and pulling out and drying the polymer matrix to obtain the solid electrolyte layer; and coating the surface of the solid electrolyte layer with the compound layer to obtain the solid electrolyte membrane. According to the solid electrolyte membrane, inorganic solid electrolyte particles are embedded into a polymer membrane of the three-dimensional network structure to obtain the solid electrolyte layer with high ionic conductivity and good processability and mechanical property; and meanwhile, the polymer with certain lithium ion conduction capability coats a single side or double sides of the surface of the solid electrolyte layer to reduce the interface impedance.

The invention relates to a lithium ion battery electrolyte and a lithium ion battery, and belongs to the technical field of lithium ion batteries. The lithium ion battery electrode comprises an organic solvent, an electrolyte lithium salt, a low-impedance additive and a functional additive, wherein the low-impedance additive comprises lithium difluorophosphate and lithium difluoro bis(oxalato) phosphate, the functional additive is an arbitrary one or a combination of tris(trimethylsilyl) borate and tris(trimethylsilyl) phosphate, and the functional additive accounts for 0.1-4% of the total mass of the lithium ion battery electrolyte. The lithium ion battery electrolyte can participate in negative electrode film formation, the interface impedance of the electrolyte is reduced, and the low-temperature performance of the electrolyte is improved; and a flexible and high-temperature stable electrode interface film also can be formed on a surface of a high-capacity silicon carbon composite negative electrode material, the breakage of an SEI film caused by silicon expansion during the circulation process is timely repaired, and the cycle property of the silicon carbon negative electrode lithium ion battery is improved.

The invention relates to the technical field of materials for li-ion batteries. The invention discloses a modified current collector with nano graphite coating including foils of a current collector. The foil of a current collector has a coating containing nano graphite on a single side or both sides. Nano graphite is applied in the invention as a main functional material of the coating. The characteristics of highly-graphitized graphite are reserved by the nano graphite material.The electric conductivity and heat conductivity of the nano graphite material are excellent. Meanwhile, dispersity and coating effect or the like of a graphite material can be improved because of the nanocrystallization characteristic. The material can be used as a coating material. In addition, the cost of nano graphite material is lower than that of graphene, so the material is applicable to industrial promotion. The nano graphite material can decrease the interface impedance between a current collection and an active material, reduce internal resistance of batteries and improve the cycle life and rata capacity of batteries when being used in lithium ion batteries.

The invention provides an all-solid-state lithium ion battery with low interface impedance and high compatibility. The battery comprises a composite positive pole piece and a composite negative pole piece, wherein the composite positive plate and the composite negative plate are a mixture of an active substance and solid electrolyte with a certain concentration gradient, the concentration gradientis that the concentration of the active substance is gradually reduced from a current collector to the outside, the solid electrolyte is gradually increased, and the outermost layer is only a solid electrolyte layer. In order to achieve interfacial compatibility of the positive and negative composite pole pieces, a surface of the outermost solid electrolyte layer of the composite pole piece is designed into a concave-convex groove, and the concave-convex surface is coated with low-melting polymer solid electrolyte; and lastly, the composite positive pole piece and the composite negative polepiece are tightly combined in a hot-pressing manner to assemble the battery. The battery can effectively solve a problem of compatibility between an electrode material and an electrolyte layer and a problem of large interface impedance of a solid-state battery, and thereby the cycling stability of the solid-state battery is improved.

The invention discloses electrolyte, a preparation method for the same and a high-voltage lithium ion battery. The electrolyte mainly comprises an organic solvent, conductive lithium salt and an additive, wherein the organic solvent is prepared from more than one of a cyclic carbonate solvent, an aromatic hydrocarbon solvent and a linear solvent; the concentration of the conductive lithium salt in the organic solvent is 0.8 to 1.5mol / L; the using amount of the additive is 0.1 to 10.0 percent based on the weight of the organic solvent, and the additive is a halogenated cyanophenyl compound. After the additive is added into the electrolyte, a polymer film can be formed on the surface of each of a positive electrode and a negative electrode, so that the interface impedance of the electrodes / electrolyte is reduced, the decomposition of the electrolyte on the surface of an electrode material is suppressed, and the prolonging of cycle life of the high-voltage lithium ion battery (higher than 4.4V), the improvement of high / low-temperature performance of the high-voltage lithium ion battery and the suppression of gas expansion of the battery are facilitated.

The invention relates to a composite solid electrolyte membrane and a preparation method and application thereof. The composite solid electrolyte membrane has a sandwich structure including a base membrane in an intermediate layer and solid polymer electrolytes coated on both sides of the base membrane. Ceramic ionic conductor powder is anchored in the pores of the base membrane by a binder. The invention utilizes the structural characteristic that the base film has certain pore distribution, the ceramic ionic conductor powder is embedded into the pores and anchored by the binder to form a stable integrated structure, which not only retains the original barrier effect, but also effectively improves the room temperature ionic conductivity and mechanical strength without destroying the flexibility of the diaphragm itself, and synthesizes the advantages of the diaphragm and the ceramic ionic conductor powder. The solid polymer electrolytes with ionic conductivity are coated on both sidesof the diaphragm to reduce the contact interface impedance between the diaphragm and positive and negative electrodes.

The invention provides an additive for a battery electrolyte. The additive at least comprises one of compounds shown in structural formulas (1)-(7). According to the additive for the battery electrolyte, a low-impedance protective film can be formed on the surface of an electrode, side reactions of the electrode and the electrolyte are inhibited, the interface impedance is reduced, the high-low temperature performance is considered, and the overall output performance of a lithium ion battery is improved.

The invention discloses a production method of a sandwich-like structure solid polymer electrolyte membrane, and an application of the sandwich-like structure solid polymer electrolyte membrane in a solid-state lithium ion battery, and belongs to the technical field of solid-state lithium ion batteries. The production method comprises the following steps: taking a polymer and an alkali metal saltaccording to a mass ratio of (2-6):1, dissolving the polymer and the alkali metal salt in acetonitrile, and performing stirring and uniform mixing to obtain a solution A; taking half of the solution A, adding a plasticizer, and performing full stirring and uniform mixing to obtain a solution B; and respectively coating two sides of a support membrane with the solution A and the solution B, and drying the coated support membrane in a vacuum drying box for 12-24 h to produce the sandwich-like structure solid polymer electrolyte membrane. The invention also discloses a production method of a solid-state lithium ion battery using the sandwich-like structure solid polymer electrolyte membrane. The produced sandwich-like structure solid polymer electrolyte membrane has the advantages of high ionconductivity, good mechanical strength, low interface impedance, good interfacial stability, and effective improvement of the cycling stability of the solid-state lithium ion battery.

The invention discloses a preparation method of a novel composite positive electrode. The preparation method comprises: 1, preparing a composite solid electrolyte solution, 2, mixing the composite solid electrolyte solution, a positive electrode active material, a conductive agent and a dispersing agent according to a preset ratio, carrying out uniform stirring, coating a positive electrode current collector with the mixture and carrying out drying to obtain a composite positive electrode, and 3, coating the composite positive electrode with the composite solid electrolyte solution obtained bythe step 1 and carrying out drying to obtain a composite positive electrode with the solid electrolyte. The invention also discloses the novel composite positive electrode and a solid lithium batteryusing the same. The preparation method keeps the soft contact between the solid electrolyte and the electrode active material and soft contact between the solid electrolyte and the battery electrodeand reduces the interface impedance between the solid electrolyte and the electrode active material and between the solid electrolyte and the battery electrode.