672 results about "Lithium ion transport" patented technology

The invention discloses a silicon-carbon negative electrode material, porous carbon and a preparation method, the porous carbon is prepared by mixing ammonium fluoride and a pre-carbonized material to prepare a premix; and putting the premix in an inert atmosphere, and carrying out pre-activation, drying, carbonization, activation and crushing treatment to obtain the composite material. And uniformly depositing the nano silicon particles into the porous carbon skeleton through a mature CVD (Chemical Vapor Deposition) process to obtain the silicon-carbon composite material. Fluorine and nitrogen co-doping modification can increase the defect degree of a carbon skeleton, efficiently relieve mechanical stress accompanied by lithium storage volume expansion of the silicon negative electrode in a micro scale, provide abundant lithium ion transport and mass transfer channels and enhance the conductivity of porous carbon, and ammonium fluoride is used as a supplementary activator besides water vapor, so that the porosity of the porous carbon is further improved, and the conductivity of the porous carbon is improved. An effective space is provided for uniform deposition of silicon, the fluorine-containing carbon layer can induce formation of a high-stability SEI film rich in LiF on the surface of the nano silicon material, and the interface stability and coulombic efficiency of the silicon negative electrode are further improved.

The invention discloses a difunctional filler synergistically enhanced polymer solid electrolyte and a solid-state battery, and belongs to the field of solid-state batteries. The electrolyte adopts a polymer matrix, a lithium salt and two functional fillers: the first filler has a high dielectric constant, and can accelerate dissociation of the lithium salt, fix negative ions of the lithium salt and improve the transference number of lithium ions under the action of self polarization; and the second filler has high electrochemical window and ionic conductivity, can inhibit high-voltage decomposition, and is adaptive to a high-voltage positive electrode material. Through cooperation and balance design of the two kinds of filler, ion transmission, interface stability and high-pressure compatibility can be considered at the same time. In addition, the invention further designs a composite negative pole piece, the surface of the negative pole piece is coated with the solid electrolyte, and the ion transmission kinetics in the pole piece can be remarkably improved. On the basis, the invention develops a high-performance solid-state battery which is excellent in electrochemical performance and can play an important role in the fields of consumer electronics, electric automobiles, energy storage systems, low-altitude flight and the like.

The invention discloses a storage battery charging control system and a control method thereof, and relates to the technical field of storage battery charging, and the control method comprises the following steps: firstly, comprehensively obtaining multi-modal sensing data from a storage battery; preprocessing the obtained original data, and extracting key features beneficial to identification of lithium ion migration blocking from the preprocessed data under a detection window; and inputting the extracted features into a pre-learned deep learning model, and carrying out intelligent assessment on the lithium ion migration blocking risk in the storage battery charging process through the deep learning model. Multi-modal sensing data and a deep learning model are utilized, the lithium ion migration blocking risk is accurately identified, an electrochemical polarization rapid change factor and an electrode dynamics non-equilibrium factor are extracted to generate a deposition index and classify the deposition index, a charging strategy is dynamically adjusted, high-current charging is carried out during normal migration, and current is reduced during blocked migration. Lithium deposition and dendritic crystal risks are reduced, efficiency and safety are improved, and the service life of the battery is prolonged.

The invention provides an ionic liquid additive for a solid-state lithium metal battery electrolyte and a method for preparing the solid-state lithium metal battery electrolyte by using the ionic liquid additive. The bistrifluoromethanesulfonyl imide salt containing terphenyl and lithium carboxylate obtained through Michael addition reaction is captured by open metal sites of the MOF material UiO-66-NH2, the structural stability of the material can be improved, more transmission channels are provided for lithium ions, and therefore the transference number of the lithium ions is increased, the performance of the lithium metal battery is improved, and the service life of the lithium metal battery is prolonged. Especially in the aspect of charge and discharge rate. The electrolyte material disclosed by the invention has good stability with lithium metal, so that electrolyte decomposition can be prevented, and an unstable phenomenon, such as lithium dendrite growth, on the surface of an electrode can be avoided, so that a lithium metal battery can show excellent electrochemical performance, including better cycling stability, high coulombic efficiency and longer battery life.

Disclosed in the present application is an ionic liquid type waterborne polyurethane dispersion, which is characterized in that a cationic waterborne polyurethane dispersion is obtained by grafting a cationic liquid to a waterborne polyurethane resin main body by means of a chemical reaction, wherein the cationic liquid is derived from an ionic liquid alcohol. Further provided in the present application are a preparation method for and the use of the ionic liquid type waterborne polyurethane dispersion. In the present application, the cationic liquid is grafted to the waterborne polyurethane resin main body by means of a chemical reaction, thereby solving the problems of low conductivity and a low lithium ion transference number of a polymer-based electrolyte.

The invention belongs to the field of electrochemical energy, and relates to polyurethane with self-repairing capability, a solid electrolyte, a composite electrode and a preparation method, a soft segment part of the self-repairing polyurethane-based solid electrolyte has good segment motion capability, and compared with polyethylene glycol, the crystallinity is greatly reduced; and the ionic conductivity and the lithium ion transference number are greatly improved. The dynamic disulfide bond and the hydrogen bond of the hard segment part jointly form a dynamic reversible macromolecular network, so that the mechanical strength is considered, and the tensile property, the self-healing property and the repeatable processing property are good. The self-repairing polyurethane-based solid electrolyte has relatively high ionic conductivity and lithium ion transference number, and can be cured on an electrode in situ to eliminate the interface contact problem of the electrolyte and the electrode, and the positive electrode and the negative electrode of the battery are healed into a whole through the self-healing capability of polyurethane, so that the performance of the battery is greatly improved, and the service life of the battery is prolonged. And the material has a good application prospect in all-solid-state lithium batteries.

The invention provides a lithium-rich manganese-based material for an all-solid-state battery as well as a preparation method and application thereof, the preparation method comprises the following steps: mixing and drying a lithium-rich manganese-based carbonate precursor, a dopant and a first solvent to obtain a doped lithium-rich manganese-based carbonate precursor, and then sintering and washing to obtain a pretreated precursor; and carrying out ball milling on the pretreated precursor, mixing with a lithium source, and calcining to obtain the submicron single crystal type lithium-rich manganese-based positive electrode material, and mixing the single crystal type lithium-rich manganese-based positive electrode material, a metal source coating agent and a second solvent, then removing the second solvent, and roasting to obtain the lithium-rich manganese-based material for the all-solid-state battery. According to the preparation method disclosed by the invention, through internal doping of rare earth ions, design of a submicron single crystal structure and surface in-situ coating, the migration speed of lithium ions and the stability of the crystal structure can be improved, side reactions of an interface are reduced, and the stability of the interface is improved.

The invention discloses a composite separation membrane for enriching < 6 > Li isotope and application. The composite separation membrane comprises a functional membrane and at least one supporting membrane; the functional film comprises a plurality of pore channels penetrating through the first surface and the second surface of the functional film, and the pore channel diameter of each pore channel is 0.4-0.7 nm; a lithium ion trapping functional group or a macrocyclic compound and a derivative thereof are modified at an inlet of the first surface of the pore channel. The strength of the lithium isotope separation effect depends on the diameter of a pore channel of the composite separation membrane and functional groups modified at an inlet, does not change along with the migration time and the lithium ion migration proportion, and has long-term continuous stability.

The invention provides an all-solid-state battery three-dimensional electrode preparation method based on aerosol jet printing, and the method comprises the following steps: constructing a three-dimensional porous frame by using a conductive skeleton material through an aerosol jet printing technology; depositing an active material and a solid electrolyte on the surface of the frame layer by layer to form a gradient distribution layer; generating an interface transition layer by adopting ultraviolet curing or rapid heat treatment; and in combination with a closed-loop feedback control system, deposition parameters are dynamically adjusted. A conductive active material and a solid electrolyte are uniformly distributed on the surface of a three-dimensional porous framework in a layer-by-layer deposition manner through an aerosol jet printing method, and the solid electrolyte and an electrode material form a close contact interface by accurately controlling a jet path, a nozzle diameter and a material deposition rate; the interface side reaction easily caused by traditional high-temperature sintering is eliminated, and the interface impedance is reduced; and furthermore, the transmission efficiency of the lithium ions at the interface is improved through an ultraviolet curing or rapid heat treatment process.

The invention discloses a zirconium-based metal organic framework (Zr-MOF) composite semi-solid electrolyte material prepared based on an electrostatic spinning technology and application of the zirconium-based metal organic framework (Zr-MOF) composite semi-solid electrolyte material. The material is composed of a three-dimensional polymer fiber network, surface-coated Zr-MOF nanoparticles and an organic liquid electrolyte solution, a polymer matrix provides mechanical support, and Zr-MOF micropores and a liquid electrolyte form a multistage ion transmission channel. The preparation method comprises the processes of electrostatic spinning forming, in-situ Zr-MOF synthesis and gradient pressure electrolyte infiltration. The ionic conductivity of the material at 25 DEG C reaches 1.2 * 10 S / cm, the lithium ion transference number is 0.65, the capacity retention ratio after 500 cycles is greater than or equal to 90%, and the material is suitable for high-energy-density lithium ion batteries and flexible energy storage devices through acupuncture safety tests.

The invention discloses a multi-scale synergistically enhanced self-healing solid polymer electrolyte and a preparation method thereof, and belongs to the technical field of electrolyte materials. The preparation method of the electrolyte comprises the following steps: S1, adding the eight-arm star polymer, the carborane lithium salt, the neutral plastic crystal additive, the ionic liquid monomer and the crown ether functionalized boron alkene two-dimensional filler into a mixed solvent to form electrolyte slurry; s2, uniformly coating a base material with the electrolyte slurry to form a wet film, and drying the wet film; s3, transferring the dried membrane to an environment filled with inert gas, and initiating in-situ polymerization of an ionic liquid monomer by using ultraviolet irradiation to form a polyionic liquid nanofiber network; and S4, placing the membrane under a vacuum condition at a constant temperature of 120 DEG C for 5 hours to obtain the solid polymer electrolyte membrane. The solid polymer electrolyte membrane provided by the invention overcomes the problems of low ionic conductivity, low lithium ion transference number, insufficient mechanical properties, poor interface stability, narrow electrochemical window and the like of the existing solid polymer electrolyte.

The present invention relates to a polymer solid electrolyte diaphragm with a multilayer structure and a preparation method and application thereof. The diaphragm structure is a multilayer structure of polymer layer / skeleton material layer / polymer layer, wherein the skeleton material layer is mainly a skeleton material and is also infiltrated by the polymer layer; the polymer layer is a polymer material with lithium ion conductivity. In the multilayer structure of the present invention, a small amount of liquid electrolyte remaining in the rich gaps of the metal-organic framework material tightly arranged in the skeleton material layer forms a liquid film, which can provide a liquid transmission channel when the solid electrolyte diaphragm transmits lithium ions, improve the lithium ion transmission rate and lithium ion migration number of the electrolyte diaphragm, and at the same time, the good mechanical strength and thermal stability of the fiber cross-linking structure can improve the mechanical properties and flame retardant properties of the polymer electrolyte diaphragm. The obtained lithium metal battery and lithium ion battery have a longer cycle life and a higher specific capacity. At the same time, the process of the present invention is simple and easy to operate, and is suitable for industrial production.

Disclosed in the present invention are a negative electrode sheet and a manufacturing method therefor, and a lithium-ion battery. The negative electrode sheet comprises a current collector, a first active material layer applied to coat at least one surface of the current collector, and a second active material layer applied to coat the surface of the first active material layer. The first active material layer comprises a silicon-based material, and the second active material layer comprises vertically oriented graphite. According to the present invention, the first active material layer increases the energy density of a battery and avoids the demolding risk of the second active material layer; a second active material accelerates lithium ion transport, thereby adapting to a large volume change in a charging and discharging process, shortening the transport path of electrons in the vertical direction, and improving the electrical conductivity of an electrode and the electron collection efficiency of the battery; and an electrolyte is in full contact with the electrode, thereby increasing active sites, providing a certain buffer space for the expansion of the silicon-based material in the first active material layer, reducing the expansion rate of a battery cell, ensuring the structural stability, and improving the cycle performance and charging capability of the battery cell.

The invention belongs to the technical field of new energy materials, and particularly relates to siloxane crosslinking modified polyether solid electrolyte and a preparation method thereof. According to the solid electrolyte, the electrophilic ring-opening polymerization reaction of a polymer monomer with an epoxy group is utilized, siloxane is used as a cross-linking agent, polyether chain structures are connected together to form a cross-linked network structure, the ionic conductivity can be increased, and the mechanical strength and the high-temperature dimensional stability can be improved; the lithium ion transference number is increased, the polarization is reduced, and the battery rate capability is improved; the oxidation stability of the electrolyte is improved; the decomposition reaction of polyether at high temperature is inhibited; the thermal stability and the flame retardant property of the polymer electrolyte are remarkably improved, so that the safety of a solid-state battery is improved.

The invention relates to the technical field of battery electrolytes, in particular to a flame-retardant solid polymer electrolyte and a preparation method and application thereof and a gel polymer electrolyte.The preparation method comprises the steps that a lithium salt, a polymer monomer, a cross-linking agent, an initiator, an additive and an organic solvent are mixed, heated and stirred to be uniform, and a precursor is obtained; and introducing a catalyst into the precursor to polymerize and cure the precursor to obtain the solid polymer electrolyte. The solid polymer electrolyte prepared by the invention has extremely strong flame retardant property; a unique cross-linked structure enhances the mechanical strength, and destroys the regularity of a polyether chain segment, so that the polyether chain segment is in an amorphous state, and therefore, the polyether chain segment has high ionic conductivity; due to the introduction of bicyclic carbonate, the oxidation stability is enhanced, high stability is shown on a high-voltage positive electrode, and the lithium ion transference number of the electrolyte is also increased to a certain extent; and finally, the assembled battery shows excellent cycling stability and rate capability.

Disclosed in the present application is a preparation method for a cobalt-free lithium-rich manganese-based positive electrode material. The preparation method comprises: mixing a nickel manganese hydroxide precursor with a lithium source, adding a zinc additive and a fluorine additive thereto, and uniformly mixing same to obtain a premixed material; and heating the premixed material to a first calcination temperature for calcination in an oxidizing gas atmosphere, then continuously heating the premixed material to a second calcination temperature for calcination, and after naturally cooling same, obtaining a cobalt-free lithium-rich manganese-based positive electrode material. Further disclosed in the present application is a cobalt-free lithium-rich manganese-based positive electrode material obtained by means of the preparation method. In the present application, Zn-ion lithium site and transition metal site double-site doping and F-ion oxygen site doping are used, such that the first coulombic efficiency is improved, lithium ion transport is promoted, and the rate capability and cycle performance of the material are improved; in addition, expensive and harmful cobalt is removed, thereby preparing the cobalt-free lithium-rich manganese-based positive electrode material by means of a simple solid-phase sintering method. The process flow is simple, the production cost is low, and industrialization is easier to achieve.

The present invention relates to an in-situ synthesized high-voltage resistant gel polymer electrolyte, belonging to the technical field of gel polymer electrolytes. The electrolyte is prepared by the following method: in a light-proof protective gas atmosphere with oxygen and water contents less than 1 ppm, PETT and divinyl adipate are added to an electrolyte in a substance ratio of 1: (1-4) to obtain a mixed solution a, wherein the concentration of PETT is (0.2-5) mol / L, and then a free radical polymerization photoinitiator is added and mixed to obtain a mixed solution b, and bubbles in the mixed solution b are removed to obtain a precursor solution; the precursor solution is used to infiltrate the positive electrode material in the positive electrode for 0.5h-2h, and then visible light is used for irradiation for 0.2h-1h to obtain the electrolyte on the positive electrode. The electrolyte has good ionic conductivity and lithium ion migration number, and has a wide electrochemical window, and has good interface compatibility with the positive electrode.

The invention discloses a preparation method of an intrinsically safe polymer electrolyte and a solid-state battery thereof, and belongs to the field of preparation of solid-state lithium metal batteries. The solid polymer electrolyte is of a 1M (xA + yB) + (z1C + z2D) type, x accounts for 14-15 wt%, y accounts for 1-2 wt%, z1 accounts for 70-72 wt%, z2 accounts for 11-12 wt%, A and B are lithium salts, C is a fluorine-containing monomer, D is a cross-linking agent, the fluorine-rich monomer, the cross-linking agent and the lithium salts are mixed, no electrolyte is added, an in-situ thermal polymerization method is adopted to prepare the intrinsic safe solid polymer electrolyte with high safety and high voltage resistance, and meanwhile, the electrolyte is of a three-dimensional chain network structure. Therefore, the safety performance of the electrolyte is effectively enhanced, the migration activation energy of lithium ions is reduced, and the ionic conductivity is improved. The core problems that an existing traditional battery is poor in safety performance, poor in high-voltage tolerance, large in interface impedance, out-of-control in lithium dendrite growth and the like are solved.

The invention provides a negative pole piece and a preparation method thereof, the negative pole piece comprises a current collector, a first active material layer and a second active material layer, the current collector is coated with the first active material layer and the second active material layer in sequence, and the gram volume of the first active material layer is larger than that of the second active material layer. The expansion rate of the first active material layer is greater than that of the second active material layer; the first active material layer comprises an alloy A supported by a carbon material; the second active material layer includes hard carbon. According to the negative pole piece, the alloy A supported by the carbon material combined by different alloys is prepared, so that the alloy A supported by the carbon material has different expansion coefficients and gram volumes, and the larger the gram volume is, the larger the energy density is; by preparing the N-doped and P-doped hard carbon, the conductivity of the material and the first effect of the lithium ion battery can be greatly improved, electron and lithium ion transport channels in the hard carbon are increased, the capacity of the material is effectively improved, and the performance of the battery adopting the negative pole piece is greatly improved.

The invention discloses a preparation method of a composite solid electrolyte membrane, and belongs to the technical field of solid lithium batteries, the composite solid electrolyte membrane is formed by uniformly stirring and compounding a polymer matrix, a lithium salt, an inorganic filler SiO2 aerogel and a solvent, the ionic conductivity of the membrane can be effectively improved by modifying the molecular structure of a polymer, and the ionic conductivity of the membrane can be effectively improved by using the SiO2 ceramic inorganic filler. The mechanical strength of the composite solid electrolyte membrane is improved; the prepared composite solid electrolyte membrane is good in electrochemical performance, the room-temperature ionic conductivity can reach 2.3 * 10 <-4 > S / cm, the lithium ion transference number can reach 0.78, the composite solid electrolyte membrane has a wide electrochemical window, the preparation process of the composite solid electrolyte membrane is simple, the stability of an interface between the composite solid electrolyte membrane and a positive electrode and a negative electrode of a battery is good, and the composite solid electrolyte membrane can be applied to the field of lithium ion batteries. The assembled total battery has good cycle stability, and the capacity retention rate can reach 82.3% after 400 cycles.

The invention discloses a preparation method and application of a composite PVDF-HFP and polylysine nanofiber diaphragm, and belongs to the technical field of lithium batteries. The composite material is prepared by blending polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and polylysine and then carrying out an electrostatic spinning process. The PVDF-HFP is utilized to provide excellent mechanical strength and chemical stability, rich polar amino functional groups in a polylysine molecular chain are utilized to improve the lyophilic property of the membrane, and anions in an electrolyte are fixed through an intermolecular acting force, so that the transference number of lithium ions is increased, and the lithium ions are induced to be uniformly deposited. The nanofiber membrane combines the characteristics of PVDF-HFP and polylysine, has high porosity, good thermal stability and excellent interface compatibility, can effectively inhibit the growth of lithium dendrites and prevent the diaphragm from being punctured, and can significantly prolong the cycle life and improve the safety performance of the lithium metal battery when being applied to the lithium metal battery.

The invention discloses a cellulose-based lithium ion battery diaphragm capable of promoting lithium ion migration as well as a preparation method and application of the cellulose-based lithium ion battery diaphragm. The method comprises the following steps: dissolving a plant fiber raw material into a prepared alkali alcohol urea solvent, and then introducing a fluorine-containing modifier and a cyano-containing modifier to modify the plant fiber raw material; and then coating the surface of a polytetrafluoroethylene film with the obtained modified cellulose solution for preheating and shaping, then dipping in water to finish final shaping of the diaphragm and removal of non-cellulose components, and finally performing hot-pressing and drying to remove moisture, thereby obtaining the cellulose-based lithium ion battery diaphragm capable of promoting lithium ion migration. A fluorine-containing group and a cyano-containing group are simultaneously introduced into a cellulose molecular chain, so that the lithium ion migration promoting effect and the electrochemical performance of the battery diaphragm can be effectively improved.

The invention discloses a spherical lithium iron phosphate positive electrode material and a preparation method thereof, and belongs to the technical field of lithium batteries, and the spherical lithium iron phosphate positive electrode material is of a multi-layer coating structure; the spherical lithium iron phosphate positive electrode material sequentially comprises spherical lithium iron phosphate particles, a nanoscale nickel-cobalt-manganese coating layer and a carbon layer from inside to outside. The spherical lithium iron phosphate positive electrode material has relatively high tap density and relatively large specific surface area, so that solid-phase diffusion paths of lithium ions among lithium iron phosphate particles can be reduced, and the contact resistance of the particles is reduced; the nanoscale nickel-cobalt-manganese coating layer can improve the overall electronic conductivity and lithium ion diffusion rate and reduce lithium ion migration barriers; and the outermost carbon layer can form a high-conductivity network and can also be used as a physical barrier to maintain the structural stability of the material, so that the influence of a low-temperature environment on the transmission efficiency of lithium ions and electrons is further reduced, and the low-temperature performance of the spherical lithium iron phosphate positive electrode material is improved.

The invention provides a modified sulfide solid electrolyte and a preparation method and application thereof.The modified sulfide solid electrolyte comprises lithium thioborate crystals, composite grain boundaries are contained between the lithium thioborate crystals, and lithium iodide is contained in the composite grain boundaries. The structures of crystal lattices and composite crystal boundaries in the modified sulfide solid electrolyte are stable, so that the lithium ion migration capability of the modified sulfide solid electrolyte can be improved, and the ionic conductivity of the modified sulfide solid electrolyte is obviously improved.

The invention relates to the technical field of lithium ion batteries, and particularly discloses a preparation method of a novel functional diaphragm of a lithium ion battery, which comprises the following steps: S1, preparing 2, 4, 6-trihydroxybenzene-1, 3, 5-tricarboxaldehyde; s2, a Tp-BD-COF material is prepared from 2, 4, 6-trihydroxybenzene-1, 3, 5-tricarboxaldehyde, and the Tp-BD-COF material is prepared from 2, 4, 6- S3, a Tp-BD-COF / Celgard diaphragm is prepared through the Tp-BD-COF material; s4, applying the Tp-BD-COF / Celgard diaphragm to the assembly of the lithium ion battery; and S5, carrying out electrochemical pre-lithiation treatment on the Tp-BD-COF / Celgard diaphragm. The diaphragm provided by the invention can effectively block shuttling of anions, realize hindering of transmission of lithium salt anions and uniform transmission of lithium ions, so that the transference number of the lithium ions is increased, generation of lithium dendrites is effectively inhibited, good electrochemical performance is realized, polarization caused by different ion gradients is reduced, interface stability is improved, and the performance of the lithium ion battery is improved. And the capacity and the cycle performance of the lithium ion battery can be remarkably improved while the proton conductivity is excellent.

The invention relates to the technical field of inorganic material preparation and new energy materials, and particularly discloses a lithium metal battery composite solid electrolyte as well as a preparation method and application thereof. Lithium niobate with high lithium ion conductivity and high dielectric constant is used as an inorganic filler, polyvinylidene fluoride-co-hexafluoropropylene is used as a polymer matrix, and the lithium metal battery composite solid electrolyte is prepared. The lithium metal battery solid electrolyte with a continuous lithium ion transport path is constructed through a freeze casting technology, the dielectric constant of the solid electrolyte is effectively improved by adding the dielectric inorganic filler lithium niobate, lithium salt dissociation is promoted, preparation of the modified electrolyte can be simply completed on a large scale, industrial expansion is facilitated, coulombic efficiency is improved, and the lithium metal battery solid electrolyte is suitable for industrial production. According to the present invention, the lithium metal battery electrolyte meets the industrial requirement on the high lithium utilization rate, the lithium negative electrode can be well protected, the cycle life of the lithium electrode can be improved, the battery electrolyte and the lithium electrode show the good interface compatibility and the good cycle stability, and the new feasible way is provided for the application of the lithium metal battery.

The invention relates to the technical field of lithium ion batteries, in particular to a preparation method of an interface-modified high-rate lithium iron phosphate positive electrode material, which is used for solving the problems of low interface impedance, low rate capability and low energy density of the existing lithium iron phosphate. According to the preparation method, zirconium-niobium co-doped iron phosphate is used as a precursor of the lithium iron phosphate positive electrode material, a lithium ion diffusion channel is widened, the lithium ion diffusion coefficient is improved, meanwhile, an olivine structure framework is provided, a wider tunnel space is provided for lithium ion migration, zirconium-niobium provides additional electrons, and the electron conductivity is improved through cooperation of the zirconium-niobium co-doped iron phosphate and the olivine structure framework; li2ZrCl6-LiCl interface modification can isolate sulfide electrolyte from being in direct contact with a positive electrode material, and interface side reaction is inhibited; carbon nanotube coating can enhance the conductivity, reduce erosion, improve the diffusion coefficient of Li < + > and the stability of the material structure, and improve the charge-discharge rate.

The invention discloses a preparation method and application of a positive electrode lithium supplement agent, the positive electrode lithium supplement agent is of a core-shell structure, and a core layer comprises lithium-rich metal materials such as lithium-rich lithium ferrite, lithium-rich lithium nickelate and lithium-rich lithium manganate; and a shell layer comprises organic lithium salt materials such as lithium bis (oxalato) borate, lithium bis (fluorosulfonyl) imide, lithium difluorophosphate and lithium difluorobis (oxalato) phosphate. The lithium-rich metal material lithium supplementing agent is coated with the organic lithium salt lithium supplementing agent which is also used as the lithium supplementing agent, so that the lithium-rich metal material is prevented from being in contact with air, and the environmental stability of the lithium-rich metal material is improved; through chelation of specific groups and transition metal ions, the structural stability of the lithium-rich metal material is improved, a lithium ion transmission path is fixed, the capacity of the lithium supplement agent for the lithium-rich metal material can be exerted to the maximum extent, and the organic lithium salt also has a lithium supplement effect, so that the migration rate of lithium ions can be further improved, and the lithium supplement effect is improved. The lithium supplementing effect of the two lithium supplementing agents greatly improves the energy density and the cycling stability of the battery.

The invention belongs to the technical field of battery diaphragms, and provides a composite diaphragm and a preparation method thereof, and a secondary battery, the composite diaphragm comprises a base membrane and a gradient aperture coating arranged on at least one surface of the base membrane; the gradient aperture coating is prepared from a self-polymerized microporous polymer; the gradient aperture coating comprises a nanopore layer and a composite pore layer, and the nanopore layer is located between the base membrane and the composite pore layer; the nanopore layer comprises nanopores, and the composite pore layer comprises micron pores and nanopores which are interspersed with each other. Through the design of the gradient aperture coating, the composite diaphragm has an excellent blocking effect of transition metal cations and large-volume anions, meanwhile, the lithium ion transference number is high, the internal resistance is relatively low, the electrolyte wettability and the heat resistance are excellent, the cycle performance of the secondary battery comprising the composite diaphragm can be improved, and the service life of the secondary battery can be prolonged.

The invention belongs to the technical field of electrolyte materials, and particularly relates to a pH response biopolymer solid electrolyte as well as a preparation method and application thereof. The pH-responsive degradable biopolymer is taken as a main raw material, and one or more functional groups such as pyridine, sulfonic acid, carboxyl, tertiary amine, phosphoric acid and the like are contained. The organic acid and the organic acid salt are selected to adjust the pH value of a medium around the electrolyte, and the contraction / stretching behavior of a molecular chain is influenced by changing the ionization degree of the electrolyte, so that an interpenetrating polymer network structure is formed. The polar functional group of the biopolymer affects the migration behavior of lithium ions under different pH conditions, so that the migration rate and migration quantity of the lithium ions are increased, and the cycle performance of the battery is improved. The electrolyte is suitable for high-performance energy storage devices such as a lithium ion battery, can effectively improve the battery performance, reduces the environmental pollution, and has relatively strong green and environment-friendly advantages.