35 results about "High electrolytes" patented technology

The invention relates to the technical field of solid-state batteries, in particular to oxyhalide solid-state electrolyte as well as a preparation method and application thereof. The method comprises the following steps: taking molten salt LiaMbXc as a raw material, reacting with an oxide AdOf in a molten state, removing steam impurities by utilizing a high-temperature vacuumizing mode, and cooling to prepare the oxyhalide solid electrolyte; according to the invention, the molten salt raw material is molten at high temperature to form the ion melt, and the oxygen element is introduced to replace part of halogen, so that the hardness of the target electrolyte is reduced after cooling, the deformability at room temperature is improved, and the obtained electrolyte is high in conductivity and wide in antioxidant electrochemical window. The prepared oxyhalide solid electrolyte is used for preparing a positive electrode, the adhesion force between the electrolyte and positive electrode material particles, the actual microscopic contact area and the ion migration rate are improved through melt permeation, the problem of a positive electrode interface is effectively relieved, and the electrochemical performance of an all-solid-state battery is improved.

The invention relates to the technical field of preparation devices, and discloses a solid electrolyte preparation device which comprises a shell, a supporting table is fixedly connected to the circumferential surface of the shell, and a discharging pipe is fixedly connected to the circumferential surface of the shell; the device comprises a shell, a protective cover is arranged at the top of the shell, a stirring device is arranged at the top of the shell, a crushing device is arranged on the inner wall of the shell, and a dredging device is arranged on the inner wall of the shell. And meanwhile, the rotating rod rotates to drive the rotating plate II to rotate, so that the mixing effect of the electrolyte powder can be enhanced, and the chemical reaction of the electrolyte powder can be uniformly generated in the whole material system in the subsequent sintering reaction process.

A process and system for recovering electrolyte and carbon powder from electrolytic aluminum anode carbon residues are characterized in that the electrolytic aluminum anode carbon residues are crushed, dried, ground and sieved, fine powder is sent to a cyclone combustion furnace for combustion, the electrolyte in the carbon residues is molten and then enters an electrolyte melting pool, and the surface of the electrolyte melting pool can be subjected to residue stirring; the bottom of the molten pool is poured with a high-temperature-resistant material and is provided with multiple holes, the molten electrolyte flows out of the holes and enters a rotary jet granulation device, the molten electrolyte is cut into frits with small particle sizes under the gas cutting action of rotary jet, meanwhile, the molten electrolyte is cooled by airflow, and the molten electrolyte is separated from the molten pool; the small frits are further cooled, so that the surfaces of the small frits are completely solidified, the small frits are discharged through a discharge port, and flue gas generated by combustion enters a tail flue, exchanges heat with a heat exchanger, enters a dust remover system for dust removal, then enters an alkali liquor spray tower and a denitration device, and is finally emptied; according to the method, the electrolytic aluminum carbon residues are subjected to resource recycling, and the electrolyte utilization rate is increased.

The invention relates to a polymer solid electrolyte, a preparation method thereof and a solid-state battery, the polymer solid electrolyte comprises a polymer, a metal sodium salt and an additive, and the additive is phenylboronic acid functionalized nano silicon dioxide. The invention also provides a solid-state battery comprising the polymer solid-state electrolyte. The MSN-CFPBA is prepared through grafting modification, so that silicon dioxide is functionalized, and the comprehensive performance of the polymer electrolyte is improved. B atoms in a CFBBA molecular structure have Lewis acidity and can be coordinated and interacted with salt anions (such as TFSI-, PF6-and the like), the acting force between the anions and sodium ions is weakened, dissociation and migration of sodium salt are promoted, and meanwhile, the mechanical strength of the electrolyte can be improved and growth of dendritic crystals can be effectively inhibited in the presence of a proper content of nano silicon dioxide. The polymer electrolyte provided by the invention has high ionic conductivity, excellent interface stability and relatively good mechanical property, and is suitable for a high-energy-density solid metal sodium battery.

The invention relates to the field of sodium ion batteries, in particular to a high-rate sodium ion battery and a preparation method thereof. According to the invention, few layers of MXene materials are adopted to manufacture the hard carbon composite material and the special layered structure of MXene, so that the permeation of electrolyte can be effectively improved, the rapid transmission of charges and the diffusion of sodium ions are facilitated, the high rate performance of sodium electricity can be effectively improved, meanwhile, the storage capacity of sodium ions can be improved, and the service life of the sodium electricity is prolonged. The volume change of the hard carbon material in the charging and discharging process is effectively inhibited, and the cycle performance of the battery is favorably improved; the composite glue solution of polyvinylidene fluoride and vinylene carbonate is adopted in the positive electrode slurry, so that the cohesiveness of the positive electrode can be effectively improved, and the composite glue solution is a polymer of a vinylene carbonate additive in the electrolyte, so that the stability between the positive electrode and the electrolyte can be effectively improved.

An electrochemical apparatus is provided and includes an electrode assembly. The electrode assembly includes an electrode plate; the electrode plate includes a current collector; the current collector includes a first region and a second region; an active material layer is arranged on the first region; and a functional layer is arranged on the second region, and the functional layer includes an organic polymer and inorganic particles, where the thickness of the functional layer is H1, where 1 µm ≤ H1 ≤ 15 µm; and Dv90 of the inorganic particles satisfies: 1 µm ≤ Dv90 ≤ 4.5 µm. The electrochemical apparatus in this application has a high electrolyte retention amount, high safety and good cycle performance. Further provided is an electronic apparatus including the electrochemical apparatus.

The invention discloses a composite double-super-ion solid electrolyte and preparation and application thereof, the composite double-super-ion solid electrolyte comprises a polymer matrix, a lithium salt and an inorganic electrolyte filler, the mass ratio of the inorganic electrolyte filler to the polymer matrix is 1: 1-20, and the lithium salt accounts for 1-80 wt% of the total weight of the solid electrolyte. According to the composite double-super-ion solid-state electrolyte, the inorganic electrolyte filler is added and is combined with the polymer matrix, so that the composite double-super-ion solid-state electrolyte integrates the advantages of the polymer solid-state electrolyte and the inorganic solid-state electrolyte, and the inorganic electrolyte filler provides an additional Li < + > transmission path; the conductivity and the lithium ion transference number of the electrolyte are effectively improved, and the solid electrolyte has excellent mechanical properties and is simple to prepare, so that the solid electrolyte has relatively high mechanical strength, electrochemical stability, interfacial compatibility and room-temperature ionic conductivity.

The invention relates to the field of inorganic chemistry, electrochemistry and powder metallurgy science, in particular to a preparation device and a preparation method of metal Ti. The preparation device of the metal Ti comprises the reactor, the anode device and at least one group of cathode devices, preferably, the number of the cathode devices is multiple, so that cathode reactions can be carried out at the same time to improve the yield, different cathodes can also be carried out in turn to carry out the cathode reactions, continuous production is realized, and the production efficiency is improved. According to the preparation method of the metal Ti, the yield and quality of titanium are improved by improving the electrochemical performance of an electrolyte and the mass transfer rate of titanium tetrachloride, molten salt MgCl2 is used as the electrolyte, and the depth of a metal cathode immersed in the molten salt MgCl2 is continuously changed in the reaction process, so that the metal Ti is uniformly deposited on the surface of the metal cathode; and meanwhile, the cathode current density is controlled to be 0.1-10A / cm < 2 >, and the feeding rate of TiCl4 is 130-200g / A.h, so that the yield and the quality of a metallic titanium product are improved.

The invention provides an electrolyte and a secondary battery. The electrolyte comprises an electrolyte salt, an electrolyte additive and the balance of an organic solvent, and the electrolyte additive comprises a first additive and a second additive; wherein the first additive comprises an isocyanate compound, and the second additive comprises a lithium aluminum hydride-based compound and / or an aluminum hydride organic compound. The combination of the first additive and the second additive provided by the invention not only can efficiently remove trace moisture and hydrofluoric acid impurities in the electrolyte and improve the stability of electrolyte salt, but also can improve the film-forming stability and film-forming quality of an SEI (Solid Electrolyte Interphase) film and remarkably improve the cycle performance and high-temperature storage performance of a secondary battery.

The application belongs to the technical field of aluminum smelting, and specifically provides a method for detecting initial crystallization temperature of electrolyte, which comprises the following steps: preparing electrolyte powder from electrolyte to be detected, melting the electrolyte powder to obtain liquid electrolyte; gradually reducing the temperature of the liquid electrolyte, and measuring the viscosity of the liquid electrolyte to obtain the viscosity value of the current temperature every time the temperature is reduced by a preset temperature; drawing a viscosity curve of the liquid electrolyte based on the viscosity values of various temperatures, wherein the viscosity curve is used to represent the relationship between the viscosity of the liquid electrolyte and the temperature; and determining the initial crystallization temperature of the electrolyte to be detected based on the viscosity curve. The technical scheme provided by the application can improve the accuracy of the detection of the initial crystallization temperature of the electrolyte.

The utility model relates to the technical field of electrolyte sampling, in particular to an electrolyte sampling device which comprises a rod, an auxiliary rod and a sampling bottle arranged at the lower end of the main rod, and a bottle opening of the sampling bottle faces upwards; the sampling bottle is provided with a turning cover for controlling opening and closing of a bottle opening of the sampling bottle, the turning cover is rotationally connected with the sampling bottle through a first rotating shaft, the first rotating shaft is arranged in the horizontal direction and is perpendicular to the auxiliary rod, and the lower end of the auxiliary rod is connected to the turning cover and is spaced from the first rotating shaft; the opening of the sampling bottle is provided with a limiting part which protrudes inwards in the radial direction, and when the opening of the sampling bottle is closed by the turning cover, the limiting part abuts against the turning cover upwards or downwards to limit the turning cover. By arranging the turning cover rotationally connected with the sampling bottle and connecting the turning cover to the lower end of the auxiliary rod, a sampler controls the turning cover to rotate forwards and backwards by operating the auxiliary rod, so that opening and closing control of the opening of the sampling bottle is realized, the sampling bottle can extend into a specified depth position for sampling, the electrolyte sampling quality is improved, and the accuracy of a detection result is improved.

The invention discloses a eutectic gel electrolyte and a preparation method and application thereof, and belongs to the technical field of sodium-lithium metal batteries. N-methylacetamide is used as a hydrogen bond acceptor, p-fluorophenylboronic acid is used as a hydrogen bond donor to form a deep eutectic solvent, and a low-volatility system is constructed; the three-dimensional gel network is formed through in-situ cross-linking of the trifunctional acrylate and the difunctional methacrylate, so that electrolyte leakage is inhibited, the thermal stability and intrinsic safety of an electrolyte system are improved, meanwhile, a continuous ion channel is constructed microcosmically, ion conduction and structural stability are both considered, and long-term cycle reliability is guaranteed. While good mechanical strength is maintained, the ionic conductivity of the electrolyte at room temperature reaches about 2.3 mScm <-1 >, which reaches a relatively high level in a gel electrolyte system. The fluoroethylene carbonate film-forming additive is introduced, so that side reaction is effectively inhibited, dendritic crystal growth is inhibited, and the cycle life of the battery is remarkably prolonged.

The invention discloses a cattail wool fiber-based composite diaphragm and a preparation method and application thereof, and belongs to the technical field of battery materials, the preparation method of the cattail wool fiber-based composite diaphragm comprises the following steps: dispersing cattail wool in a sodium hydroxide solution, and performing high-temperature soaking to obtain a first dispersion liquid; filtering the first dispersion liquid, dispersing the filtered first dispersion liquid in a hydrogen peroxide solution, and performing high-temperature soaking to obtain a second dispersion liquid; filtering and drying the second dispersion liquid to obtain cattail fibers; taking cattail wool fibers and qualitative filter paper, and dispersing the cattail wool fibers and the qualitative filter paper into a solvent to obtain a composite suspension; and sieving and drying the composite suspension to obtain the cattail wool fiber-based composite diaphragm. The cattail wool fiber-based composite diaphragm prepared by the method has the comprehensive characteristics of simplicity and convenience in raw material acquisition, low cost, high electrolyte loading rate, high ionic conductivity, good mechanical property, high interface stability and the like, and has excellent cycling stability and high rate capability when being used for a sodium ion battery.

The invention discloses a porphyrin framework polymer as well as a preparation method and application thereof. The porphyrin framework polymer is synthesized by taking tetra (5-bromothienyl) porphyrin as an intermediate, introducing thiophene substituents into four meso sites of porphyrin and then carrying out Stille coupling reaction on the porphyrin and a thiophene tin reagent. The preparation process is mild, purification is simple and convenient, the obtained polymer has high electrolyte solution solubility resistance and excellent electron conductivity, the technical problems that an organic micromolecule active material is prone to dissolution loss in an organic electrolyte, poor in conductivity and the like are effectively solved, and meanwhile the ion transmission capacity of the material is remarkably improved. The porphyrin framework polymer is used as a positive electrode active material and is matched with a metal sodium negative electrode and a NaPF6 carbonate electrolyte to assemble the battery, no obvious capacity fading is caused under 10A g <-1 > large current for about 7000 cycles, the specific capacity is high, the multiplying power and the long cycle performance are excellent, and the porphyrin framework polymer is suitable for a large-scale long-acting energy storage sodium ion battery.

The invention belongs to the technical field of water electrolysis hydrogen production, and particularly relates to a mixed matrix membrane and a preparation method thereof. The preparation method comprises the following steps: adding PMDETA and polybiphenyl isatin into a solvent I for dissolving, and filtering to obtain a clear solution; pouring the clarified solution into a culture dish, and placing the culture dish into a drying oven to volatilize the solvent I to obtain an unmodified mixed matrix membrane; and dipping the unmodified mixed matrix membrane in the oil phase solution, taking out the membrane after dipping, cleaning, and drying to obtain the modified mixed matrix membrane. By adjusting the content of the PMDETA and regulating the reaction sites of the PMDETA and the TBB, the interaction between the membrane and the alkali liquor is enhanced, the wettability between the membrane and the alkali liquor is improved, and absorption and retention of an electrolyte solution are promoted. The modified mixed matrix membrane has relatively high ionic conductivity, relatively high electrolyte uptake rate and relatively low swelling degree, and shows excellent performance in AWE.

The invention discloses a hydrazine gas leakage monitoring device and a monitoring method thereof, and relates to the technical field of hydrazine gas monitoring devices. According to the invention, through cooperation of the display and the alarm, a leakage accident can be timely warned, a real-time state can be displayed, and the capability of leakage detection and early warning is realized; through cooperation of a micro-heating structure and an ultraviolet electrolysis structure, microorganisms are conveniently killed, so that microorganism breeding is avoided, and the capacity of prolonging the service life of the equipment is achieved; finally, the problem that the electrolyte is rapidly disabled due to bacteria breeding in the electrolyte of the existing equipment is solved; after heating is completed, temperature data of the heating wire and the electrolyte are analyzed through the analysis module, the influence of the residual temperature of the heating wire on the temperature of the electrolyte is considered, the heating process of the heating wire is accurately controlled, it is ensured that the temperature of the electrolyte is stabilized at a preset value, and damage to electronic elements caused by too high temperature of the electrolyte is avoided; and accelerated volatilization and decomposition of the electrolyte due to too high temperature are prevented.

The invention provides a cellulose-based sodium ion diaphragm with a double-layer structure and a preparation method of the cellulose-based sodium ion diaphragm, and belongs to the technical field of sodium ion battery diaphragms. According to the diaphragm disclosed by the invention, micron-sized cellulose fibers, nano-sized cellulose fibers, aramid fibrids, aramid chopped fibers and nano Al2O3 are used as main raw materials, and a double-flow-channel synchronous forming process based on a wet-process non-woven fabric process is adopted; and the integrated double-layer composite diaphragm with the rigid corrosion-resistant protective layer facing the positive electrode side and the compact elastic buffer layer facing the negative electrode side is prepared. The diaphragm disclosed by the invention has excellent thermal stability, extremely high electrolyte wettability, good mechanical strength and an adjustable porous structure, the safety performance and the electrochemical performance of the sodium ion battery can be effectively improved, and the preparation process takes water as a medium, is green and environment-friendly and is easy for large-scale production.

The utility model provides equipment for preparing alkali metal salt electrolyte, which comprises a storage tank and a mixing drum, a retainer plate is fixedly connected in the storage tank, a partition plate is arranged above the retainer plate and is used for dividing the storage tank into a plurality of cavities, a plurality of blanking holes are arranged on the retainer plate, a blanking plate is rotatably connected in the storage tank, and the cavity is provided with a plurality of discharge holes. The blanking plate is in sliding fit with the material supporting plate, a discharging hole is formed in the blanking plate, the periphery of the blanking plate is connected with a rotating pushing handle, and the rotating pushing handle is connected to the material storage tank in a sliding mode. According to the equipment for preparing the alkali metal salt electrolyte provided by the utility model, the material storage tank can be divided into a plurality of cavities by the partition plates so as to accommodate different materials, and the blanking plate is driven to rotate by pushing the rotary pushing handle, so that the unloading holes in the blanking plate correspond to the blanking holes in the blanking plate up and down; by means of the discharging mode, the discharging efficiency of the materials is improved, the feeding process is simplified, and the preparation efficiency of the electrolyte is improved.

The low-temperature-resistant electrolyte provided by the invention comprises electrolyte salt, a non-aqueous organic solvent and a low-temperature-resistant additive, and the low-temperature-resistant additive comprises one or more of fluorocarboxylate with a structure shown in a formula I and oxazolidinone compounds with a structure shown in a formula II, the structure of the formula I is # imgabs 0 #, and the structure of the formula II is # imgabs 1 #. The low-temperature-resistant electrolyte provided by the invention solves the problems of high electrolyte viscosity and unstable interface in a battery low-temperature environment, especially the problem that an interface film NaF in a sodium ion battery is easy to decompose, and the low-temperature cycle performance of the battery is improved.

The chemical composition of the solid electrolyte is A (M1bM2cM3dM4e) Fn, A is at least one of Li, Na and K, M1, M2, M3 and M4 are independently selected from one of Ga, Y, In, Mg, Sr, Sc, Al, Fe, Zr, Hf, Ta, Nb, W, Mn, Zn, Co, Mo, Sn, Ca, Pb, Ti, Ru and lanthanide series metal elements, b, c, d and e are molar fractions, b + c + d + e = 1, 0.1 < = b < = 0.3, 0.1 < = d < = 0.3, 0.1 < = e < = 0.3, 0.3 < = c < = 0.5, n = 1 + b epsilon 1 + c epsilon 2 + d epsilon 3 + e epsilon 4, epsilon 1, epsilon 2, epsilon 3 and epsilon 4 are M1, M2 The high-entropy solid solution with an extremely stable structure is formed by utilizing multiple elements, the comprehensive performance is improved through a multi-component synergistic effect, and the performance of the electrolyte is remarkably improved. When the solid electrolyte is applied to the semi-solid lithium metal battery, the rate capability and the cycle performance of the battery can be remarkably improved.

The present invention is directed to agricultural compositions comprising at least one agriculturally active ingredient and gellan gum. The present invention is further directed to tank mixes comprising a high electrolyte composition comprising at least one agriculturally active ingredient and a second composition comprising at least one agriculturally active ingredient, wherein gellan gum is present in the high electrolyte composition or the second composition or is added to the tank mix.

The invention discloses a nitrogen and fluorine modified halide solid electrolyte material as well as a preparation method and application thereof. The structural general formula of the solid electrolyte material is Li < 3x > MN < x > Cl < 5-y > F < y >, wherein M is one or more elements selected from Ta, Nb, Zr, Hf, La and Ce; wherein x is greater than or equal to 0.1 and less than or equal to 0.6, and y is greater than or equal to 0 and less than or equal to 2. Nitrogen ions (N3) and fluorine ions (F) are introduced into a single anion chloride ion (Cl) electrolyte framework for synergistic modification, N3 and M are utilized to form an M-N unit, a local coordination environment is changed to promote amorphous transformation of the electrolyte, and the ionic conductivity is improved. And meanwhile, Cl is partially replaced by virtue of extremely high electronegativity of F, so that the oxidation resistance of the electrolyte is improved, and an electrochemical window is widened. The electrolyte is synthesized by adopting a mechanical ball milling method, the process is simple, the cost is relatively low, and the obtained electrolyte material has excellent interface compatibility and (electro) chemical stability under high voltage.

A preparation method and application of an ionic liquid electrolyte that is resistant to high pressure, highly safe and compatible with ternary high-nickel, low-cobalt positive electrode materials, belongs to the technical field of lithium-ion batteries. The method includes chemically reacting a geminal difluoropyrrole precursor to obtain an ionic liquid, and then sequentially mixing it with lithium salts, carbonates and additives to obtain a non-flammable ionic liquid electrolyte that is compatible with high-pressure environments. This selective introduction of geminal difluoro into the pyrrole molecular skeleton greatly reduces the melting point and viscosity of the ionic liquid; improves the non-flammability of the electrolyte, and avoids the problem of electrolyte corrosion of the current collector. Not only can the advantages of the wide electrochemical window of ionic liquids be brought into play, but geminal difluoro can also improve the compatibility between the electrolyte and the electrode material, solving the problem of poor compatibility between ionic liquid electrolytes and high-nickel, low-cobalt ternary electrode materials. In addition, the ionic liquid electrolyte prepared by the present invention has extremely high cycle stability and excellent capacity retention under high-pressure conditions.

The utility model discloses a vibration cleaning mechanism for electrolyte cleaning, which belongs to the field of electrolyte cleaning and comprises a frame and a steel claw to be cleaned, two symmetrically arranged guide mechanisms are arranged on the frame, each guide mechanism comprises a base, two fixing rods are fixedly connected onto the base, a plurality of guide rods are fixedly connected to the inner sides of the fixing rods, and the guide rods are fixedly connected onto the frame. And a first knocking mechanism is movably arranged on the guide rod. The device has the beneficial effects that the first knocking mechanism and the second knocking mechanism are arranged, simultaneous driving is achieved through the arrangement of the power mechanism, when vibration cleaning is conducted on the to-be-cleaned steel claw, two sets of knocking heads knock and vibrate electrolytes at the first position and the third position, two sets of knocking blocks knock electrolytes at the second position and the fourth position, and staggered knocking facilitates loosening of the electrolytes; and meanwhile, a scraping mechanism is arranged on a mounting seat, so that a scraping plate can perform downward scratching with certain force after hammering of a knocking head, and the electrolyte cleaning effect is further improved.

The application discloses layered accordion structure Bi-MOF and a preparation method and application thereof, and relates to the technical field of electrode materials. The preparation method of the Bi-MOF comprises the following steps: dissolving bismuth nitrate and m-benzenetricarboxylic acid in methanol, and heating to obtain an initial Bi-MOF; and reacting the initial Bi-MOF with a weak base, wherein the weak base comprises at least one of ammonia, hexamethylenetetramine and tetramethylammonium hydroxide, to obtain the Bi-MOF. The Bi-MOF micro-morphology and particle size can be adjusted by adding the weak base, the obtained Bi-MOF sample has variable crystallinity and higher specific surface area, more electrochemical reaction sites can be exposed, the penetration rate of an electrolyte is improved, and the capacitive performance of the Bi-MOF is improved. In the preparation process, no surfactant needs to be added, the consumption of a large amount of water in the washing process is reduced, and the problem of environmental pollution caused by the large emission of the surfactant is solved.

The invention provides an electrolyte, a battery, a battery pack and electric equipment, the electrolyte comprises a solvent, an electrolyte salt and an infiltration additive, the infiltration additive has a special structure, an electrode can have high electrolyte wettability, and the low temperature performance, the rate capability and the cycle performance of the battery are effectively improved.

The utility model discloses a quick stirring device for electrolytic manganese, which relates to the technical field of stirring devices and comprises a stirring tank, a stirring motor is arranged at the top of the stirring tank, and the stirring motor is connected with a stirring paddle; a shaft rod and paddle blades are arranged on the outer side of the stirring paddle; the stirring motor drives the stirring paddle to stir electrolytic manganese, so that manganese ions can be uniformly distributed in the whole electrolyte; through stirring, sufficient manganese ion supply on the surface of the electrode can be ensured all the time, so that a stable electrolytic reaction rate is maintained; the locking sleeve can also drive the cross-shaped rotating frame to rotate, and a plurality of shaft rods and paddle blades arranged on the outer side of the cross-shaped rotating frame can fully stir the electrolyte, so that the stirring range of the electrolyte is widened, and the stirring effect is improved; and the concentration difference between the electrode surface and the electrolyte main body can be effectively reduced, so that the electrolytic reaction is closer to an ideal state. According to the utility model, the problems of uneven quality of the manganese deposition layer caused by local concentration change, such as local looseness, uneven impurity content and the like, can be effectively avoided.

The invention discloses a diaphragm with high electrolyte wettability, a preparation method of the diaphragm and a lithium battery, and relates to the technical field of preparation of battery diaphragms. According to the preparation method, high-temperature-resistant polyether polyol containing a benzene ring reacts with isophorone diisocyanate and citric acid, then 1-allyl cyclohexanol is used for end capping, a modifier containing carboxyl and double bonds is obtained and marked as a double-bond modifier, the double-bond modifier and polyethylene are copolymerized, modified polyethylene is obtained, and the modified polyethylene is prepared. Carboxyl in the double-bond modifier improves the wettability of polyethylene, and meanwhile, a benzene ring endows good high-temperature stability; in addition, the surface of the diaphragm prepared from modified polyethylene is coated with a hydrophilic flame-retardant coating, double bonds in a coating system are initiated by ultraviolet light to polymerize, a hydrophilic flame-retardant layer is formed, the diaphragm is endowed with flame retardance under the condition that the wettability of the diaphragm is not affected, and the safety of the battery is further improved.

This invention discloses a method for preparing a sodium battery composite solid electrolyte, comprising the following steps: S1, preparing a modified solid sodium electrolyte; S2: completely dissolving a polymer in an organic solvent, adding sodium salt and the modified solid sodium electrolyte prepared in S1, stirring to obtain a mixed solution; S3, coating the prepared mixed solution onto the surface of an electrode sheet, and obtaining the sodium battery composite solid electrolyte after drying and hot pressing. The modified solid sodium electrolyte of this invention contains active functional groups such as hydroxyl and amino groups on its surface, which can react with the isocyanate active groups of the polymer solid electrolyte to form urethane and urea covalent bonds, improving the dispersibility of the solid sodium electrolyte in the polymer solid electrolyte. Simultaneously, the composite solid electrolyte forms a cross-linked network structure, reducing the regularity of the polymer molecular chain arrangement, significantly reducing the crystallinity of the polymer solid electrolyte, improving the ionic conductivity of the electrolyte, and also improving the mechanical strength and thermal stability of the composite solid electrolyte.