258results about How to "Reduce polarization" patented technology

The invention provides a positive plate, a preparation method thereof and a battery. The positive plate comprises a positive current collector, and a first positive active coating and a second positive active coating which are sequentially arranged on at least one side of the positive current collector, the first positive electrode active coating is close to one side of the positive electrode current collector, and the first positive electrode active coating comprises a first manganese iron lithium phosphate active material and a nickel-cobalt-manganese ternary active material; in the first positive electrode active coating, the mass ratio of the first lithium manganese iron phosphate active material to the nickel-cobalt-manganese ternary active material is (80-90): (8-15); the second positive electrode active coating is far away from one side of the positive electrode current collector, and the second positive electrode active coating comprises a second lithium manganese iron phosphate active material; the surface density rho1 of the first positive electrode active coating and the surface density rho2 of the second positive electrode active coating meet the following conditions: rho1 is greater than or equal to 240 g / m < 2 >, and rho2 is greater than or equal to 240 g / m < 2 >; and rho1-rho2 is less than or equal to 5g / m < 2 >. The positive plate has relatively high electron conduction and ion conduction performance, meanwhile, the polarization of the positive plate is effectively reduced, and the cycle performance and the thermal stability of the battery are greatly improved.

The invention provides a thick electrode and a preparation method thereof, and a lithium battery, the thick electrode comprises a current collector and an active coating, the active coating comprises an active material, a conductive agent, a dispersant and a composite binder, the composite binder comprises a binder A and a binder B, the binder A comprises at least two of sodium carboxymethyl cellulose, a polyacrylic acid binder and an acrylonitrile multipolymer, and the binder B comprises at least one of polytetrafluoroethylene and butadiene styrene rubber. The thick electrode has the characteristics of stable structure, good conductivity and high ion transmission efficiency, and the cycling stability of the battery using the thick electrode can be improved.

The invention discloses a chromium group metal doped platinum alloy catalyst as well as a preparation method and application thereof, and relates to a platinum alloy catalyst as well as a preparation method and application thereof. The technical problem that an existing alloy catalyst formed by Pt and transition metal is poor in catalytic activity and durability is solved. According to the catalyst, PtM alloy nano-particles doped with a chromium group element X are uniformly supported on a carbon carrier; in the PtM alloy doped with the chromium group element X, X exists in the form of a simple substance, and the mass percentage content of X is 5%-10%; the X-PtM / C is marked as X-PtM / C, and X is Cr, Mo or W; m is Fe, Co or Ni. The preparation method comprises the following steps: carrying out secondary reduction and high-temperature heat treatment by taking Pt / C as a precursor to obtain the catalyst. The mass activities of Cr-PtNi / C, Mo-PtNi / C and Cr-PtCo / C are respectively 0.419 A / mgPt, 0.254 A / mgPt and 0.314 A / mgPt, and are 5.0 to 8.1 times of that of Pt / C. And after the Cr-PtNi / C is aged for 30000 circles, the potential is not attenuated. The invention can be used in fuel cell field.

The present invention discloses a method for preparing a lithium battery high energy density and fast charging graphite negative electrode material, comprising the following steps: mixing, briquetting, and graphitization. The modified graphene is evenly distributed in the graphite phase, and the two have good contact performance, which greatly enhances the conductivity of the graphite material and its coating layer. The amount of conductive agent added can be reduced in the manufacturing process, so that more active substances can be placed in a limited battery space, increasing the energy density of the battery; secondly, catalytic graphitization can increase the capacity of graphite to more than 360 mAh / g, further improving the energy density of the battery; the synergistic effect brought about by graphene modification and catalyst pore formation improves the fast charging performance, and graphene forms a rich conductive network between graphite and granulated coating layers, reducing system impedance and battery polarization, improving conductivity, and enhancing the rate characteristics of the battery. The catalyst volatilization will leave abundant pores, providing a convenient path for the diffusion of lithium ions, and improving the fast charging performance.

The utility model discloses a flotation machine scraper cleaning device which comprises a mounting plate, a rotating shaft is rotatably connected to the interior of the mounting plate, a rotating roller is fixedly installed at the end of the rotating shaft, when a scraper in a flotation machine needs to be cleaned, the rotating shaft rotates and drives the rotating roller to rotate along with the rotating shaft, and under the action of centrifugal force, the scraper in the flotation machine is cleaned. A limiting groove formed in the outer wall of the scraping plate slides on the outer wall of a limiting block fixedly installed on the inner side of the sliding frame, an I-shaped balancing weight slides in the sleeve frame under the action of centrifugal force and gravity and pushes a limiting plate, the limiting plate and the scraping plate are thrown out of the sleeve frame, the scraping plate can conduct flotation work at the moment, and along with rotation of the scraping plate, the sleeve frame is far away from a flotation tank; at the moment, the I-shaped balancing weight slides towards the interior of the sleeve frame, the limiting plate is driven to slide along with the I-shaped balancing weight, the scraping plate slidably arranged on the inner side of the limiting plate slides towards the interior of the sleeve frame along with the limiting plate, the outer wall of the scraping plate makes contact with the scraping frame arranged on the outer wall of the sleeve frame, and impurities attached to the outer wall of the scraping plate are scraped and cleaned under the limitation of the scraping frame.

The invention provides a quick-charge and quick-discharge type lithium battery and a preparation method thereof, and belongs to the technical field of lithium battery preparation. The preparation process comprises the following steps: preparing a fluorinated carbon nanotube based on biomass carbon; preparing a positive electrode plate; preparing the dendritic mesoporous silicon dioxide nano particles; preparing a cerium oxide-loaded two-dimensional hierarchical porous composite material; preparing a negative electrode plate; and assembling the lithium battery. According to the preparation method, the eutectic and the carbon fluoride nanotubes are added in the preparation of the positive electrode plate, and the cerium oxide-loaded two-dimensional hierarchical porous composite material and the carbon fluoride nanotubes are added in the preparation of the negative electrode plate, so that the prepared positive electrode plate and the prepared negative electrode plate have relatively high conductivity; and moreover, the ion transmission efficiency is improved, the rapid ion transmission is beneficial to reducing the polarization phenomenon of the battery, improving the charging and discharging rate and the power performance of the battery, enhancing the structural stability of the electrode, improving the performance and the safety of the battery, and being more beneficial to rapid charging and rapid discharging.

The invention belongs to the technical field of lithium ion battery positive electrode materials, and provides a high-specific-energy lithium manganese iron phosphate positive electrode material and a preparation method thereof.The preparation method comprises the following steps that 1, carbon nanotubes are added into deionized water to be subjected to ultrasonic dispersion, modified xanthan gum, ammonia water and hydrazine hydrate are added to be stirred, the mixture is heated to continue to be stirred, suction filtration and washing are conducted, and carbon nanotubes are obtained; drying to obtain a carbon source; step 2, adding the lithium hydroxide solution into the phosphoric acid solution, stirring and dispersing, adjusting the pH value, adding the manganese sulfate solution and the ferrous sulfate solution, and carrying out hydrothermal synthesis reaction to obtain a hydrothermal reaction product; step 3, centrifuging, washing and drying the hydrothermal reaction product, and mixing the dried product with a carbon source to obtain a mixture; step 4, carrying out ball milling on the mixture to obtain powder; and step 5, calcining the powder, and cooling to obtain the product. The obtained lithium manganese iron phosphate positive electrode material has the advantages of uniform thickness of a carbon coating layer, excellent electrochemical performance, stable cycle performance and the like.

The invention relates to a transmission grating and a preparation method thereof, and the transmission grating comprises a substrate which is provided with a first surface; the grating layer comprises trapezoidal grating teeth arranged on the first surface in an array mode, the grating teeth extend in the thickness direction of the substrate, and a gap is formed between every two adjacent grating teeth; the dielectric layer is arranged on the surface of the grating layer and fills the gap, one side, far away from the substrate, of the dielectric layer is provided with a second surface, a difference value exists between the distance between the second surface and the first surface and the height of the grating teeth, and the difference value is m; incident light enters the second surface through the inside of the grating layer. By designing the film layer structure and the film layer size of the transmission grating, the transmission grating with different diffraction efficiencies and polarization degrees can be obtained, the size of the film layer structure of the transmission grating can be accurately controlled during processing, and processing is easy.

The invention provides a flexible ionic polymer binder as well as a preparation method and application thereof, and belongs to the technical field of lithium ion batteries. The invention provides a flexible ionic polymer binder, which has a chemical structure as shown in a formula I. When the binder is used for a positive electrode of a lithium ion battery, a polyacrylic acid trialkyl amino ester anionic salt chain segment provides an active site, and chemical bonds or electrostatic interaction is generated between the binder and a positive electrode active material, so that the positive electrode active material is formed. The specific type of anions improves the interaction between the binder and the positive electrode active material, and improves the capacity and cycle performance of the battery. The result of the embodiment shows that the initial specific discharge capacity of a lithium ion battery assembled by a positive pole piece prepared from the flexible ionic polymer binder provided by the invention can reach 155.2 mAh / g, the initial specific discharge capacity can still be kept at 149.9 mAh / g after 800 cycles under the current density of 0.5 C, the capacity retention rate can reach 96.59%, and the lithium ion battery has good cycle performance.

The invention discloses zinc ion battery electrolyte as well as a preparation method and application thereof, and belongs to the technical field of ion battery electrolyte. According to the preparation method disclosed by the invention, the coumarin derivative is added into the basic zinc salt solution, so that the uniform deposition of zinc ions can be promoted at a low temperature of-20 DEG C or below, the formation of dendritic crystals is remarkably reduced, and a stable protective layer is formed on the surface of the zinc anode, and the protective layer can maintain high reversibility of the battery at a normal temperature, and also can be used for preparing a lithium ion battery. And the stability can be kept in a low-temperature environment, so that the battery can show excellent electrochemical performance under different temperature conditions, and the technical problem of the electrochemical performance of the water-based zinc ion battery (ZIBs) in the low-temperature environment is solved.

The invention relates to the technical field of preparation of lithium iron phosphate positive electrode materials, and discloses a method for preparing modified lithium iron phosphate through carbon-coated metal doping and positive electrode lithium supplementation, which comprises the following steps: S1, dissolving Li3PO4 powder, adding a Fe2SO. 7H2O aqueous solution into the solution, stirring and drying to obtain a LiFePO4 precursor; s2, testing the element content of the precursor; s3, supplementing a lithium source and a phosphorus source to the precursor, adding a carbon source and metal salt, and uniformly mixing; s4, the precursor mixed solution is put into a sand mill to be subjected to sand milling for 60-120 min to be fully mixed; s5, performing spray drying on the sanded precursor, and collecting a product; and S6, calcining and carbonizing the product to obtain the active substance. S7, dissolving the active substance, and magnetically stirring and mixing; and S8, performing coating and vacuum drying on the mixed slurry, and performing half-cell manufacturing and electrochemical performance testing. The crystal stability is improved, and the battery life is prolonged.

The invention provides a preparation method of an HNT modified polymer composite membrane. The preparation method comprises the following steps: S1, preparing dealuminated HNT; s2, preparing modified HNT by using the dealuminated HNT; s3, preparing sulfonated polyether ether ketone; s4, performing ionization treatment on the sulfonated polyether ether ketone; and S5, preparing the HNT modified polymer composite membrane by using the modified HNT and the sulfonated polyetheretherketone or perfluorosulfonic acid membrane obtained in the step S4. The problems that an existing flow battery diaphragm is poor in comprehensive performance, high in cost and not suitable for various systems are solved.

The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery diaphragm containing modified halloysite nanotubes, a preparation method of the lithium ion battery diaphragm and a lithium ion battery, and the preparation method comprises four steps which are shown in Figure 1 in Figure 1 in Figure 1 in the specification. According to the invention, the sulfonated lithiated halloysite nanotube (sHNT-Li) is introduced into the battery diaphragm, so that the affinity between the diaphragm and an electrolyte is increased, and more sites and channels are provided for lithium ion transmission; and sHNT-Li is utilized to change the diffusion force in the process of a non-solvent phase conversion method, so that the high-temperature-resistant lithium ion battery diaphragm with a microscopic pore channel structure consisting of regular finger-shaped pores and spongy pores is obtained. The diaphragm electrolyte is good in wettability, high in conductivity, good in electrochemical stability and good in lithium dendrite inhibition effect. The battery assembled by the diaphragm shows excellent specific discharge capacity, cycling stability and rate capability, and especially has excellent charge-discharge stability at high temperature; in addition, the electrode polarization degree of the battery is improved.

The invention relates to the technical field of silicon-based anode materials, in particular to a method for reducing structural deformation and damage in the circulation process of a silicon-based anode. The preparation method comprises the following steps: adopting Ti < 3 > C < 2 > T < x > MXeneamp; the SGC composite material is used as a silicon-based anode active material; the Ti < 3 > C < 2 > T < x > M < X > eneamp; the preparation method of the SGC composite material comprises the following steps: (1) dispersing nano silicon into phenolic resin, then enabling the nano silicon and graphene oxide to be adsorbed and self-assembled to form gel by utilizing a surface charge adsorption effect, and then performing freeze drying, grinding, carbonization treatment and CVD treatment to obtain the SGC composite material; (2) the surface of the SGC composite material is coated with the Ti < 3 > C < 2 > T < x > MXene nanosheets in a vacuum suction filtration mode, and Ti < 3 > C < 2 > T < x > MXene amp is obtained; the invention discloses an SGC composite material.

The invention relates to a silicon-carbon composite material, a preparation method and application thereof, and a battery. The silicon-carbon composite material comprises: a porous carbon matrix; the metal coating is positioned on the hole wall of the porous carbon substrate; the silicon alloy particles are positioned on the surface of the metal coating; the amorphous silicon particles grow along the epitaxy of the silicon alloy particles; and a carbon coating layer, wherein the carbon coating layer is located at the outer layer. The silicon-carbon composite material disclosed by the invention has excellent conductivity and structural stability, and the battery adopting the silicon-carbon composite material can realize high mass specific capacity and excellent high-temperature and low-temperature cycling stability.

The invention relates to an integrated negative electrode binder for a silicon-based negative electrode, a negative electrode plate and a lithium battery. Wherein the integrated negative electrode binder for the silicon-based negative electrode comprises a polymer and a conductive material; the polymer comprises a polyacrylic acid copolymer modified by a hydrophilic block and a hydrophobic block, the weight-average molecular weight of the polymer is 600,000-800,000, the number-average molecular weight of the polymer is 300,000-500,000, and the polydispersity of the polymer is 1.2-2.5. The silicon negative electrode has the advantages that the mechanical performance of the silicon negative electrode can be improved, the stress generated in the volume expansion of the silicon particles is dissipated, so that the silicon particles are prevented from being broken, and the adhesion to the conductive carbon material is good.

The invention belongs to the technical field of solid-state lithium metal batteries, and discloses an amorphous inorganic ion conductor and a preparation method and application thereof, and the preparation method comprises the following steps: uniformly mixing lithium tetrachloroaluminate and sodium tetrachloroaluminate to obtain a mixture; and melting the mixture to obtain a molten precursor, and cooling the molten precursor to room temperature to obtain the amorphous inorganic lithium ion conductor Li < x > Na < 1-x > AlCl4, x being greater than or equal to 0.15 and less than or equal to 0.85, wherein the amorphous inorganic lithium ion conductor Li < x > Na < 1-x > AlCl4 is used as an interface phase between a positive electrode of a solid-state lithium metal battery and a solid-state electrolyte. The amorphous LixNa1-xAlCl4 has the remarkable advantages that the preparation temperature is low, the crystal structure of the product can be controlled, the ionic conductivity of the product is high, and the compatibility with a solid electrolyte and a positive electrode material is good. The method is short in preparation period, low in cost and suitable for industrial application.

The invention relates to an asphalt-based silicon-carbon composite material, a preparation method thereof and a lithium ion battery. The preparation method comprises the following steps: providing pitch coke, sodium hydroxide and lithium carbonate, uniformly mixing the raw materials, calcining in a nitrogen atmosphere, sequentially washing with mixed acid and deionized water after calcining, and carrying out vacuum drying to obtain pitch-based porous carbon; adding the pitch-based porous carbon into a vacuum furnace, and respectively introducing heteroatom gas, silane gas and metal compound gas in stages to obtain a metal-doped silicon-carbon precursor material; and heating the metal-doped silicon-carbon precursor material, introducing oxidizing mixed gas for passivation, soaking the passivated metal-doped silicon-carbon precursor material in an organic solvent of an organic lithium compound, uniformly mixing, and carrying out spray drying to realize secondary coating, thereby obtaining the asphalt-based silicon-carbon composite material. The asphalt-based silicon-carbon composite material has a three-layer core-shell structure, so that the stability and the performance of the material are improved, and the first efficiency and the power performance of the material can be improved.

The invention provides a cellulose composite carbon aerogel and a preparation method thereof, and the cellulose composite carbon aerogel is prepared by taking cellulose nanofibers and carbon nanotubes as raw materials, mixing and dispersing the raw materials through dispersoid, and then preparing cellulose nanofiber / carbon nanotube composite carbon aerogel through bidirectional freezing, freeze drying and high-temperature carbonization. The invention also provides an application of the cellulose composite carbon aerogel in the aspect of a battery electrode, and the cellulose composite carbon aerogel has an ultra-large specific surface area and an excellent compression ratio under ultra-low density, and shows super-hydrophilicity, high electrochemical activity, good compression resilience, good structural stability and certain mechanical strength; and the method can be used for various electrochemistry-based water-based flow batteries. The invention solves the technical problem that the existing cellulose carbon aerogel is poor in compressibility and mechanical strength, and belongs to the technical field of batteries.

The invention relates to the technical field of polaroids, and discloses a preparation method of a dye-based high-durability OLED (Organic Light Emitting Diode) polaroid for vehicle-mounted display, and the preparation process comprises the following steps: putting a PVA (Polyvinyl Alcohol) film into a swelling tank containing 1.0 wt%-2.5 wt% of boric acid for swelling pretreatment; dip dyeing: soaking the PVA film subjected to dip dyeing treatment in a solution tank containing boric acid, and stretching the PVA film; the concentration of boric acid is 1wt%-6wt%, drying, curing the original plate, gluing, coating a pressure-sensitive adhesive on the dye polarized original plate, and then compounding the compensation film A, the compensation film B and the like. The dye-series high-durability OLED polaroid prepared by the invention has a thinned structure and excellent weather resistance, and after a 105 DEG C * 1000h dry temperature test, a 85 DEG C * 85% RH * 1000h high-temperature and high-humidity test and a weather resistance test are met, the optical performance change rate of the polaroid is less than or equal to 5%, and the product is free from depolarization and layering.

The invention relates to the technical field of batteries, in particular to a positive electrode material and a preparation method thereof, a positive plate and a sodium ion battery. The positive electrode material comprises: a) a base material having a chemical formula of Na < 3 + x + y > V < 2-x-y > CoxCuy (PO4) 3, 0.01 < = x < = 0.12, 0.01 < = y < = 0.12, and 0.02 < = x + y < = 0.2; b) a metal oxide anchored to a portion of the surface of the matrix material; and c) a carbon coating layer arranged on at least part of the surface of the matrix material anchored with the metal oxide. After Co < 2 + > and Cu < 2 + > double-element doping, lattice distortion can be formed in the material, an ion transmission channel is widened, the diffusion resistance of Na < + > in the material is reduced, and diffusion kinetics is improved.

The invention relates to the technical field of batteries, in particular to an electrode plate, a preparation method thereof and a battery. The electrode plate comprises a current collector; the electrode material layer is arranged on at least one side surface of the current collector along the thickness direction; the middle transition layer is arranged on the surface, away from the current collector, of the electrode material layer, and each of the electrode material layer and the middle transition layer comprises an active material and a composite solid electrolyte; the solid electrolyte layer is arranged on the surface, far away from the electrode material layer, of the middle transition layer, and the solid electrolyte layer comprises a composite solid electrolyte; the composite solid-state electrolyte comprises an inorganic solid-state electrolyte and an organic solid-state electrolyte with lithium-conducting and electric-conducting capabilities; and the content of the composite solid electrolyte in the middle transition layer is greater than the content of the composite solid electrolyte in the electrode material layer. The battery comprises the provided electrode pole piece. According to the invention, the migration dynamics performance of lithium ions can be improved, the conductivity and compaction density of the pole piece are improved, and the cycle performance and safety performance of the battery are improved.

The invention discloses a high-conductivity sodium ion battery positive electrode material / organic conductive polymer composite material and a preparation method thereof, and the preparation method comprises the following steps: S1, preparation of a chain product: adding water into an organic conductive polymer monomer for dissolving, adjusting the pH value of the solution to be acidic, adding an oxidizing agent, and stirring to obtain the chain product; inducing an organic conductive polymer monomer to generate a polymerization reaction to form a chain product; s2, preparation of precursor slurry: adding a sodium source, an iron source and a sulfur source into the solution for forming the chain product, and fully dissolving to form uniform precursor slurry; s3, preparation of precursor powder: drying the precursor slurry to realize solid-liquid separation so as to obtain dried precursor powder; and S4, high-temperature sintering: calcining the precursor powder in a protective atmosphere, and naturally cooling to obtain the Na < 2 + x > Fe < 2-x > (SO4) 3 / organic conductive polymer composite positive electrode material. The preparation method has the characteristics of high electronic conductivity, low specific surface area, high compaction density and excellent electrochemical performance.

The invention belongs to the field of solid electrolytes, and particularly relates to a preparation method of a cross-linked polyether-based solid electrolyte, which comprises the following steps: polymerizing a precursor solution containing an ether monomer, a cross-linking agent containing an epoxy group, an electrolyte salt, an auxiliary agent I and an auxiliary agent II under ultraviolet irradiation to obtain the cross-linked polyether-based solid electrolyte, the auxiliary agent I is a compound which contains a structure shown in a formula 1 # imgabs0 # and can release free radicals under ultraviolet light; the auxiliary agent II is at least one cationic organic matter of diazonium salt, iodonium salt, sulfonium salt, ferrocene salt, sulfonyloxy ketone and triaryl siloxy ether. The invention also discloses the material prepared by the preparation method and an application of the material in a battery. According to the invention, the cyclic ether monomer, the cross-linking agent, the assistant I and the assistant II are polymerized under ultraviolet light, so that the polymerization of the cyclic ether monomer can be realized based on a brand new photo-initiation mechanism, and furthermore, the polymerization behavior and uniformity can be optimized, so that the comprehensive properties such as stability, mechanical property, conductivity and the like of the prepared solid electrolyte are improved.

The invention discloses a modified MOFs filler, a preparation method and a composite solid electrolyte of a lithium ion battery, and the preparation method of the modified MOFs filler comprises the following steps: adding cerium salt during preparation of an MOF material to obtain a cerium-doped MOF material; or after the MOF material is prepared, the MOF material is etched, and the etched MOF material is obtained. The preparation method of the composite solid electrolyte comprises the following steps: dispersing the prepared MOF material in a solvent under the protection of inert gas, adding an electrolyte lithium salt and PEO, stirring to obtain a colloidal suspension, pouring the colloidal suspension into a mold, and drying and molding. After the obtained modified MOFs filler is added into the composite solid electrolyte, the conductivity of the composite solid electrolyte can be effectively improved, the composite solid electrolyte has a wide electrochemical stability window, and an assembled lithium ion battery shows excellent electrochemical performance.

In order to solve the problem that high-rate discharge performance and high-temperature cycle performance of a lithium ion battery in a low-temperature environment are difficult to consider in the prior art, the invention provides a lithium ion battery which comprises a positive plate, a negative plate and an electrolyte, the positive plate comprises a positive electrode material layer, and the positive electrode material layer comprises a positive electrode active material and a solid electrolyte; the electrolyte comprises a first additive; the first additive comprises at least one of the following compounds: # imgabs0 #; the lithium ion battery satisfies the following conditions: 1.25 < = L / (D * S) < = 5; s% is the mass percentage content of the first additive in the electrolyte; l% is the mass percentage content of the solid electrolyte in the positive electrode material layer; and D [mu] m is the median particle diameter D50 of the solid electrolyte in the positive electrode material layer. According to the lithium ion battery provided by the invention, by adding the solid electrolyte and the first additive and adjusting the relationship among the first additive, the solid electrolyte and the median particle size D50 of the solid electrolyte in the positive electrode material layer, the high-rate discharge and high-temperature cycle performance of the lithium ion battery in a low-temperature environment is improved.

The invention belongs to the field of sodium-ion batteries, and discloses a high-voltage-resistant sodium-ion battery positive electrode material which comprises a core layer and a coating layer, the chemical formula of the core layer is Na < x > Ca < y > (NiFeMn) < 0.33 > x (1-z-e) Al < z > Mg < e > O < 2 >; the chemical formula of the coating layer is Na3La2 (BO3) 3. (AFm) n; 0.99 < = x + y < = 1.04, 0.01 < = y < = 0.05, 0.01 < = z < = 0.1, 0 < = n < = 0.05, 0.0023 < = e < = 0.023; a is Ca and / or Al, and m is the valence state of the A element. According to the positive electrode material, through doping and coating of the core layer, the stability of the core layer material, the coating material and the interface stability of the core layer material and the coating material are realized, particularly, the surface stability of the doped core layer is remarkably improved, and the capacity and the cycle performance under the condition of high voltage are improved. Meanwhile, the invention also provides a preparation method of the high-voltage-resistant sodium-ion battery positive electrode material.

The invention provides a positive plate, a battery cell and a battery. The positive plate comprises a current collector; the current collector comprises a first surface and a second surface which are opposite in the thickness direction; the coating comprises a safety coating and an active substance layer, the safety coating is located on the surface of the current collector, and the active substance layer is located on the surface, away from the current collector, of the safety coating; the positive plate is provided with a first area, and the first surface and the second surface of a current collector in the first area are provided with a safety coating and an active material layer; a plurality of first protrusions and first recesses corresponding to the first protrusions are arranged in the first area, and the first protrusions are formed by protruding the safety coating and the active material layer on the first surface towards the second surface. The safety coating forms a convex part and a concave part which are matched with the first bulge and the first recess; the safety coating further comprises a straight part located outside the protruding part, and the thickness of the vertex area of the protruding part of the safety coating is smaller than that of the straight part of the safety coating. According to the positive plate, impedance can be reduced, and polarization can be weakened.

The invention discloses a method for improving alkaline water electrolysis hydrogen production efficiency by using electrolyte concentration difference, and belongs to the technical field of water electrolysis hydrogen production. The method comprises the following steps: adding KOH electrolyte with the concentration of 30wt% into the cathode region on one side of the diaphragm, and adding KOH electrolyte with the concentration of 35wt% into the anode region on the other side of the diaphragm; and electrifying the electrolytic bath, controlling the temperature to be 80-90 DEG C, and carrying out electrolytic reaction on the water under the action of the electric field. The hydrogen production efficiency of alkaline electrolyzed water is improved by utilizing the electrolyte concentration difference, the hydrogen production efficiency and the hydrogen purity can be improved, the energy consumption and the equipment cost can be reduced, the reliability and the durability of the system are improved, meanwhile, the environmental influence is reduced, and a positive role is played in promoting the production and the application of green hydrogen.

The invention relates to an ultra-wideband flexible transparent ultra-thin metamaterial wave absorber, which solves the problems of low profile, wide bandwidth and insensitive polarization and angle of the wave absorber, and belongs to the field of electromagnetic metamaterials. The antenna comprises a first dielectric layer, a second dielectric layer and a third dielectric layer which are sequentially arranged from bottom to top, the first dielectric layer and the third dielectric layer are PET substrates; the second dielectric layer is a PVC layer; the upper surface of the third dielectric layer is provided with conductive film units which are arranged periodically, and the lower surface of the first dielectric layer is covered with a conductive film. The upper surface of the third dielectric layer is provided with four conductive thin film units which are periodically arranged, and each conductive thin film unit is an ITO resistive thin film with a cross-shaped pattern. According to the invention, the flexible PVC is used as the dielectric substrate, the PET is used as the reflection bottom plate and the resonance layer, and the conductive film pattern of the resonance layer is optimally designed, so that the absorption performance of which the absorption rate is greater than 90% is realized within the frequency range of 12.02-102.91 GHz, and the relative absorption bandwidth can reach 158.1%.