102results about How to "Improve energy storage characteristics" patented technology

The invention discloses a preparation method of a high-specific-surface-area porous nitrogen-doped graphitizing carbon nanomaterial, relating to a preparation method of a carbon material and aiming at solving the problems of small specific surface area, low nitrogen content, low productivity, poor graphitizing degree and high cost of the nitrogen-doped graphitizing carbon nanomaterial prepared by the prior art. The preparation method comprises the steps of: I. preparing a complex; II. curing and carbonizing the complex; and III. carrying out acid leaching method treatment, and drying. Compared with an existing nitrogen-doped graphitizing carbon nanomaterial, the prepared high-specific-surface-area porous nitrogen-doped graphitizing carbon nanomaterial has the advantages that the graphitizing degree is improved, the nitrogen content is increased, and the specific surface area is obviously increased, and the high-specific-surface-area porous nitrogen-doped graphitizing carbon nanomaterial has obvious pore diameter distribution. The preparation method is used for preparing the high-specific-surface-area porous nitrogen-doped graphitizing carbon nanomaterial.

The invention relates to the field of chemical energy storage devices such as super capacitors, batteries and the like, and particularly discloses a composite material based on nanometer, a preparation method of the composite material and application in a flexible energy storage device, which solve the problem that common energy storage devices are difficult to be bent and deform. Nanometer active materials are compounded with flexible fibers, high-energy-storage characteristics of the nanometer active materials and excellent flexibility of flexible fiber materials are integrated, the quality percentage of the nanometer active materials ranges from 0.1% to 40%, the rest components of the composite material are the flexible fibers, the flexible nanometer composite material in a three-dimensional communication network structure is formed, furthermore, the composite material can be used as an electrode active material and a current collector simultaneously so as to be assembled to form the bendable flexible energy storage device, higher specific capacity can be realized under a bending condition and is equivalent to that when the flexible energy storage device is not bent, and the composite material can be expected to be applied to the field of flexible devices in the future.

The invention discloses a high-energy-storage sodium bismuth titanate-strontium titanate matrix material. The chemical formula of the high-energy-storage sodium bismuth titanate-strontium titanate matrix material is 0.5Bi0.5Na0.5TiO3-0.5SrTiO3-x wt%MgO, wherein x=0.5-3.0. A preparation method of the high-energy-storage sodium bismuth titanate-strontium titanate matrix material comprises the following steps of preparing SrCO3, TiO2, Bi2O3, Na2CO3 and MgO by weight ratio according to the chemical formula into a ceramic powder, performing ball milling, drying and pelletizing, and then pressing the ceramic powder in a tablet press into a ceramic blank; rubber-discharging and sintering the ceramic blank inside a muffle furnace to obtain a ceramic sample. The preparation method of the high-energy-storage sodium bismuth titanate-strontium titanate matrix material is simple in preparation process, low in cost and free from pollution; the prepared high-energy-storage sodium bismuth titanate-strontium titanate matrix material achieves a high discharging energy storage density of 1.61-2.17 J / cm3 and a high breakdown strength of 137-226 KV / cm.

The invention relates to a Ni-Mn-Zn ferrite and the preparation method, in particular to a high saturation magnetic flux density low Ni-Mn-Zn power loss ferrite and the preparation method. The main technical proposal of the invention is: the ferrite comprises components with the following molar percentage: Fe2O3:53 to 55mol%, MnO:35 to 37mol%, ZnO:5 to 8mol%, NiO:2 to 4mol%. The invention has an advantage of providing a high saturation magnetic flux density low Ni-Mn-Zn power loss ferrite with reasonable design, high saturation magnetic flux density, high frequency and low power loss.

The invention belongs to the field of a compound medium and particularly relates to a nanofiber / PVDF (polyvinylidene fluoride) compound medium with a sandwich structure and a preparation method of the nanofiber / PVDF compound medium. Upper and lower layers of the sandwich structure of the compound medium are PVDF films, a middle layer is a CFO@BZT-BCT NFs / PVDF compound medium film, and the three layers of structure media are combined through hot pressing, wherein the PVDF films are prepared with a solution tape casting method through quenching treatment, and the CFO@BZT-BCT NFs / PVDF compound medium film is prepared through steps as follows: crystalized BZT-BCT NFs is prepared from a BZT-BCT spinning precursor through electrostatic spinning and high-temperature calcination, CFO is introduced, CFO@BZT-BCT NFs is prepared and subjected to surface modification with dopamine hydrochloride, finally, CFO@BZT-BCT NFs is mixed with PVDF, suspension turbid colloid is prepared and subjected to solution tape casting and quenching treatment, and the nanofiber / PVDF compound medium is prepared. The technical problems of low energy density and high dielectric loss of an inorganic filling phase / polymer based compound medium are solved.

The invention discloses a method for preparing nano trimanganese tetroxide. The method is characterized by comprising the steps of by selecting waste banana peels as a raw material, drying in air, cutting into small pieces, heating with water, extracting active ingredients, reacting with potassium permanganate, filtering, and drying to obtain the nano trimanganese tetroxide which has the particle size of 10-80 nanometers, has good capacitance property and high energy storage property and serves as an electrode material for supercapacitors. Compared with the prior art, the method has the advantages that the preparation process is simple, low in cost, environmental friendly and rich in resource, and the product has the application advantage and has good economic, social and ecological benefits.

The invention discloses an electric automobile power supply free of external charging. The electric automobile power supply comprises an energy storage cell which is used for charging a power cell or directly driving a motor, an energy storage cell control unit which is used for controlling the energy storage cell and adjusting the start and stop and the output power of the energy storage cell by controlling the gas, water and heat inside the energy storage cell, the power cell which is used for directly providing electric energy for the motor and maintaining the normal rotating power of the motor in an electric automobile through receiving the electric energy which is provided by the energy storage cell, a power cell management unit which is used for controlling the discharging and the charging of the power cell, a DC (Direct Current) / DC (Direct Current) converting unit which is used for converting the direct current voltage which is fluctuant in a fixed range into the voltage which can be loaded on the power cell, and a power system control unit which is used for adjusting the power generation of the energy storage cell and the charging and discharging of the power cell, and providing the electric energy for the motor. According to the electric automobile power supply free of external charging, a fuel cell is used as the energy storage cell and used for assisting electricity supply, the real-time charging of the electric automobile is realized, and an external charging interface is not needed.

The invention relates to a strontium titanate-based lead-free high-energy storage density and high-energy storage efficiency ceramic material and a preparation method thereof. The preparation method comprises the following steps: firstly batching according to a chemical formula (1-x)SrTiO3-x(0.65BaTiO3-0.35Bi0.5Na0.5TiO3), wherein x represents a molar fraction and is greater than or equal to 0.1 but less than or equal to 0.6; ball-milling and drying to obtain a raw material powder body; adding the obtained raw material powder body into a bonding agent for pelleting, decaying for 24-48 hours, pressing into a sheet, performing glue removal treatment and sintering at a temperature of 1250-1350 DEG C to obtain the strontium titanate-based lead-free high-energy storage density and high-energy storage efficiency ceramic material. The ceramic material provided by the invention is simple and stable in preparation process, suitable for industrial production and excellent in energy storage characteristics, the energy storage density calculated based on a ferroelectric hysteresis loop is 0.961-1.403 J / cm<3>, and the energy storage efficiency is 84.77-91.63 percent.

The invention discloses a manganese dioxide film electrode with double 3-dimensional (3D) structures for a super capacitor and a preparation method thereof. The manganese dioxide film electrode is formed by covering a manganese dioxide film in the 3D structure on a current collector of foam metals such as foam nickel and the like in the 3D structure. The preparation method comprises the step thatthe reaction is directly carried out on the current collector of foam metals such as foam nickel and the like through a hydro-thermal method for preparing the manganese dioxide film. The hydro-thermal preparation process comprises steps of current collector cleaning, solution preparation, hydro-thermal reaction and the like. The prepared manganese dioxide film electrode has double 3D structures and has good capacitance characteristics and higher energy storage characteristics when being used as an electrode of the super capacitor. Compared with the prior art, the prepared manganese dioxide film electrode for the super capacitor has larger contact area of active substance and electrolyte than that of the existing manganese dioxide electrode, and higher active substance utilization rate andhigher specific capacity are realized.

The invention relates to a high-energy-storage barium titanate dielectric material and a preparation method thereof. The high-energy-storage barium titanate dielectric material has a chemical formulaof (1-x)BaTiO3-xBi(Mg1 / 2Zr1 / 2)O3, wherein x=0.02-0.20. The preparation method includes the steps of (1) preparing BaCO3, TiO2, Bi2O3, MgO and ZrO2 according to chemical formula doses; (2) milling thematerials by wet ball milling, mixing well, drying the mixture, pre-sintering the mixture in a muffle furnace to obtain ceramic powder; (3) ball-milling the pre-sintered powder, drying, granulating, and pressing to obtain raw ceramic; (4) debinding the raw ceramic, and sintering to obtain a ceramic sample. The preparation method is simple, low in cost, and free of lead or pollution; the prepared material herein has high discharge storage intensity of 0.31-1.45 J / cm<3> and high breakdown strength of 82-191 kV / cm.

The invention discloses a miniature super capacitor and a manufacturing method thereof, and belongs to the technical field of micro-electronic machines. The miniature super capacitor consists of a polyimide supporting body, microelectrodes, a gel-like electrolyte and a sliver seal cover, and has a winding structure, wherein each microelectrode comprises an energy storage material, a conducting material and an adhesive, and is prepared by a screen printing method; and the gel-like electrolyte is prepared by mixing polyvinyl alcohol, sodium carboxymethyl cellulose, potassium hydroxide and water, and is coated among the microelectrodes by a spin coating method. The manufacturing method can reduce the internal resistance of the miniature super capacitor and improve the energy storage property of the miniature super capacitor. The miniature super capacitor is widely used in fields of sensor network node power supplies, fuze power supplies and the like.

The invention belongs to the technical field of preparation of conductive polymer hydrogels, and provides a polypyrrole hydrogel with controllable morphology and a preparation method thereof and application of the polypyrrole hydrogel to a supercapacitor. The deficiencies and defects existing in the preparation of traditional polymer hydrogels are solved. The prepared polypyrrole hydrogel has thecontrollable morphology and excellent electrical conductivity and flexibility. The polypyrrole hydrogel is obtained by pouring dispersion liquid containing a crosslinking agent and a strong oxidant into dispersion liquid containing a polymer pyrrole monomer by one-step in-situ crosslinking polymerization, wherein the crosslinking agent is 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin, namely, TCPP, and the strong oxidant is ammonium persulfate or ferric chloride; and the molar ratio of monomer pyrrole to the crosslinking agent TCPP is (40 to 1) to (320 to 1). The polypyrrole hydrogel with thecontrollable morphology is prepared, the polypyrrole hydrogel is applied to the supercapacitor to avoid the addition of a polymer binder and a conductive active agent, and excellent energy storage performance is exhibited.

The invention discloses a strontium titanate-based ceramic material with high energy storage density and low dielectric loss and a preparation method thereof. The method comprises the following steps: preparing materials according to a chemical formula which is expressed as (1-x)SrTiO[3-x]Bi0.48La0.02Na0.48Li0.02Ti0.98Zr0.02O3, mixing uniformly to obtain raw material powder, uniformly mixing organic solvents and emulsifiers, then adding the raw material powder, adhesives, dispersants and plasticizers, mixing uniformly, carrying out tape casting, then cutting and stacking, then pressurizing, discharging glue and sintering to obtain the strontium titanate-based ceramic material with high energy storage density and low dielectric loss. The ceramic material is simple in preparation process and mature in preparation technique, and is suitable for industrial production; the energy storage density calculated on the basis of ferroelectric hysteresis loop is 1.98-2.59j / cm<3>, the energy storage efficiency is 69-87%, and the electric field intensity is 200kV / cm or more; the ceramic material is excellent in energy storage characteristic and low in dielectric loss.

The invention discloses a BCT / BZT-system lead-free monocrystal epitaxial multilayer energy storage film and a preparation method thereof. The preparation method has the advantages that the radio frequency magnetron sputtering technology is adopted, a BCT / BZT multilayer film is obtained on a substrate through plasma bombardment of target materials, films with different periods but same thicknessesare prepared through regulation of the sputtering time of the two target materials, the obtained films can have epitaxial multilayer heterostructures, part of the current paths can be stopped at the interfaces, and breakdown is effectively suppressed; as the interfaces increase, the hindrance effect of internal current branches on materials is enhanced, so that the energy storage film prepared bythe method has extremely high energy efficiency while the huge energy storage density is achieved; the energy efficiency of 8-cycle samples is more than 65%, most of them are more than 70%, and the efficiency of 4-cycle samples can be more than 80%.

The invention discloses a high-orientation layered graphene aerogel phase change composite material and a preparation method thereof, and belongs to the field of phase change energy storage. The preparation method specifically comprises the steps of carrying out hydrothermal reaction on graphene oxide suspension in a segmented heating manner to obtain reduced graphene hydrogel; performing pre-freezing treatment; performing vacuum freeze drying to obtain a layered aerogel material; performing high-temperature carbonization or graphitization treatment; and compounding with a phase change material through vacuum impregnation. The graphene aerogel prepared by the method disclosed by the invention can be repeatedly rebounded and is not easy to break; and the highly-oriented layered graphene aerogel phase-change composite material prepared by the method has excellent oriented heat-conducting property, high energy storage property and good leakproof property, and has a wide application prospect in the field of phase-change energy storage.

The power supply method for train power network on magnetic suspension train without power tracks features that the rechargeable accumulator pack powers the power network load on the train under the control of power network controller based on chaotic control policy via the power network distributor during cutoff, startup and emergency braking; the accumulator pack together with the linear power generator on the train powers the power network load on the train in low speed section; and the linear power generator on the train powers the power network load on the train while the stepup chopper of the power network on the train power the accumulator pack to ensure the 70-90 % rated capacity in high speed section. The present invention solves the technological problem for the accumulator pack in the train to power the power network on the trani without auxiliary power supply tracks.

The invention belongs to the technical field of transparent ceramic materials, and relates to a potassium sodium niobate-based transparent ceramic material and a preparation method thereof. The chemical composition of the potassium sodium niobate-based transparent ceramic material is (1-x)(K0.5Na0.5)NbO3-xSr(Sc0.5Nb0.5)O3, wherein x is larger than or equal to 10 mol% and smaller than or equal to 20 mol%. The compact and uniform transparent ferroelectric ceramic with micron-sized grains is successfully prepared by adopting a traditional solid-phase sintering technology. The ceramic prepared inthe invention shows high transmissivity (64-72% under the thickness of 0.3 mm) in visible light and near-infrared regions, and can obtain a high energy storage density of 4.45 J / cm<3> under a high breakdown field intensity (395 kV / cm); the system transparent ceramic well combines electrical and optical characteristics, realizes multifunction of electronic components, can replace a part of lead-containing ceramic, and reduces environmental pollution of heavy metals.

The invention provides a barium strontium titanate-based ceramic material as well as a preparation method and application thereof, and belongs to the technical field of energy storage ceramic materials. The chemical composition of the barium strontium titanate-based ceramic material provided by the invention is (1-x) Ba < 0.8 > Sr < 0.2 > TiO < 3-x > Bi (Mg < 2 > / 3Nb < 1 / 3 >) O < 3 >, and x is greater than or equal to 0.08 and less than or equal to 0.16. The barium strontium titanate-based ceramic material provided by the invention has high energy storage density and energy storage efficiency.Results show that the barium strontium titanate-based ceramic material provided by the invention has high dielectric relaxation and breakdown resistance, and can obtain a slender hysteresis loop; under an external electric field of 250 kV / cm, the effective energy storage density of the barium strontium titanate-based ceramic material is 2.028 J / cm < 3 >, and the energy storage efficiency reaches96.8%.

The invention discloses a hybrid minitype super capacitor and a manufacturing method thereof, and belongs to the technical field of MEMS. The minitype super capacitor is composed of a support body, a positive electrode, an isolated body, a negative electrode and aluminum seal covers, wherein the minitype super capacitor is in a coiling structure; the positive electrode, the isolated body and the negative electrode are soaked in a lithium perchlorate organic electrolyte; the positive electrode comprises an active carbon energy storage material, an acetylene black conducting material and polyvinylidene fluoride adhesive, and is prepared by a screen printing method; the negative electrode comprises a lithium titanate energy storage material, acetylene black and polyvinylidene fluoride adhesive, and is prepared by the screen printing method; the isolated body is a copolymer in a polyvinylidene fluoride-hexafluoropropylene porous structure and is prepared by a spin coating method; and the ends of the positive electrode and the negative electrode are respectively provided with the aluminum seal cover prepared by a magnetron sputtering method, and the aluminum seal covers are used as electrode terminals to perform the function of a current collector. The large contact area of the aluminum seal covers and the electrodes can effectively reduce the resistance of the minitype super capacitor, thereby enhancing the energy storage characteristic of the minitype super capacitor; and the invention can increase the voltage of the minitype super capacitor to 3.6 V.

The invention discloses a lead-free ceramic material with high energy storage density and energy storage efficiency and a preparation method thereof. The preparation method comprises the following steps of mixing materials according to a chemical formula (1-x)SrTiO3-x(0.93Bi0.5Na0.5TiO3-0.07Ba0.94La0.04Zr0.02Ti0.98O3), uniformly mixing, so as to obtain raw-material powder, uniformly mixing an organic solvent and an emulsifier, then adding the raw-material powder, a binder, a dispersant and a plasticizer, then uniformly mixing, carrying out tape casing, and then cutting, superposing, pressurizing, discharging glue and sintering, so that a strontium titanate based lead-free high-pressure-resistant ceramic energy storage material is obtained. The ceramic material provided by the invention is simple in preparation process, mature in technique, suitable for industrialized production and excellent in energy storage property, and has the energy storage density of 1.80J / cm<3> to 2.83J / cm<3>, the energy storage efficiency of 74 to 87 percent and the electric field intensity of 175kV / cm to 326kV / cm, which are calculated based on an electric hysteresis loop.

The invention discloses a DC voltage reduction discharging and single-phase inversion discharging control circuit with an adjustable battery pack serial structure. According to the circuit, discharging control can be performed on each single battery (or single battery set) through a control current conduction path. Through controlling the number of single batteries (or single battery sets) which output discharged power, adjustable DC discharging voltage is realized, or dynamic adjustment is performed for realizing single-phase inversion discharging. The circuit can realize dynamic balancing capability which is same with magnitude of discharging current. Through dynamic controlling, sufficient discharging of each single battery (or single battery set) in the battery set can be realized.

The invention provides a rod-like polyaniline / wood electrode material and a preparation method and application thereof. The method comprises the following steps: 1, the pH of an aniline aqueous solution is adjusted to 1-2 with acid, a mixed solution A is obtained, delignified wood is filled with the mixed solution A after the mixed solution A is placed in an ice-water bath, then drying is conducted, and wood containing aniline is obtained; and 2, an ammonium persulfate aqueous solution is placed in an ice-water bath, and the aniline-containing wood is filled with the ammonium persulfate aqueous solution and dried to obtain the rod-like polyaniline / wood electrode material, wherein the molar ratio of aniline in the aniline aqueous solution to ammonium persulfate in the ammonium persulfate aqueous solution is 1: (1-2). According to the invention, the rod-like polyaniline uniformly grows in the pore channels and the surface of the wood to obtain a composite material on which polyaniline wood grows, so that the transmission quantity of electrons is increased, the electrochemical performance of the material is improved, the conductivity and the structural stability of the material are improved, the internal resistance of the material is reduced, the conductivity of the material is improved, and the energy storage characteristic of the material is improved.

The invention relates to a sodium strontium barium niobate based glass ceramic energy storage material and a preparation method and application thereof. The sodium strontium barium niobate based glass ceramic energy storage material is mainly prepared from BaCO3, SrCO3, Na2CO3, Nb2O5 and SiO2. The preparation method comprises the following steps: blending the five substances according to the molar ratio as follows: BaCO3: SrCO3: Na3CO3: Nb2O5: SiO2= 33.6x: 33.6(1-x): 8.4: 28: 30, wherein the value range of x is 0-0.8; after mixing the ingredients by a ball mill, drying the ingredients, and melting at high temperature to obtain high-temperature melt; pouring the high-temperature melt into a preheated metal die, carrying out stress relief annealing to obtain transparent glass, and cutting the transparent glass into glass slices; and carrying out controlled crystallization on the glass slices to obtain the sodium strontium barium niobate based glass ceramic energy storage material. Compared with the prior art, the sodium strontium barium niobate based glass ceramic energy storage material is simple in system, the preparation method is simple, complicated aftertreatment steps are not required, the material is economic and practical, the prepared glass ceramic energy storage material has excellent dielectric property, and the energy storage characteristic of the material is improved remarkably.

The invention discloses a tubular mesoporous manganese dioxide supercapacitor and a preparation method thereof. The tubular mesoporous manganese dioxide supercapacitor is characterized in that the tubular mesoporous manganese dioxide is formed by alpha phase manganese dioxide, beta phase manganese dioxide or gamma phase manganese dioxide or mixing each two of the three crystal phases or mixing the three crystal phases, pore size distribution of each of the three crystal phases is in a range from 2nm to 50nm, tube diameter of each of the three crystal phases is in a range from 0.5micrometer to 10micrometers, the internal and external diameter ratio of the three crystal phases is larger than 0.9, and the length-diameter ratio of the three crystal phases is larger than 10. The preparation method of the tubular mesoporous manganese dioxide supercapacitor includes that cottons are soaked in a potassium permanganate aqueous solution, after drying, the cottons which absorb potassium permanganate are calcined in the air to obtain a product, and the calcined product is subjected to washing and drying to obtain a manganese oxide powder body. The tubular mesoporous manganese dioxide has good capacitance and high energy storage characteristics and can be used as an electrode material of the supercapacitor. The tubular mesoporous manganese dioxide supercapacitor and the preparation method thereof have the advantages of being simple, environment-friendly, low in cost, and good in performance and the like.

The invention relates to a material for manufacturing a solid-state energy storage capacitor, which is made by the following main materials in percentage by weight: 54.90-57.78 percent of lead oxide, 24.29-28.21 percent of zirconium oxide, 5.62-8.86 percent of titanium oxide, 4.68-5.52 percent of lanthanum oxide, 0-4.80 percent of barium carbonate, 0.67-0.71 percent of silver oxide and 0-1.43 percent of bismuth oxide. The material has the beneficial effects that the capacitance of the capacitor prepared by the material can present a better upward trend within a wider operating temperature range (55 DEG C below zero-125 DEG C above zero), and a dielectric constant of the capacitor is larger than 1,500; moreover, the capacitance of the capacitor has a positive voltage temperature coefficient after rated voltage is applied; and particularly, the upward trend of a positive capacitance-temperature characteristic curve is basically consistent with that of a positive capacitance-voltage characteristic curve, and the requirements of the solid-state energy storage capacitor on the material are completely met.

The invention discloses a barium titanate-based superparaelectric film material, a method for integrally preparing a barium titanate-based superparaelectric film on a silicon substrate at medium and low temperatures and application of the barium titanate-based superparaelectric film material. The method comprises the steps that under the condition of room temperature (without heating) or 150 DEG C, a buffer layer and a barium titanate base film are sequentially subjected to magnetron sputtering on the surface of a platinum-titanium-plated base body from bottom to top, a top electrode is subjected to magnetron sputtering on the surface of the barium titanate base film, and the buffer layer is made of conductive oxide lanthanum nickelate which can be matched with barium titanate base lattices and is of a perovskite structure; the sputtering mode is a continuous sputtering mode of the lanthanum nickelate buffer layer and the barium titanate base film. According to the invention, the temperature for preparing the barium titanate-based membrane material can be reduced to room temperature or 150 DEG C, and the barium titanate-based membrane material has a nano polar region with good dispersion, high energy storage density and high energy storage efficiency, and high energy storage characteristics are not changed along with the increase of thickness. Moreover, by reducing the thickness of the superparaelectric film layer, the capacitance density and the dielectric constant are increased, and the requirement of a thin film transistor for the high dielectric constant of the dielectric layer is met.

The invention provides a method for preparing a three-dimensional graphene structure through 3D printing. According to the method, a laser selective carbonization technology is utilized, polymer powder is taken as a raw material, the polymer powder is directly converted into a graphene structure, and a three-dimensional graphene structure is obtained through layer-by-layer accumulation. In addition, by designing and researching the influence of parameters such as laser processing conditions and powder laying thickness on the forming and performance of the three-dimensional graphene structure and by adopting a post-treatment process, the homogeneity, the specific surface area, the porosity and the electric conductivity of the material are greatly improved; and therefore, the material has higher specific capacitance, energy density and power density when being applied to a supercapacitor electrode material. The efficient and reliable three-dimensional graphene forming method is provided, and the comprehensive performance of the three-dimensional graphene is improved while the appearance of the three-dimensional graphene is maintained.

The invention relates to the field of energy storage thin-film materials and discloses a lead-free epitaxial thin film with wide working temperature and a preparation method thereof. The lead-free epitaxial thin film comprises a Nb:SrTiO3 substrate and a thin film body, wherein the thin film body is arranged on the upper surface of the Nb:SrTiO3 substrate; the thin film body is Ba0.3Sr0.7TiO3 / 0.85BaTiO3-0.15Bi(Mg0.5Zr0.5)O3 composite multilayer thin film; and the structure of the lead-free epitaxial thin film is Nb:SrTiO3 / Ba0.3Sr0.7TiO3 / 0.85BaTiO3-0.15Bi(Mg0.5Zr0.5)O3. The lead-free epitaxialthin film with wide working temperature does not contain lead and has excellent energy storing property, and more importantly, the lead-free epitaxial thin film has high thermal stability within the wide temperature area of 25-250 DEG C, and the working temperature of the lead-free epitaxial thin film is far higher than that of other lead-free thin films.

The invention provides a vacuum heat insulation type heat / cold storage device which comprises a shell, wherein the shell is filled with an energy storage medium, the shell comprises a shell inner wall, a vacuum layer, a heat preservation layer and a shell outer wall, and the shell inner wall, the vacuum layer, the heat preservation layer and the shell outer wall are sequentially arranged from inside to outside. According to the vacuum heat insulation type heat / cold storage device provided in the invention, the temperature field stability of the heat / cold storage device in the alternating process of energy storage and energy release can be improved, and the energy storage characteristic of the heat / cold storage device is effectively improved.