627results about "From solid state" patented technology

A method of synthesis of single crystal nickel-rich cathode materials can include preparing a precursor solution by dissolving lithium nitrate, nickel nitrate, manganese nitrate, and cobalt nitrate in water, aerosolizing the solution of a) in a stream of air using an ultrasonic sprayer, preheating the resulting droplets, premixing the droplets with methane, decomposing the droplets by passing through a co-flow burner, depositing solid particles on a filter, and calcinating the solid particles in a furnace in oxygen to produce a single crystal cathode material.

The present invention provides a single-crystal lithium-rich manganese-based positive electrode precursor and its preparation method and application. The single-crystal lithium-rich manganese-based positive electrode precursor comprises secondary particles formed by primary particles and satisfies the following relationship: 1.2μm≤D50≤1.8μm, 0.5μm≤D R <6.0μm, 0.5g / cm 3 ≤α≤0.8g / cm 3 , 30m 2 / g≤β≤50m 2 / g, 22≤α·β≤28, 20nm≤N≤45nm, 5≤M / N≤10, wherein D50 is the median particle size of the secondary particles, D R is the particle size of the secondary particles, α is the tap density of the secondary particles, β is the specific surface area of ​​the secondary particles, N is the average thickness of the primary particles, and M is the average length of the primary particles. The median particle size of the secondary particles of the single-crystal-like lithium-rich manganese-based positive electrode precursor provided by the present invention is no more than 1.8 μm, which is significantly lower than the reported particle size of (quasi) single-crystal lithium-rich positive electrode precursors. The precursor can be made into a submicron-level single-crystal-like lithium-rich manganese-based positive electrode material with excellent dispersibility.

The invention relates to a nano silicon carbide whisker and a preparation method thereof, and the preparation method comprises the following steps: (1) carrying out acid process treatment on fly ash by using an acid solution, so that the content of key impurity elements in the fly ash accounts for 2-11% of the total mass of the treated fly ash, and obtaining acid-treated fly ash; (2) mixing the acid-treated fly ash with a first carbon source to obtain a mixture; and (3) covering the mixture with a second carbon source, roasting in a reducing atmosphere to obtain a roasted material which comprises a nano silicon carbide whisker layer and a total impurity layer positioned below the silicon carbide whisker layer, and removing the total impurity layer to obtain the nano silicon carbide whisker. According to the preparation method, the low-cost fly ash is taken as a raw material, the advantages of low preparation cost and relatively high product yield can be taken into account through the synergistic effect of moderate acid treatment, raw material position setting and roasting in the reducing atmosphere, and good morphology and relatively high purity of the nano silicon carbide crystal whiskers are ensured.

The invention discloses a preparation method of a perovskite thin film and a perovskite cell, and relates to the technical field of solar cells. The preparation method of the perovskite thin film comprises the following steps: forming a mixed layer containing PbI2 on a substrate as a metal halide framework layer; coating the metal halide framework layer with an organic ammonium salt solution containing a crystallization regulating agent to obtain a first device; wherein the crystallization regulating agent contains a guanidine group; and carrying out annealing treatment on the first device to obtain the perovskite thin film. According to the perovskite thin film, the problems that perovskite prepared in the prior art is small in grain size and uneven in interface can be solved, and the performance of the perovskite thin film is improved.

The invention belongs to the technical field of lithium ion battery materials, and discloses a preparation method of a high-first-effect small-particle single-crystal ultrahigh-nickel ternary positive electrode material. The method comprises the following steps: firstly, uniformly mixing an ultrahigh nickel ternary precursor with a lithium source and a tungsten source, performing mechanical densification and pressing to obtain a blocky solid, and then performing four-section program temperature control calcination to obtain a target material. The interface fusion resistance of single crystal growth can be reduced through mechanical densification; a part of the tungsten element forms a Li2WO4 coating layer, and a part of the dopant phase replaces Ni < 2 + >, so that grain growth can be inhibited, a crystal structure can be stabilized, and the first effect is improved; and the microstructure of the material can be accurately regulated and controlled through four-section temperature-controlled calcination. Through a coating-doping-single crystallization synergistic strategy, the electrochemical performance of the material in liquid and sulfide-based all-solid-state batteries is remarkably improved, the process is controllable, and the application prospect is wide.

A silicon carbide seed is provided, including a first seed layer and a second seed layer. The first seed layer includes a polycrystalline silicon carbide material. The second seed layer is directly attached to the first seed layer, where the second seed layer includes a single crystal silicon carbide material, and a thickness ratio (T2 / T1) of a thickness T1 of the first seed layer to a thickness T2 of the second seed layer is in a range of 10% to 50%.

The invention discloses a high-voltage single-crystal positive electrode material as well as a preparation method and application thereof, and belongs to the technical field of lithium ion batteries. The preparation method comprises the following steps: by taking MOFs (Metal Organic Frameworks) with a porous structure as a template, loading a ternary precursor in pore channels of the template by adopting a solvothermal method to prepare loaded MOFs; mixing the loaded MOFs with a lithium source, carbonizing and calcining in an inert atmosphere for high-temperature solid-phase reaction, carbonizing the template to form a nitrogen-doped porous carbon skeleton, and converting the ternary precursor into single-crystal NCM particles to prepare a calcined product; sequentially carrying out acid pickling, drying and airflow crushing treatment on the calcined product to obtain a composite material; the composite material is sequentially subjected to multi-section penetration type dry coating and sintering treatment, the high-voltage single-crystal positive electrode material is prepared, and the high-voltage single-crystal positive electrode material can balance the capacity, the cycle life and the safety under high voltage.

The present description belongs to the technical field of battery materials. Disclosed are a single-crystal ternary positive electrode material, a preparation method therefor, a positive electrode sheet and a battery. The apparent factor of the single-crystal ternary positive electrode material is [Formula 1], wherein 1.1≤Z≤3, x=D90 / D10, 2≤x≤5; S(D90) is the number averaged circularity, the total number of target particles is n, and the number averaged circularity is defined as the sum of circularity values of all of the target particles divided by n. The area and circumference corresponding to a two-dimensional projection image of a single target particle are respectively S1 and l1, the circumference of a circle having the area S1 is l2}, and the circularity = l2 / l1. The D10' is the corresponding particle size of a material obtained by compacting the single-crystal ternary positive electrode material at 200 MPa, D10 does not exceed 2.4 μm, and D10' does not exceed 2.3 μm. The single-crystal ternary positive electrode material has smooth surfaces and rounded edges, which are beneficial for fabricating batteries having excellent electrochemical properties.

The invention relates to a method for preparing a single-crystal lithium-rich manganese-based positive electrode material by synergistically regulating and controlling a deep eutectic solvent and aluminum gradient doping, which comprises the following steps of: carrying out multi-stage aluminum gradient doping to prepare a single-crystal lithium-rich manganese-based positive electrode material by synergistically regulating and controlling the deep eutectic solvent and the aluminum gradient doping; multi-level regulation and control on the structure of the positive electrode material from the inside to the surface are realized; the formation of an inducible single-crystal structure is assisted by the deep eutectic solvent; through addition of phosphorus / boron-containing anions and microwave strengthening treatment, oxygen vacancy lattice repair is promoted; carbon in-situ coating treatment is realized by adding a carbon source, so that the conductivity and interface stability of the material are improved; and lithium defects caused by other steps can be compensated through pre-lithiation treatment, and the first coulombic efficiency is improved. And five parts are integrated, so that the structural stability, the electrochemical performance and the safety of the material are multiply improved.

The invention provides a single-crystal cobalt-free lithium-rich manganese-based positive electrode material as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing a cobalt-free lithium-rich manganese-based precursor material, a lithium source and a grain boundary separation auxiliary agent to obtain a mixed material; the mixed material is subjected to two-stage sintering, the two-stage sintering comprises first sintering and second sintering in sequence, and the single-crystal cobalt-free lithium-rich manganese-based positive electrode material is obtained, wherein primary crystal grains of the cobalt-free lithium-rich manganese-based precursor material are of a sheet structure. According to the invention, the cobalt-free lithium-rich manganese-based precursor material of which the primary crystal grains are of a sheet structure is taken as a raw material, and under the action of the grain boundary separation auxiliary agent, a two-stage sintering process is cooperatively matched, so that the single-crystal cobalt-free lithium-rich manganese-based positive electrode material which is uniform in grain size, high in dispersity, complete in crystal grains and continuous in interface is obtained, and the cobalt-free lithium-rich manganese-based positive electrode material is not only suitable for a liquid lithium ion battery, but also suitable for a lithium ion battery. The material is more suitable for a solid-state lithium ion battery, and the electrochemical performance of the battery is effectively improved.

The present application relates to a cathode material precursor, a single-crystal cathode material and a preparation method thereof, and a lithium ion battery. A general chemical formula of the single-crystal cathode material is LixNiaCobMncNdO2, where 0.98≤x≤1.1, 0.50≤a≤0.98, 0< b≤0.20, 0<c≤0.30,0≤d≤0.10, a+b+c+d=1, and N includes at least one of Al, Ti, Zr, Mg, Sr, Ba, Ca, Nb, W, Sb, Ta, Sn, or Y; a standard deviation of a mass content of each element of Ni, Co, and Mn in the single-crystal cathode material is ≤0.03; and lattice strain is ε<0.2%. According to the single-crystal cathode material provided in the present application, the lattice strain is low, diffusion energy barriers of lithium ions among crystallite can be reduced, such that a material shows low DCR and good rate performance; and generation of microcracks can also be inhibited, thereby improving the cycling performance of the material.

The invention discloses a method for directly regenerating a failed battery positive electrode material into a single-crystal high-voltage positive electrode based on size regulation and application. The method comprises the following steps: mixing the polycrystalline NCM positive electrode material of the failed battery with low-melting-point molten salt, performing low-temperature pre-sintering lithium supplementation, and performing high-temperature annealing to realize grain size regulation and structure optimization, thereby finally obtaining the high-voltage positive electrode material with a single-crystal structure. The method is short in technological process, low in energy consumption and small in environmental pollution, the regenerated positive electrode material has excellent electrochemical performance and is suitable for a high-voltage (larger than or equal to 4.4 V) lithium ion battery, and efficient and high-added-value recycling of the failed battery positive electrode material is achieved.

The invention belongs to the technical field of ternary positive electrode materials, and particularly relates to a preparation method of a low-cation mixed ternary positive electrode single crystal material. The preparation method comprises the following steps: uniformly mixing a pre-oxidized precursor, a lithium source and a doping additive, performing high-temperature primary sintering in a strong oxidizing atmosphere, then crushing to obtain a primary sintering base material with a target particle size, and then coating and secondarily sintering the primary sintering base material to obtain a target product. According to the preparation method, Ni < 2 + > in a material matrix is more fully oxidized into Ni < 3 + > through strong pre-oxidation of the ternary precursor and a strong oxidation process during high-temperature sintering, so that the cation mixing degree in the material is further reduced, and the electrochemical performance, including the charge-discharge capacity, the rate capability and the cycle service life, of the single-crystal ternary material is improved. Meanwhile, doping elements are combined, so that the preparation process and the mechanical strength of the material are improved in a targeted manner, and the stability of the material is further improved. Therefore, the method has a wide market application prospect. Meanwhile, the preparation method is simple, and industrial large-scale production is easy.

The invention belongs to the field of preparation of a lithium ion battery positive electrode material, and particularly relates to high-voltage type single crystal lithium manganate, a preparation method and application of the high-voltage type single crystal lithium manganate. According to the scheme, a manganese source compound, a lithium source compound and a transition metal oxide are mixed according to the molar ratio of 1: (0.5-0.6): (0.1-0.3), deoxidized and sintered, and a single-crystal lithium manganate intermediate product is obtained; and preparing a finished product by taking the obtained intermediate product as a raw material. The deoxidation sintering operation comprises the steps of heating from room temperature to 800-1000 DEG C at a heating rate of 20-30 DEG C / min, keeping the temperature for 2-6 hours, not carrying out heat preservation operation in the heating process, cooling to 400-500 DEG C at a cooling rate of 50-100 DEG C / h after the constant temperature stage is ended, and keeping the temperature for 2-4 hours, so as to prepare the high-voltage type single crystal lithium manganate positive electrode material. According to the scheme, the capacity and the high-temperature cycle performance of the lithium manganate material can be remarkably improved and the expansion rate of the battery can be inhibited under the cooperation of the doping elements with rapid heating, gradient cooling and radius matching. Meanwhile, the invention also provides an application of the high-voltage single-crystal lithium manganate positive electrode material in a battery.

The invention provides a whisker / fiber secondary structure composite film layer flexible thermal insulation material and a preparation method thereof, and belongs to the technical field of flexible thermal insulation materials. The preparation method comprises the following steps: preparing spinning sol from AN, TEOS, AIP, PEO, PVA, PVP and a porous thermal insulation material as raw materials, carrying out electrostatic spinning to prepare a fiber membrane, pre-sintering the fiber membrane, loading AlF3 and SiO2, and finally sintering to catalyze a secondary structure. Through structural design, whisker secondary structures which are different in direction and can be mutually lapped to form a frame grow on a fiber main body of the fiber membrane, the mechanical property of the fiber membrane layer is guaranteed, meanwhile, the porosity of the fiber membrane layer is further improved, the microstructure of the fiber membrane layer is improved, and the effect of reducing the thermal conductivity of loaded aerogel is developed. And another new way is provided for improving the thermal insulation performance of the composite material. The thermal conductivity of the obtained thermal insulation material is lower than 0.038 W / (m.K).

The invention discloses a preparation method of a potassium-sodium niobate-based single crystal, the chemical formula of the potassium-sodium niobate-based single crystal is # imgabs0 # x representing the mole fraction of Co element in a system, 0 < x < = 0.005, pre-seed crystals prepared by a seed-crystal-free solid-phase crystal growth method are subjected to surface growth residue and attachment removal, polishing, thinning and related treatment, and the potassium-sodium niobate-based single crystal is obtained. According to the method, the potassium-sodium niobate and the powder are pressed together to form a seed burying blank, the large-size potassium-sodium niobate-based single crystal grows through seed crystal induction, the advantages of a seed crystal-free solid phase method and a traditional solid phase method are combined, the stability of single crystal growth is ensured, and regulation and control of the growth orientation and size increase of the single crystal can be realized through accurate control of the seed crystal; the introduction of impurities can be avoided, and the repeatability and stability of single crystal growth are improved.

The invention discloses a monocrystal lithium nickel manganese oxide positive electrode material for a lithium ion battery as well as a preparation method and application of the monocrystal lithium nickel manganese oxide positive electrode material. The method comprises the following steps: preparing a spherical hydroxide precursor composed of nanosheet crystal grains, converting the spherical hydroxide precursor into a stable biphase mixture of Mn2O3 and MnNiO3, and sintering the biphase mixture with a lithium source in an oxygen atmosphere at 950-1100 DEG C to generate single crystal lithium nickel manganese oxide LiNi < x > Mn < 2-x > O < 4 >, xlt; and 0.6. The monocrystal lithium nickel manganese oxide prepared by the method is of a square or octahedral structure, the grain size is 1-11 microns, the capacity is more than 134mAh / g, the rate and cycle performance are excellent, high energy density and high power density can be realized at the same time, and the service life is long.

A lithium-nickel-cobalt-manganese positive electrode material and a preparation method therefor, a positive electrode and a battery, relating to the technical field of battery materials. The lithium-nickel-cobalt-manganese positive electrode material comprises a lithium-nickel-cobalt-manganese single crystal and a modification layer located at an internal interface of the lithium-nickel-cobalt-manganese single crystal. The modification layer is generated by a reaction of Li, A, B and oxygen, wherein element A is selected from at least one of elements W, Mo and Re, and element B is selected from at least one of Ba and Ca. The preparation method for the lithium-nickel-cobalt-manganese positive electrode material comprises: uniformly mixing a nickel-cobalt-manganese precursor, a lithium source, an additive A and an additive B, and sintering the mixture. According to the preparation method, a lithium-nickel-cobalt-manganese positive electrode material can be prepared. The preparation method is simple, and the prepared positive electrode material has good electrochemical performance.

The invention discloses a preparation method of high-purity aluminum nitride single crystal powder. The method comprises the following steps: uniformly mixing raw materials aluminum powder and aluminum nitride powder according to a ratio, putting the mixture into an air pressure sintering furnace, vacuumizing, introducing high-pressure argon, heating to a set temperature, introducing nitrogen, carrying out a fire blast reaction, cooling to room temperature, and crushing to obtain the high-purity aluminum nitride single crystal powder with D50 of 20-200 microns. According to the method, the synthesis of the coarse-particle high-purity aluminum nitride single crystal powder is realized by utilizing the rapid nitridation explosion reaction of the aluminum powder in the high-temperature and high-pressure nitrogen, the method has the characteristics of simple process and low preparation cost, and the prepared high-purity aluminum nitride single crystal powder can be used as a high-thermal-conductivity filler for electronic packaging.

The invention discloses a multi-element differentiated distribution co-doped single-crystal high-nickel positive electrode material and a preparation method and application thereof.The material is doped with a first doping element and a second doping element, the first doping element is in gradient distribution with the concentration gradually increased from inside to outside in material particles, and the second doping element is in gradient distribution with the concentration gradually increased from inside to outside. The second doping elements are basically and uniformly distributed in the material particles; the first doping element is used for strengthening the surface stability of the material, and the second doping element is used for stabilizing the bulk phase structure of the material. The material is obtained by taking a lithium salt and a ternary positive electrode material precursor as raw materials, introducing a first doping source and a second doping source, mixing, ball-milling and calcining according to a preset stoichiometric ratio.

To provide a piezoelectric element that can achieve both a high electromechanical coupling coefficient and a high coercive field and that is compatible with a wider range of perovskite oxide single crystals, and may contribute to the realization of a sustainable society, such as a decarbonized / recycling-based society.SOLUTION: A piezoelectric element having a single crystal of a perovskite metal oxide and opposing electrodes, wherein when the ambient temperature is 25°C, the crystal system of the single crystal is tetragonal, and the crystal orientation of the surface of the single crystal that contacts the electrode surfaces of the opposing electrodes is (110) or (111).SELECTED DRAWING: Figure 1

The application belongs to the field of lithium ion battery cathode material preparation, and particularly relates to a high-voltage type single-crystal lithium manganate, a preparation method and application thereof. The scheme mixes a manganese source compound, a lithium source compound and a transition metal oxide according to a molar ratio of 1:0.5-0.6:0.1-0.3, deoxidizes and sinter, to obtain a single-crystal lithium manganate intermediate product; the obtained intermediate product is used as a raw material to prepare a finished product; the deoxidizing and sintering operation is to raise the temperature from room temperature to 800-1000 DEG C at a temperature raising rate of 20-30 DEG C / min, and keep constant temperature for 2-6 h, no temperature keeping operation is performed in the temperature raising process, after the constant temperature stage is finished, the temperature is lowered to 400-500 DEG C at a temperature lowering rate of 50-100 DEG C / h, and keep constant temperature for 2-4 h, to prepare the high-voltage type single-crystal lithium manganate cathode material. The scheme can significantly improve the capacity and high-temperature cycle performance of the lithium manganate material, and inhibit the battery expansion rate, through fast temperature raising, gradient temperature lowering and the cooperation of radius-matched doping elements. Meanwhile, the application also provides application of the high-voltage type single-crystal lithium manganate cathode material in a battery.

This invention belongs to the field of single-crystal material preparation technology, specifically relating to a molybdenum trioxide single-crystal ribbon and its preparation method. During the calcination of a molybdenum source, the ribbon is contacted with a structure-directing agent composed of alkali metal salts and metals other than molybdenum in Group 6, or alkaline earth metal salts and metals other than molybdenum in Group 6. After cooling, the molybdenum trioxide single-crystal ribbon is obtained. This invention does not require complex template guidance, the structure-directing agent is simple and readily available, and it enables molybdenum trioxide crystals to grow along a specific direction, resulting in a highly crystalline molybdenum trioxide single-crystal ribbon.

The invention provides a perovskite pseudo-single crystal thin film and a preparation method thereof. The preparation method comprises the following steps: (1) preparing a perovskite polycrystalline thin film on a hydrophilic substrate; (2) pressing a hydrophobic substrate on the perovskite polycrystalline thin film to obtain a sandwich structure; (3) performing hot-pressing annealing treatment on the sandwich structure; and (4) after hot-pressing annealing treatment, removing the hydrophilic substrate and the hydrophobic substrate to obtain the perovskite pseudo-single crystal film. On the basis of the hot pressing technology, full diffusion, dissolution and recrystallization of crystal grains are promoted, the perovskite quasi-single crystal thin film with large crystal grains, low defects and high orientation is formed, and the method is suitable for various perovskite materials, simple in process, good in repeatability and capable of meeting the actual requirements of novel photoelectric devices.

The invention relates to a biphase P2-O3 type single crystal sodium ion layered oxide positive electrode material and a preparation method and application thereof, the biphase P2-O3 type single crystal sodium ion layered oxide positive electrode material is of a core-shell structure, the core is P2 phase sodium ion layered oxide, and the shell is O3 phase sodium ion layered oxide. According to the invention, the O3 phase is generated in situ on the surface of the P2-phase particle in a mode of supplementing the sodium source and carrying out high-temperature secondary sintering, and the formed composite-phase single crystal particle is of a special double-phase structure with a core P2 phase, so that the specific capacity, the structural stability and the cycle performance of the material are improved, and the problem of insufficient performance of a double-phase layered oxide positive electrode material in the prior art is solved.

The present application discloses a SiC substrate and a SiC crystal with uniform three-dimensional directional stress distribution, belonging to the technical field of SiC production and processing. The SiC substrate includes a first surface layer, a second surface layer and an intermediate layer; on the same axis, at any plane parallel to the first main surface or the second main surface in the first surface layer, Smax1 represents the maximum absolute value of the radial stress in the first surface layer, Smax2 represents the maximum absolute value of the radial stress in the intermediate layer, Smax3 represents the maximum absolute value of the radial stress in the second surface layer, △S1 = Smax2 - Smax1, △S2 = Smax2 - Smax3, -15 MPa ≤ △S1 ≤ 10 MPa, -15 MPa ≤ △S2 ≤ 10 MPa. The radial stress in the SiC substrate in the above first surface layer, second surface layer and intermediate layer is relatively low, and the stress distribution uniformity between each layer is good, which can improve the quality of the SiC substrate, expand the use range of the SiC substrate, and is beneficial to the production and processing of downstream epitaxial wafers and crystals.

This application relates to a P-type gallium oxide and a preparation method thereof. The preparation method of the P-type gallium oxide includes providing a substrate, the material of the substrate includes β-gallium oxide, and a co-doping of shallow-level acceptor impurities and deep-level acceptor impurities is formed on the substrate. Among them, the shallow-level acceptor impurities are elements of the same group as oxygen. When the deep-level acceptor impurities and the shallow-level acceptor impurities are co-doped, the deep-level acceptors of the deep-level acceptor impurities can combine with the acceptor levels of the shallow-level acceptor impurities, further pushing the Fermi level towards the valence band top. This combined effect significantly improves the stability of P-type conductivity of β-gallium oxide.

The invention relates to the technical field of preparation of single crystal materials, in particular to a low-cost lead-free piezoelectric single crystal with high piezoelectric response and a preparation method, the lead-free piezoelectric single crystal is of a lead-free perovskite structure, the chemical general formula of the lead-free piezoelectric single crystal is xBi < 0.5 > Na < 0.5 > TiO < 3-y > Bi < 0.5 > K < 0.5 > TiO < 3-(1-x-y) Bi < 0.5 > Li < 0.5 > TiO < 3 >, x is equal to 0-1, y is equal to 0-0.2, and x is equal to 0-1. The preparation method comprises synthesis of a multi-component lead-free precursor polycrystalline material, interface construction of a seed crystal and a polycrystalline substrate, and a high-temperature solid-phase epitaxial growth process. The components and various key process parameters of the material involved in the invention are finely controlled, the process window in the preparation process is narrow, reverse analysis is not easy to occur, and the preparation method has a remarkable technical barrier and is suitable for industrial popularization as a key preparation technology of the high-performance lead-free piezoelectric single crystal material.

A semiconductor film comprising a solid phase crystallized product of tin and hydrogen-doped indium oxide.

The invention discloses a barium carbonate doped potassium-sodium niobate-based piezoelectric single crystal and a preparation method thereof, the barium carbonate doped potassium-sodium niobate-based piezoelectric single crystal has a chemical general formula of (1-x) (K < 0.498 > Na < 0.498 > Li < 0.004 > Nb < 0.9955 > Bi < 0.004 > Fe < 0.0005 > O < 3 >)-xBaCO3, 0.001 < = x < = 0.009, and x represents a mole fraction. The preparation method comprises the following steps: taking Na2CO3, K2CO3, Nb2O5, Li2CO3, Bi2O3, BaCO3 and Fe2O3 as raw materials, adopting a seedless solid-phase crystal growth method, and carrying out primary refinement ball milling, pre-sintering, secondary refinement ball milling and sintering to prepare the barium carbonate doped potassium sodium niobate based single crystal. According to the method, the collaborative optimization of the piezoelectric property and the temperature stability is realized while the growth of the large-size single crystal is ensured.