59 results about "Lithium doping" patented technology

The invention relates to the technical field of lithium ion batteries, in particular to a lithium-doped silicon-carbon composite material, a preparation method thereof, a negative plate and a lithium ion battery. The preparation method of the lithium-doped silicon-carbon composite material comprises the following steps: carrying out reduction reaction and activated pore-forming on a mixed material containing a carbon source, an organic pore-forming agent, a lithium supplement agent and a reducing agent to obtain lithium-doped porous carbon; performing first deposition on the lithium-doped porous carbon and mixed gas containing an inorganic lithium compound and an organic lithium compound; carrying out second deposition on the material obtained after the first deposition and silane gas to obtain a lithium compound doped silicon carbon precursor material; and mixing the lithium compound doped silicon carbon precursor material, an organic metal compound, asphalt and an organic solvent, performing spray drying, and then performing carbonization. According to the preparation method, the initial efficiency and the power performance of the silicon-carbon composite material can be improved.

The invention discloses a porous carbon-coated graphite composite material for an energy storage battery and a preparation method of the porous carbon-coated graphite composite material. The porous carbon-coated graphite composite material consists of inner core graphite and lithium heteroatom-doped porous carbon coated on the surface of the inner core graphite, the preparation method comprises the following steps: preparing an organic template agent solution, adding resin and an amino organic lithium compound, uniformly mixing, adding a hydrogen peroxide oxidizing agent, reacting, filtering, and activating at high temperature to obtain lithium-doped porous carbon; the preparation method comprises the following steps: adding lithium-doped porous carbon into an organic solvent, then adding graphite and an organic aluminum-based compound, uniformly dispersing, dropwise adding an amino solution, carrying out chemical reaction at the temperature of 50-120 DEG C, filtering, and carrying out vacuum drying and high-temperature carbonization on obtained filter residues to obtain the lithium-doped porous carbon composite material. The cycle performance and the storage performance of the graphite can be improved.

The embodiment of the invention provides an alpha-Ga2O3 / Li doped NiO vertical heterojunction detector and a preparation method and application thereof, and relates to the technical field of semiconductor materials. The preparation method of the detector comprises the following steps: S1, preparing a gallium source precursor aqueous solution, and enabling the gallium source precursor aqueous solution to epitaxially grow an alpha-Ga2O3 film layer on a substrate through an atomization chemical vapor deposition technology; s2, preparing a nickel source precursor aqueous solution, adding a lithium source into the nickel source precursor aqueous solution, and epitaxially growing a Li-doped NiO film layer on the alpha-Ga2O3 film layer by using the lithium-doped nickel source precursor aqueous solution through an atomization chemical vapor deposition technology; and S3, depositing a first electrode layer on the Li-doped NiO film layer by adopting a magnetron sputtering technology, and depositing a second electrode layer on the Li-doped NiO film layer by adopting a magnetron sputtering method or depositing the second electrode layer on the alpha-Ga2O3 film layer by adopting an electron beam evaporation technology. According to the invention, the Mist-CVD technology is adopted for the first time to successfully prepare the alpha-Ga2O3 / Li-doped NiO vertical heterojunction, and the alpha-Ga2O3 / Li-doped NiO vertical heterojunction is applied to a solar-blind ultraviolet photoelectric detector.

The invention belongs to the technical field of lithium batteries, and relates to a preparation method of a double-coated silicon-carbon composite material, an electrode and a lithium battery, the method comprises the following steps: soaking a lithium dopant and an MOF material in a first organic solvent, adding a template agent and a catalyst, reacting, filtering, and freeze-drying to obtain a gel complex; in an inert atmosphere, heating the gel complex to a first preset temperature, introducing carbon dioxide according to a preset flow rate, cooling, adding into mixed acid, soaking, pickling, and drying in vacuum to obtain a porous carbon composite material; adding liquid silane, a phosphorane derivative, a dispersing agent, the porous carbon composite material and a silane coupling agent into a second organic solvent, performing spray drying, and performing primary carbonization to obtain a silicon-carbon precursor material; dissolving the resin in a third organic solvent, adding an ionic conductor and a silicon-carbon precursor material, carrying out secondary carbonization, cooling to a second preset temperature, and introducing a reducing gas to obtain a double-coated silicon-carbon composite material; the conductivity is improved, the interface stability is improved, and the full-charge expansion is reduced.

The invention discloses a lithium manganese iron phosphate positive electrode material and a preparation method thereof, and belongs to the technical field of lithium batteries. Through an integrated process of magnetic field-gradient coprecipitation + in-situ lithium doping-spray drying-segmented calcination, Fe3O4 magnetic seeds are added into a mixed metal solution, magnetic field induction is combined, pH is precisely controlled to be gradually reduced from 9 to 8 in cooperation with a triammonium citrate solution, and meanwhile, a magnetic seed-carbon layer dual conductive network is constructed; compared with the prior art, the preparation method has the advantages that the precursor dispersity, grain orderliness and purity of the lithium manganese iron phosphate positive electrode material are improved, the Li < + > migration path and electron conduction efficiency are optimized, the 5C discharge specific capacity of the material reaches 121-132mAh / g, the 500-time cycle capacity retention rate reaches 90.3-94.1%, and the first charge-discharge efficiency reaches 95.5-97.2%.

Provided are a negative electrode active material which includes negative electrode active material particles which includes a silicon oxide (SiOx, 0<x≤2); and at least one lithium silicate selected from Li2SiO3, Li2Si2O5, and Li4SiO4 in at least a part of the silicon oxide. A signal generated in a region of 200 to 600 cm−1 according to a Raman spectrum is subjected to deconvolution into three peaks, which are set to peak A, peak B, and peak C from lowest to highest of an absolute value of a wavenumber. Also disclosed are a method of preparing the same, and a negative electrode and a lithium secondary battery including the negative electrode active material.

This invention relates to the field of lithium-ion battery technology, specifically to a composite electrode material and its preparation method. The preparation method includes the following steps: using tin, red phosphorus, and lithium salt in a molar ratio of 3.5–3.9:3:0.5–0.1 as raw materials, ball milling is performed in an inert gas to obtain lithium-doped tin phosphide material; the lithium-doped tin phosphide material and carbon nanotube material are mixed uniformly, and calcined under a protective atmosphere to construct a carbon conductive network on the surface of the lithium-doped tin phosphide material to obtain modified tin phosphide material; the modified tin phosphide material is mixed uniformly with additives to obtain the composite electrode material. This invention achieves multi-dimensional modification of tin phosphide anode material through stepwise synergistic processing, solving the technical problem of decreased electrochemical performance of existing tin phosphide anode materials due to volume expansion and lithium loss.

The present invention discloses a manganese-based polyanion positive electrode material and its preparation method and application, belonging to the technical field of sodium ion battery positive electrode materials. The present invention discloses a positive electrode material, the chemical formula of which is Na x Li y MnV 0.5 Ti 0.5 (PO4)3, where 3≤x≤3.5, 0≤y≤0.5, and x+y=3.5. Due to the introduction of lithium ions, the electron orbital overlap between the alkaline metal ions and the oxygen atoms is weakened, thereby making the oxygen atoms and the surrounding Mn 2+ This enhanced Mn-O bond suppresses the Mn-O bond generated by Mn during charge and discharge. 3+ (Mn 2+ Jahn-Teller distortion caused by oxidation at high potential); this manganese-based polyanion positive electrode material can significantly improve the cycle stability and rate performance of the material while ensuring the sodium storage capacity, and its sodium storage electrochemical performance is significantly better than that of pure phase materials without lithium doping.

The application provides a double-coating lithium iron phosphate positive electrode sheet, a preparation method and application thereof. The preparation method comprises the following steps: mixing modified large-particle lithium iron phosphate, modified small-particle lithium iron phosphate, a conductive agent, a binder and a solvent to obtain a first slurry and a second slurry; adopting double-layer slot extrusion coating to coat the first slurry on the surface of a current collector and coat the second slurry on the surface of the first slurry; and drying and rolling to obtain the double-coating lithium iron phosphate positive electrode sheet; the modified large-particle lithium iron phosphate is doped with Ti and Nb, and the modified small-particle lithium iron phosphate is doped with Mg and Al. The application adopts a multi-element doped positive electrode material combined with a double-layer coating preparation method to avoid the shortcomings of LFP materials, improve the rate performance, high-temperature performance and cycle performance of LFP, and has the advantages of simple preparation process and easy industrial production. The prepared positive electrode material and the secondary battery using the same have excellent comprehensive performance, and have a wide application prospect in the field of power batteries.

The application discloses a first main group metal gradient doped Cs2NaBiCl6 perovskite material and a preparation method and application thereof, and belongs to the technical field of photocatalytic material for preventing and treating air pollution. The preparation method comprises the following steps: dissolving cesium chloride, sodium chloride, lithium chloride and bismuth chloride in hydrochloric acid and stirring uniformly; placing the mixture into a reaction kettle to perform hydrothermal reaction; after the reaction is completed, centrifuging, washing and drying are performed to obtain Cs2Na 1‑ x Li x BiCl6, wherein x is 0.1-0.5. The lithium-doped cesium-sodium-bismuth-chlorine double perovskite photocatalyst has stronger photocatalytic reduction capacity, and can greatly improve the activity of the lithium-doped cesium-sodium-bismuth-chlorine double perovskite in photocatalytic reduction of carbon dioxide, and the generation rate of carbon monoxide can reach 10.25 mu mol per hour ‑1 ·g ‑1 .

The present invention relates to the technical field of lithium battery materials, and specifically discloses a lithium cobaltate doped nickel cobalt manganese ternary cathode material, a preparation method thereof and an application. The preparation method comprises the following steps: mixing lithium cobaltate, nickel cobalt manganese ternary precursors with at least two different particle size distributions, lithium carbonate and a first dopant, sintering, and crushing to obtain a first-sintered product; mixing the first-sintered product with a first surface coating material, sintering, and crushing to obtain a second-sintered product; mixing the second-sintered product with a second surface coating material, sintering, and crushing to obtain the lithium cobaltate doped nickel cobalt manganese ternary cathode material. By means of the first-sintering process, the present invention uniformly dopes the lithium cobaltate material into the nickel cobalt manganese ternary cathode material, effectively protects the layered structure of the nickel cobalt manganese ternary cathode material, reduces the mixing of nickel and lithium ions, and improves the cycle stability and safety performance of the material.

The invention relates to the technical field of lithium ion battery positive electrode materials, and particularly discloses a positive electrode lithium supplement agent and a preparation method and application thereof. The positive electrode lithium supplementing agent is of a core-shell structure, an inner core is doped lithium-rich lithium cobalt oxide, an outer shell is spinel lithium cobalt oxide, and the doped lithium-rich lithium cobalt oxide is specifically Li6CoO4 doped with Al, Mg and Zr; the preparation method comprises the following steps: preparing and uniformly mixing an aluminum source, a magnesium source, a zirconium source, a lithium source and a cobalt source according to a specific stoichiometric ratio, and then carrying out high-temperature solid-phase sintering and crushing in an inert atmosphere; preparing and uniformly mixing the one-step product, a cobalt source and a lithium source according to a specific stoichiometric ratio, and then carrying out low-temperature solid-phase sintering in an inert atmosphere; and crushing and sieving. The preparation method of the positive electrode lithium supplementing agent is suitable for large-scale and industrial production, and after the positive electrode lithium supplementing agent is applied to a high-voltage lithium cobalt oxide positive electrode and forms a battery cell with a silicon-based negative electrode, the battery cell has smaller gas production rate and better cycling stability, and the first-week irreversible capacity loss of the silicon-based negative electrode is effectively compensated.

The invention discloses a modified porous carbon composite material and a preparation method thereof, and the preparation method comprises the following steps: adding porous carbon and a heteroatom compound into a silver salt solution, and carrying out a hydrothermal reaction to obtain silver salt / heteroatom compound doped porous carbon; and depositing lithium salt in the silver salt / heteroatom compound doped porous carbon through an electrochemical deposition method, carbonizing and activating to obtain the modified porous carbon composite material. The obtained material utilizes silver doping and lithium doping to improve the electronic and ionic conductivity of the porous carbon material, reduces defects, improves the first efficiency and diffusion coefficient thereof, and is applied to the silicon carbon material to improve the rate capability and the first efficiency thereof.

The present invention discloses a high-rate and high-nickel cobalt-free cathode material, a preparation method thereof, and an application thereof. The chemical formula of the cathode material is LiNi x Mn 1‑x‑y‑z M y N z O2, M is one or more of Al, Zr, Y, W, Nb, Ce, Ti, Mg, Sr, B, P or Si, N is an MBene material coating layer, 0.5

The present invention relates to a nickel monoxide as a hole-conducting material and a perovskite solar cell containing the hole-conducting material as a hole-conducting layer, as well as a method for producing the nickel monoxide. The hole-conducting nickel monoxide (NiO) according to the invention x The composition is characterized by the addition of magnesium or of magnesium and lithium together as dopants. The mole fractions of the dopants are in the range of 2% to 4% for magnesium alone and 2% to 4% for magnesium together with 0.75% to 1.25% for lithium, and in particular 2.5% to 3.5% for magnesium and 0.9% to 1.1% for lithium. The NiO doped according to the invention x is of increased stability. A perovskite solar cell, which consists of a NiO doped with magnesium and lithium. xThe inventive method for producing a NiO-doped layer, comprising a hole-conducting layer, exhibits increased stability and improved efficiency. x is based on spray pyolysis in an oxidizing atmosphere. In the process according to the invention, the applied layer is doped with NiO. x First annealed and then cooled, after which further processing or storage is possible.

The application belongs to the technical field of refractory materials, and provides a tundish castable and a preparation method thereof.The tundish castable comprises the following components in parts by weight: bauxite clinker 54-57 parts, coke 23.5-25 parts, kyanite powder 3.8-4.2 parts, alpha-alumina micropowder 3-3.2 parts, high-aluminum cement 4.7-5.2 parts, silica ash 6.8-7.3 parts and lithium-doped magnesium oxide nano powder 2.7-3 parts.The application increases the amount / content of silica ash, reduces the apparent porosity of the prepared sample after 1400 DEG C heat treatment, and further improves the strength.

The invention belongs to the technical field of partial discharge ultraviolet detection, and particularly relates to a nickel oxide / zinc gallate heterojunction solar-blind ultraviolet photoelectric detector and application thereof. The invention discloses a nickel oxide / zinc gallate heterojunction solar-blind ultraviolet photoelectric detector, and the detector comprises an aluminum oxide substrate; the zinc gallate epitaxial layer grows on the aluminum oxide substrate through metal organic chemical vapor deposition; the lithium-doped p-type nickel oxide layer grows on the zinc gallate epitaxial layer through a pulse laser deposition technology; and the titanium / gold metal electrode layer is deposited on the lithium-doped p-type nickel oxide layer. The device has a high rectification ratio of 106, an ultralow dark current of 0.1 pA under a bias voltage of 6V, an excellent detection rate of 7.1 * 10 < 18 > Jones and an extremely low noise equivalent power of 2.56 * 10 <-19 > W / Hz < 1 / 2 >, so that the device becomes an ideal candidate material for partial discharge detection, security monitoring, environmental monitoring, space exploration and other applications.

The invention discloses an oxygen vacancy enriched lithium-doped zinc oxide nanotube reinforced polyethylene oxide (PEO)-based solid electrolyte and a preparation method thereof. The electrolyte takes PEO as a polymer matrix, lithium bis (trifluoromethanesulfonimide) (LiTFSI) as a lithium salt, and a three-dimensional hollow ZnO nanotube (LZN) doped with a lithium element as an inorganic reinforcing filler. By introducing Li < + > into ZnO crystal lattices for doping, a large number of positively charged oxygen vacancies can be induced to form, and the oxygen vacancies as Lewis acid sites have strong interaction with lithium salt anions to promote dissociation of lithium salt, so that the free Li concentration and ion mobility in the system are improved. The three-dimensional interconnection structure of the hollow nanotube constructs a continuous organic-inorganic ion transmission channel at the same time, so that the interface impedance is further reduced, and the overall ionic conductivity of the electrolyte is improved. The Li < + > conductivity of the prepared composite solid electrolyte at 60 DEG C can reach 8.12 * 10 <-4 > S / cm, and the composite solid electrolyte has excellent electrochemical stability and high coulombic efficiency. LiFePO4 / Li and NCM622 / Li all-solid-state batteries assembled by using the electrolyte membrane show good cycling stability and high-voltage adaptability. Through collaborative design of oxygen vacancy engineering and a hollow structure, the comprehensive performance of the polymer electrolyte is remarkably improved, and a new solution is provided for development of a high-energy-density and long-service-life all-solid-state lithium battery.

The present invention relates to expanded carbon for improving the output of a secondary battery and a method for manufacturing the same. The present invention comprises a method for manufacturing expanded carbon for enhancing the output of a secondary battery, wherein the method comprises the steps of: mixing lithium metal into a water-soluble oil and then mixing carbon to produce a mixture; reacting the mixture at 200 to 450°C while applying pressure to produce a lithium-carbon compound in which lithium is incorporated between carbon layers; and heat-treating the lithium-carbon compound to produce expanded carbon in which lithium is detached and removed from the lithium-carbon compound, thereby expanding the carbon layers; wherein the heat treatment is characterized by rapidly heating the lithium-carbon compound to 450 to 1,000°C by passing an electric current through it. The technical gist of the invention is the expanded carbon produced thereby.

The present invention provides a layered oxide with a mixed-phase structure, its preparation method, and its application, belonging to the technical field of sodium-ion battery positive electrode materials. This invention coats an O3 phase material with a layer of P2 phase material. This coating structure combines a high-capacity core O3 phase with a structurally stable outer P2 phase, improving the material's reversibility and air stability, reducing surface residual alkali, and improving rate performance. Furthermore, this invention eliminates the need for lithium doping to control the formation of the composite phase, reducing production costs.

The application discloses an organic superlattice material, a lithium-doped organic superlattice material and a preparation method and application thereof, and relates to the technical field of superlattice materials.The organic superlattice material comprises a first organic crystal layer and a second organic crystal layer which are alternately stacked, the first organic crystal layer comprises a network structure formed by a first small-molecule organic compound, and the second organic crystal layer comprises a network structure formed by a second small-molecule organic compound; wherein the first small-molecule organic compound comprises a first monocyclic aromatic compound, and the first monocyclic aromatic compound has a proton donor group; and the second small-molecule organic compound comprises a second monocyclic aromatic compound, and the second monocyclic aromatic compound has a proton acceptor group.A new organic superlattice material is provided, which is applied to a solid-state electrolyte and can improve ionic conductivity.

The present invention belongs to the technical field of laser inertial confinement fusion (ICF), and specifically relates to a hollow glass microsphere, a preparation method and application thereof. In order to meet the requirements of the ICF field, the present invention provides a preparation method for millimeter-scale thin-walled hollow glass microspheres, comprising depositing a lithium-doped silicon-containing polymer coating on the surface of a polymer microsphere by chemical vapor deposition, and then removing the inner layer of polymer microspheres by high-temperature degradation under an inert gas to obtain lithium-doped silicon-containing polymer hollow microspheres; then oxidizing them to lithium-doped glass microspheres, and densifying and sintering them at 1000-1100°C, then reducing them to 350°C at a rate of 0.1-1°C / min, and then cooling them to room temperature with the furnace. The present invention realizes the preparation of hollow glass microspheres with high geometric symmetry, low surface roughness, high gas retention and pressure resistance, with a diameter of millimeter scale and a wall thickness of micrometer scale. The prepared hollow glass microspheres have potential application prospects in the field of ICF.

The invention relates to the technical field of sodium-ion batteries, in particular to a P2-type layered metal oxide positive electrode material and application thereof in a sodium-ion battery. A conventional P2-phase positive electrode material Na < 0.67 > Mn < 0.5 > Ni < 0.5 > O < 2 > is poor in rate capability and rapid in cyclic discharge capacity attenuation. In order to solve the technical problems, the invention provides the P2 type layered metal oxide positive electrode material, the chemical composition of the P2 type layered metal oxide positive electrode material is Na < 0.67 > Mn < 0.5 > Ni < 0.2 > Li < 0.15 > Zn < 0.15 > O2, and the problems of low reversible specific capacity and poor rate capability of the Na < 0.67 > Mn < 0.5 > Ni < 0.5 > O2 positive electrode material are solved through co-doping of lithium and zinc. The lithium doping enhances the chemical bond between the transition metal and oxygen in the P2-type layered metal oxide, inhibits the migration and dissolution of transition metal ions, and improves the electrochemical stability of the positive electrode material. Zinc doping activates the oxidation-reduction activity of transition metal ions, and the specific discharge capacity of the positive electrode material is improved.

The application belongs to the technical field of lithium batteries, and relates to a preparation method of a double-coated silicon-carbon composite material, an electrode and a lithium battery.The method comprises the following steps: placing a lithium dopant and a MOF material in a first organic solvent, adding a template agent and a catalyst, reacting, filtering, freeze-drying and obtaining a gel composite; in an inert atmosphere, the gel composite is heated to a first preset temperature, carbon dioxide is introduced at a preset flow rate, the temperature is lowered, the gel composite is soaked in mixed acid, pickling is performed, vacuum drying is performed, and a porous carbon composite material is obtained; liquid silane, a phosphine derivative, a dispersing agent, the porous carbon composite material and a silane coupling agent are added to a second organic solvent, spray drying is performed, primary carbonization is performed, and a silicon-carbon precursor material is obtained; resin is dissolved in a third organic solvent, a fast ion conductor and the silicon-carbon precursor material are added, secondary carbonization is performed, the temperature is lowered to a second preset temperature, a reducing gas is introduced, and a double-coated silicon-carbon composite material is obtained; the conductivity is improved, the interface stability is improved, and the full charge swelling is reduced.

The invention provides a microwave-rheological phase coupling preparation method of a high-uniformity lithium manganese iron phosphate precursor. The microwave-rheological phase coupling preparation method comprises the following steps: (1) preparing a uniformly nucleated Mn < 2 + > / Fe < 2 + > precursor by using a microwave-assisted coprecipitation method; (2) adding the Mn < 2 + > / Fe < 2 + > precursor, lithium dihydrogen phosphate and a doping system into a rheological medium in proportion, and constructing a phosphorization and multi-element doped non-Newtonian fluid reaction environment in a rheological phase medium to obtain a pasty precursor compound; and (3) performing low-temperature crystallization and synchronous carbon coating on the pasty precursor compound under a first preset condition to obtain the carbon-coated lithium iron manganese phosphate precursor. The method comprises the following steps: firstly, inducing ions to instantaneously and uniformly nucleate by utilizing a microwave field, and solving the problem of fractional precipitation of Mn / Fe; then, a non-Newtonian fluid reaction environment is constructed, and atomic-scale mixing and morphology directional regulation and control are achieved; a lattice stabilizer and an oxygen vacancy regulating agent are synchronously introduced, so that the structural stability is improved.

The invention relates to the technical field of battery positive electrode materials, in particular to a layered P2-phase sodium-ion battery positive electrode material, a preparation method and a sodium-ion battery. The chemical general formula of the layered P2-phase sodium ion battery positive electrode material is Na < 0.8 > Li < 0.2 > Mg < 0.05 > Mn < 0.95-x > O < 2 >. The preparation method of the positive electrode material comprises the following steps: performing ball-milling compounding on sodium salt, lithium salt and metal oxide to prepare a precursor; the metal oxide is manganese dioxide; and tabletting the precursor, and calcining at the temperature of 900 DEG C + / -50 DEG C in an air atmosphere to prepare the layered P2-phase sodium-ion battery positive electrode material. According to the invention, through lithium doping, oxidation reduction of layered oxide positive electrode anions is excited, ultrahigh energy density is realized, the capacity retention ratio of the high-energy-density positive electrode can be improved, and the problem of voltage attenuation can be inhibited, so that the energy density of the high-energy-density positive electrode can be effectively maintained.

An ultrathin lithium-doped copper foil composite strip, its preparation method, and its applications are disclosed. This ultrathin lithium-doped copper foil composite strip exhibits high interfacial bonding strength between metallic lithium and the copper foil substrate. The dopant elements in the copper foil undergo rearrangement and segregation on the copper foil substrate surface, self-regulating the nucleation sites for metallic lithium deposition, achieving uniform nucleation and deposition of metallic lithium, and effectively suppressing lithium dendrite growth. Furthermore, the addition of dopant elements to the copper foil not only refines the grain size and increases the toughness of the copper substrate, thus enabling the preparation of thinner copper current collectors, but also reduces the copper content in the current collector, thereby lowering the current collector cost.

This invention discloses a Schottky diode based on cubic boron nitride (c-BN) single crystal material. The fabrication method includes the following steps: A cleaned bulk c-BN single crystal is covered with tape, exposing only the area to be plated with electrodes. An Au metal electrode is deposited on one side of the bulk c-BN single crystal, and then the tape is removed. In a glove box, the oxide layer on the surface of a lithium sheet is scraped off, and the sheet is placed on the Ag-plated side of a PCB board. The unplated side of the bulk c-BN single crystal is then tightly attached to the lithium sheet. Fine metal wires are used to connect and fix the Ag electrode on the PCB board to the Au electrode on the bulk c-BN single crystal. After electrochemical doping, an Au metal electrode is deposited on the lithium-doped side of the c-BN crystal. In this invention, lithium atoms are introduced onto the c-BN surface, and their energy levels are located at shallow levels, thereby effectively improving the interfacial contact quality between the metal and c-BN. This improvement further reduces the contact barrier ΦB between the c-BN single crystal and the metal by reducing the interfacial state density.

The application discloses a preparation method of a double-layer coated silicon-carbon composite material, which comprises the following steps: uniformly mixing acid-based resin and organic alkali-based pore-forming agent, then adding the mixture into lithium carboxymethyl cellulose, uniformly dispersing, spray drying, transferring the obtained material into a tube furnace for carbonization, naturally cooling to room temperature, and obtaining lithium-doped porous carbon; adding niobium salt and titanium salt into liquid silane to prepare a 1-10wt% solution in an organic solvent, uniformly dispersing, then adding the lithium-doped porous carbon, uniformly dispersing, spray drying, transferring into a tube furnace for sintering, obtaining titanium niobate coated silicon-carbon composite material, transferring into a tube furnace, and depositing amorphous carbon on the surface of the titanium niobate coated silicon-carbon composite material, thereby obtaining the titanium niobate coated silicon-carbon composite material. The material obtained by the application can improve the initial efficiency, fast charging performance and reduce the expansion.