▎ 摘　　要

NOVELTY - Preparation of silicon carbene material involves (1) weighing pure graphite, doping with metal gallium powder, pouring into acetone solution, stirring in vacuum stirrer, extracting acetone to partly evaporate, pressing into graphite boat, preparing as a target, placing the sample boat into stainless steel shell reaction chamber, generating enhanced plasma in this chamber, (2) vacuuming to 10-4 mTorr, (3) heating, (4) turning on femtosecond laser, bombarding the mixture of graphene quantum well crystal nuclei or quantum dots and high hydrogen-diluted silane plasma, (5) turning on the high-frequency bias voltage in the reaction chamber, (6) forming graphene quantum dots and high hydrogen-diluted silane plasma by violent collisions between crystal nuclei, using gallium as a catalyst, generating a large silicon carbide unit layer or a three-layer silicon carbene with two silicon atomic layers, heating and collecting the products at the bottom of the reaction chamber. USE - Preparation of silicon carbene material for preparation of electrode and silicon carbene electrode active material for preparing battery and lithium-sodium alloy/silicon carbide unit-layer rechargeable battery (all claimed). ADVANTAGE - The method produces product which provides silicon carbene electrode active material with high specific energy and stable cycle characteristics. The silicon carbene electrode active material can improve the energy density and power density of lithium-sodium rechargeable batteries. DETAILED DESCRIPTION - Preparation of silicon carbene material involves (1) weighing pure graphite, doping with metal gallium powder, pouring into acetone solution, stirring in a vacuum stirrer, sealing and stirring for 24 hours, extracting acetone to partly evaporate, making the wet powder into a cake shape, pressing into graphite boat, preparing as a target, placing the sample boat into stainless steel shell reaction chamber with reactant nozzle that produces high hydrogen-diluted silane gas, forming strong electric field between the sample base and the inert gas nozzle at applied voltage of 2000-20000 V, (2) vacuuming to 10-4 mTorr, (3) heating the sample boat to 1200-1500 degrees C, (4) turning on the inert gas high-purity argon injection, aligning the target in the sample boat, maintaining the sputtering power at 90-200 W and working pressure at 0.5-2 mTorr, turning on the plasma generation switch, turning on high hydrogen dilute silane, controlling the volume ratio of silane and hydrogen at 1:20, injecting into the reaction chamber, covering with the sputtered graphene quantum dot gas in the exit space of 10-200 nm on the surface of the target, turning on the femtosecond laser, aiming femtosecond laser at the product produced by argon sputtering graphite in the sample boat-graphene nuclei or quantum dots and a high hydrogen-diluted silane plasma mixture, bombarding the mixture of graphene quantum well crystal nuclei or quantum dots and high hydrogen-diluted silane plasma, (5) turning on the high-frequency bias voltage in the reaction chamber to reach 2000 Hz to 100 MHz, superimposing on 1-15 Tesla superconducting static magnetic field, (6) forming graphene quantum dots and high hydrogen-diluted silane plasma by violent collisions between crystal nuclei, empowering by laser gun radiation, using gallium as a catalyst, generating a large silicon carbide unit layer or a three-layer silicon carbene with two silicon atomic layers sandwiching a carbon atomic layer or two carbon atomic layers, sandwiching a silicon atomic layer, reacting for 20-50 minutes, (7) turning off the laser power supply, high-purity argon switching power supply, plasma power supply and high-hydrogen-diluted silane switch in turn, heating the sample for 20 minutes, (8) turning off the heating power supply, naturally cooling the sample chamber to room temperature, opening the reaction chamber, taking out the sample boat, and collecting the products at the bottom of the reaction chamber. INDEPENDENT CLAIMS are included for the following: (1) silicon carbene prepared by the method, which has three basic structures (s1)-(s3). The structure (s1) of the silicon carbene is of formula: SiC. The structure (s2) of the silicon carbene is of formula: Si1-xCx, where x is 0.5-1 (excluding 0.5-1). The structure (s3) of the silicon carbene is of formula: SixC1-x; (2) method for making electrode, which involves placing silicon carbene material, polyvinylidene fluoride and graphene conductive agent, adding N-methyl-2-pyrrolidone, applying to foamed nickel, drying, cooling to room temperature, pressing into sheet, assembling with button cell, using lithium sheet as counter electrode, installing diaphragm, pouring lithium ion electrolyte and ethyl carbonate containing lithium hexafluorophosphate and sealing; (3) preparation of silicon carbene electrode active material, which involves weighing polysiloxane, sodium acetylene, starch and absolute ethanol, weighing the corresponding compounds and organic matter, adding into the beaker, stirring for 12 hours, drying at 160-200 degrees C for 10 hours, weighing micron-grade sorghum powder, sodium ethoxide and bismuth sorghum in molar ratio of 7-10:7-10:1-2:1-3:0.5-1 in beaker, adding ferrocene, 1,2-dimethyl-1,2-diphenyldisilene, urushiol formal lanthanum polymer and sodium dialkyl sulfonate in another beaker, adding deionized water, mixing, heating at 120-200 degrees C, mixing the two gel powders in the two beakers, stirring for 12 hours, feeding into crucible, vacuuming at 1-3 Pa, filling the atmosphere reactor with argon gas at 3-2.1 MPa, heating to 800-1300 degrees C at 20-30 degrees C/minute for 1-3 hours and cooling to room temperature; (4) silicon carbene electrode active material prepared by the method; (5) preparation of battery, which involves using the silicon carbene electrode active material, coupling with conductive agent and adhesive polyvinylidene fluoride according to ratio of silicon carbene, conductive agent carbon black and polyvinylidene fluoride is 60:20:20, adding N-methyl-2-pyrrolidone to dissolve, stirring, coating on copper foil of current collector, drying at 170 degrees C for 18 hours, compressing, cutting, placing together with counter electrode lithium sheet and diaphragm and adding electrolyte to assemble a button battery; and (6) lithium-sodium alloy/silicon carbide unit-layer rechargeable battery, which is prepared by using the silicon carbene active electrode material and counter electrode lithium-sodium alloy, electrolyte and diaphragm. The mass ratio of lithium and sodium is 100-20:0-80.