▎ 摘　　要

NOVELTY - Preparing a double-layer carbon-modified silicon cathode material, comprises (1) ultrasonically treating the silicon-based particles in an organic solvent, adding the silane coupling agent, heating and stirring, and centrifugally drying to obtain silicon-based A material modified by surface silane coupling agent, (2) dispersing A in organic solvent, dropping ionic liquid into dispersion, heating and stirring to obtain material B grafted with the ionic liquid, (3) dispersing material B and reduced graphene oxide (rGO) material in ethanol and ultrasonically mixing, heating and stirring, washing and drying product to obtain material C, (4) mixing material C with graphite for defoaming and stirring, calcining, and cooling to room temperature to obtain a double-layer carbon modification in which the first layer is strongly linked by rGO and silicon substrate, and coating the second layer is homogeneously with rGO by graphite carbon silicon anode material. USE - The method for preparing double-layer carbon-modified silicon cathode material useful in lithium ion battery electrode (claimed). ADVANTAGE - The method adopts ionic liquid, improves the volume expansion of the silicon anode material during the charge-discharge cycle, forms a continuously connected buffer layer to overcome the cracking of silicon particles while improving interfacial conductivity, improves the structural stability of negative active materials significantly, and long cycle life of materials. DETAILED DESCRIPTION - Preparing a double-layer carbon-modified silicon cathode material, comprises (1) ultrasonically treating the silicon-based particles in an organic solvent, adding the silane coupling agent to the above dispersion, heating and stirring, and centrifugally drying to obtain the silicon-based A material modified by the surface silane coupling agent, (2) dispersing A in an organic solvent, adding the ionic liquid dropwise to the dispersion, heating up and stirring to obtain the B material grafted with the ionic liquid, (3) dispersing the material B and the reduced graphene oxide (rGO) material in ethanol and ultrasonically mixing, and heating and stirring, and washing and drying the product to obtain material C, (4) mixing material C with graphite for defoaming and stirring, calcining with temperature control, and cooling to room temperature to obtain a double-layer carbon modification in which the first layer is strongly linked by rGO and silicon substrate, and coating the second layer is homogeneously with rGO by graphite carbon silicon anode material, and the ultrasonic time is 3-60 minutes; and the stirring time is 1-20 hours, and the stirring temperature is 40-120℃; in the step (3), rGO is a doping material, and the doping elements include boron, nitrogen, phsophorus, sulfur, chlorine, bromine and/or fluorine; the step (4) defoaming stirring time is 0.1-5 hours, and the rotating speed is 200-10000 revolutions/minute; the structure of the silane coupling agent added in the step (1) is that R is a non-hydrolyzable group including methyl, ethyl, propyl, mercapto, mercaptoethyl, mercaptopropyl, vinyl, propenyl, amino, aminoethyl, aminopropyl, epoxy, cyano, haloalkyl, acryloyloxy and/or glycidyloxypropyl; X is hydrolyzable groups including halogen, acyloxy group, alkoxy group, aryloxy group and acyl group; and the addition amount is 0.1-10 wt.%. An INDEPENDENT CLAIM is included for a modification method to obtain an internal interface-connected composite silicon-carbon cathode material of double-layer carbon-coated modified silicon-based particles. DESCRIPTION OF DRAWING(S) - The drawing shows a double-layer carbon-coated silicon-based composite material cathode schematic diagram (Drawing includes non-English language text).