▎ 摘　　要

NOVELTY - Preparing silicon negative electrode coated with polymer polyurea coating, involves using silicon material or silicon carbon material as the active material of the silicon-based negative electrode, and adding a binder and a conductive agent to prepare an electrode. The electrode is put into the molecular layer deposition chamber at 30-100℃, where inert gas is used as the carrier gas, the carrier gas flow rate is set at 10-200 standard cubic centimeters per minute, and the preheating temperature of isocyanate precursor is 50-110℃, the pulse time is 0.2-1 second, and the purge time is 20-50 second. The preheating temperature of the amino compound precursor is 20-60℃, the pulse time is 0.2-1 second, and the purge time is 20-50 second. The cycle period of atomic layer deposition is set as M, which is between 5-100 cycles. USE - Method for preparing silicon negative electrode coated with polymer polyurea coating for improving long-term stable cycle life of silicon-based negative electrode, where stable cycle life refers to the severe volume expansion of the buffer silicon, which promotes the formation of a stable interface and improves the retention of the cycle capacity (claimed). ADVANTAGE - The preparation method is simple and the repeatability good. The polyurea coating significantly buffers the volume expansion of the silicon particles, improves the compatibility between the silicon and the electrolyte, and also improves the stability of the interface, so that the silicon negative electrode has excellent cycle stability and multiplying power performance. DETAILED DESCRIPTION - Preparing silicon negative electrode coated with polymer polyurea coating, involves using silicon material or silicon carbon material as the active material of the silicon-based negative electrode, and adding a binder and a conductive agent to prepare an electrode. The electrode is put into the molecular layer deposition chamber at 30-100℃, where inert gas is used as the carrier gas, the carrier gas flow rate is set at 10-200 standard cubic centimeters per minute, and the preheating temperature of isocyanate precursor is 50-110℃, the pulse time is 0.2-1 second, and the purge time is 20-50 second. The preheating temperature of the amino compound precursor is 20-60℃, the pulse time is 0.2-1 second, and the purge time is 20-50 second. The cycle period of atomic layer deposition is set as M, which is between 5-100 cycles. The prepared electrodes are dried in a vacuum box, and used liquid electrolyte to assemble the battery. Preferably, the silicon material or silicon carbon material is put into the molecular layer deposition chamber at 30-100℃, used the inert gas as the carrier gas, and set the carrier gas flow at 10-200 standard cubic centimeters per minute. The polyurea-coated silicon material or silicon carbon material is used as an active material, added a binder and a conductive agent to prepare an electrode, where binder includes polyvinylidene fluoride, styrene-butadiene rubber emulsion, sodium carboxymethyl cellulose in dosage of 0.5-15 wt.%, and the conductive agent includes conductive carbon black, acetylene black, and carbon fiber in dosage of 0.5-15 wt.%. The prepared electrodes are dried in a vacuum box, and used liquid electrolyte to assemble a battery.