Preparation method of nitrogen and phosphorus co-doped silicon monoxide negative electrode material, negative electrode material, negative electrode plate and lithium battery

The invention discloses a preparation method of a nitrogen-phosphorus co-doped silicon monoxide negative electrode material, the negative electrode material, a negative electrode plate and a lithium battery, and belongs to the technical field of lithium ion battery electrode materials. Ammonium dihydrogen phosphate or ammonium phosphate is used as a nitrogen source and a phosphorus source, asphalt is used as a carbon source, water is used as a solvent and a dispersing agent, and the nitrogen and phosphorus co-doped silicon monoxide long-circulation negative electrode material is prepared through simple mixing, drying and carbonization treatment. Nitrogen and phosphorus are co-doped in a silicon monoxide surface coating layer, so that the electronic conductivity and the lithium ion passing rate can be obviously improved, the internal resistance is reduced, the cycle performance is greatly improved, and the problems that a soft carbon coating layer formed by adopting a conventional solid-phase/gas-phase coating