Abstract: A carbon coated composite includes a core and a carbon coating layer coated outside the core. The density of the carbon coating layer is 1.0 g·cm?3??2?2.0 g·cm?3. The dissolution amount of a core characteristic element of the carbon coated composite is 100 ppm or less. The D50 of the material to be coated with carbon is 1-40 ?m. The particle size distribution span meets 0.5?(D90?D10)/D50?2. A specific surface area is 1-5 m2·g?1. A ratio of the specific surface area to the stacked pore volume is 0.5-2 cm?1. The increase of D50 of the composite after coating is 3 ?m or less. The shell of the carbon coated composite mitigates the volume change of the core. A complete and uniform carbon layer effectively disperses surface charges to form a more stable electric double layer structure.

Abstract: A modified silicon monoxide material is used for a negative electrode of a lithium battery, and is prepared by reacting raw materials of silicon, silicon dioxide and metal silicate under high-temperature and vacuum conditions to prepare silicon monoxide; and meanwhile, reacting the metal vapor with silicon monoxide in the preparation process to in situ form metal silicate. In the modified silicon monoxide material, the metal silicate is uniformly dispersed around the silicon and the silicon monoxide to form silicon-containing particles, and a carbon material coats the surfaces of the silicon-containing particles.

Abstract: A preparation method of silicon-based composite negative electrode material for a lithium battery includes the following steps: forming steam from a raw material A containing Si and a reducing substance raw material B capable of reacting to generate a silicate under a vacuum heating condition, condensing and depositing in a deposition system after a reaction, and then carrying out carbon coating to obtain the silicon-based composite material. A certain amount of alloy is added into the raw material B, so that a proportion of a crystal region in the silicon-based composite material can be reduced, and the initial coulombic efficiency and the cycling stability of the negative electrode material are further improved.

Abstract: A preparation method of silicon-based composite negative electrode material for a lithium battery includes the following steps: forming steam from a raw material A containing Si and a reducing substance raw material B capable of reacting to generate a silicate under a vacuum heating condition, condensing and depositing in a deposition system after a reaction, and then carrying out carbon coating to obtain the silicon-based composite material. A certain amount of alloy is added into the raw material B, so that a proportion of a crystal region in the silicon-based composite material can be reduced, and the initial coulombic efficiency and the cycling stability of the negative electrode material are further improved.

Abstract: A modified silicon monoxide material is used for a negative electrode of a lithium battery, and is prepared by reacting raw materials of silicon, silicon dioxide and metal silicate under high-temperature and vacuum conditions to prepare silicon monoxide; and meanwhile, reacting the metal vapor with silicon monoxide in the preparation process to in situ form metal silicate. In the modified silicon monoxide material, the metal silicate is uniformly dispersed around the silicon and the silicon monoxide to form silicon-containing particles, and a carbon material coats the surfaces of the silicon-containing particles.