Silicon-carbon negative electrode material, silicon-carbon negative electrode, lithium-ion battery and electric vehicle

Abstract

The invention discloses a silicon-carbon negative electrode material, a silicon-carbon negative electrode, a lithium-ion battery and an electric vehicle and relates to the technical field of lithium-ion batteries. The silicon-carbon negative electrode material comprises a silicon-carbon negative electrode active material, conductive agents and a binder, wherein the conductive agents are conductivecarbon black and a single-walled carbon nanotube. The conductive carbon black and the single-walled carbon nanotube are adopted as the conductive agents, so that expansion of the electrode is greatlyinhibited and the electric property of the battery is improved. A preferred lithium-ion battery system comprises a negative electrode and a positive electrode; the silicon-carbon negative electrode material is adopted by the negative electrode; lithium nickel cobalt manganese oxide or lithium nickel cobalt aluminum oxide of which the nickel content is greater than or equal to 60% is adopted by the positive electrode; and an electrolyte organic solvent is prepared by mixing fluoroethylene carbonate with ethylene carbonate, diethyl carbonate and methyl ethyl carbonate at a certain ratio. The battery is high in energy density and good in cycle performance.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a silicon-carbon negative electrode material, a silicon-carbon negative electrode, a lithium-ion battery and an electric vehicle. Background technique [0002] Power battery technology is one of the key factors restricting the development of the new energy vehicle industry. Improving the energy density and cycle life of power batteries is an urgent need for the development of new energy vehicles. High-performance cathode and anode materials are the key basis for achieving energy density goals. For high-capacity and high-performance material systems, high-nickel cathode materials with high specific capacity, low cost, and long life are currently research hotspots at home and abroad, and are considered to be extremely promising cathode materials for lithium-ion power batteries. The current negative electrode materials are mostly graphite materials. During the theoret...

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Problems solved by technology

Silicon carbon material is a typical silicon-based material. However, the volume expansion of silicon carbon negative electrode material is about 100% to 300% in the process of charging and discharging, while that of graphite material is only about 10%. Therefore, the expansion and contraction of silicon carbon negative electrode will cause negative electrode material The pulverization of the battery will seriously affect the cycle stability and service life of the battery

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