A kind of negative electrode active material, negative electrode sheet and its preparation method and lithium ion battery

Abstract

An active negative electrode material, a negative electrode pole piece, a preparation method thereof, and a lithium ion battery. Described negative electrode active material is the carbon material that the surface contains oxygen-containing organic functional group, or this carbon material and silicon or / and tin form by mechanical fusion one or at least two in carbon-silicon or / and carbon-tin composite material The combination. The negative electrode sheet comprising the active negative electrode material of the present invention can form a good compatibility with the electrolyte, and during the charging and discharging process, the oxygen-containing functional groups on the surface of the carbon material and the lithium salt and the solvent in the electrolyte can pass through carbon and oxygen. The chemical bonding action forms a dense and stable in-situ solid electrolyte membrane and a nano-scale microporous channel structure on the surface of the carbon material, so that the lithium-ion battery containing the negative electrode plate has low internal resistance, long cycle life and low liquid retention. Excellent rate capability.

Description

technical field [0001] The invention belongs to the field of lithium batteries. Specifically, the invention relates to a negative electrode active material, a negative electrode sheet, a preparation method thereof, and a lithium ion battery containing the negative electrode sheet. Background technique [0002] With the continuous development of the new energy industry, lithium-ion batteries, as a green and environmentally friendly new energy battery, have developed extremely rapidly. With the expansion of the application field of lithium batteries, people have put forward higher requirements for the energy density and safety performance of lithium batteries, and at the same time, the amount of electrolyte in the battery is also gradually reduced. [0003] However, there is a certain contradiction between the improvement of energy density and the reduction of liquid retention. In order to ensure the excellent comprehensive performance of high energy density lithium batteries,...

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Problems solved by technology

[0009] Although the above method can improve the stability of the SEI film of high-energy-density batteries to a certain extent, and improve the cycle performance of the battery within a certain range, it will increase the manufacturing cost of the battery, and the manufacturing process is complicated, which is not conducive to mass production. , in the case of less liquid retention, the actual improvement effect is not significant

[0010] At the same time, with the continuous development of smart mobile devices, after putting forward higher requirements for the energy density and liquid retention capacity of lithium batteries, new requirements are also put forward for their fast charging capabilities. However, the improvement of energy density and electrolyte retention The reduction of liquid volume will seriously affect the rate charge and discharge performance of lithium batteries, thus limiting its wide application in the field of fast charging

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