High-concentration few-layer graphene composite material, component of lithium battery electrode and preparation

Abstract

The invention discloses a high-concentration few-layer graphene composite material, a component of a lithium battery electrode and preparation, belonging to the technical field of preparation of electrode materials. The preparation method disclosed by the invention comprises the following steps: firstly preparing expansion graphite, then mixing and stirring a dispersing agent, a liquid carrier, an anion type surface active agent and a defoaming agent to prepare mixed liquor, then adding the expansion graphite into the mixed liquor, performing cleavage through a high-shearing cleavage device to get high-concentration few-layer graphene, finally mixing with a binding agent and a lithium battery active material to form electrode slurry, and coating to prepare an electrode. The prepared graphene in the invention has the properties of high electric conduction, high thermal conductivity, high concentration and easiness in dispersion, the material is doped into positive and negative pole materials of a lithium battery for preparing pole pieces, the electron conductivity can be effectively increased, the internal resistance of the battery can be greatly reduced, the heat produced by the battery during charge and discharge can be reduced, and the power density, the energy density, the safety and the cycle life of the battery can be further upgraded.

Description

technical field [0001] The invention belongs to the technical field of electrode material preparation, and specifically relates to the composition and preparation of a high-concentration few-layer graphene composite material and a lithium battery electrode. Background technique [0002] Lithium batteries are accompanied by the transmission of lithium ions and the migration of electrons during the reaction process of charging and discharging. Therefore, the conductive additives in the electrodes need to have good conductivity and a large diameter-to-thickness ratio (aspect ratio) to ensure the formation of a good conductive network. , and thus has a lower electrode resistivity, on the other hand, it needs to have good interfacial contact with the active material and the current collector to ensure the integrity and continuity of the conductive network during the cycle, and the conductive additive with the above two characteristics can be Make the electrode active material hav...

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Problems solved by technology

[0005] Although most studies believe that there is only van der Waals force between graphite sheets, and only a small theoretical energy (about 17 kJ / mol) can be used to peel off graphite sheets to form graphene, but in fact there are Different degrees of structural defects, even carbon-carbon bonding, cause the energy required to peel off the graphite layer to be much greater than the theoretical value, so a small shear energy cannot completely cleave the graphite sheet, and the shear energy must be greatly increased to ensure Cleavage of most graphite flakes to obtain thinner graphene

[0006] In addition, although graphene has excellent electrical conductivity, it has the disadvantage of easy folding back, especially in the process of drying graphene suspension into powder, the folding back phenomenon between graphene sheets is more serious, Once the graphene folds back, it is not easy to disperse, and the conductivity will be greatly reduced

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