A kind of preparation method of lithium iron phosphate electrode

Abstract

The invention belongs to the technical field of lithium ion batteries and particularly relates to a preparation method of a lithium iron phosphate electrode. The preparation method of the lithium iron phosphate electrode comprises the following steps of: scattering nanoscale lithium iron phosphate granules into an organic solvent, then carrying out secondary granulation on the nanoscale lithium iron phosphate granules in a spray drying mode so as to form lithium iron phosphate secondary granules with the median granule diameter of 4-5 microns; stirring a bonding agent and the lithium iron phosphate secondary granules for 0.1-3 hours in a dry mixing device; scattering a scattering agent and more than two electric conducting agents uniformly in N-methyl pyrrolidone or water so as to form a scattering solution; adding the mixture of lithium iron phosphate and a bonding agent into the scattering solution and carrying out ultrasonic wave scattering so as to form electrode slurry of a three-dimensional electric conduction network structure; uniformly coating the electrode slurry on an aluminum foil, and finally drying, thus obtaining the lithium iron phosphate electrode. Compared with the prior art, the preparation method provided by the invention has the advantage that the multiplying power performance, the low-temperature electric discharge performance, the capacity and energy density of a battery can be improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a preparation method of a lithium iron phosphate electrode. Background technique [0002] The traditional lithium iron phosphate electrode is mainly composed of a current collector and an electrode material layer attached to it. The current collector is aluminum, and the electrode material layer is mainly composed of an active material, a conductive additive and a binder. The preparation method is generally: Lithium, binder and conductive agent are all added to the organic solvent, and the electrode slurry is made after stirring evenly, and then the electrode slurry is coated on the aluminum foil by extrusion coating or transfer coating, and then dried and cooled. Lithium iron phosphate electrode was obtained. [0003] For lithium iron phosphate with a larger particle size (above micron level), the electrode is prepared by the above method, which can ma...

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Problems solved by technology

However, for nano-scale lithium iron phosphate materials, there are more nano-scale lithium iron phosphate particles than micron-sized lithium iron phosphate particles under the same weight, and it is more difficult to disperse, and the same amount of conductive agent (compared with the use of micron-sized lithium iron phosphate particles) The same amount of conductive agent used in the electrode prepared by lithium iron phosphate) cannot form a good conductive effect between nanoscale lithium iron phosphate particles, and increasing the amount of conductive agent will correspondingly reduce the amount of active material (ie lithium iron phosphate), As a result, the capacity density of lithium iron phosphate batteries is reduced

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