Preparation method for iron phosphate used for lithium battery

Abstract

The invention discloses a preparation method for iron phosphate used for a lithium battery. The iron phosphate comprises a secondary particles aggregated by a plurality of primary particles, wherein each primary particle is of a hollow porous spherical structure; and the secondary particle is of a hollow porous sphere-like structure. According to a scheme of the invention, the iron phosphate is ofa unique hollow porous sphere-like structure; lithium iron phosphate prepared by taking the iron phosphate as a precursor has a porous structure; the contact area of an electrolyte and a positive electrode material is increased; good wettability is achieved; meanwhile, the porous structure also has the advantages of reducing ion diffusion resistance and the like; through the hollow structure, thediffusion path of lithium ions is shortened; meanwhile, a plurality of paths are provided for diffusion of the lithium ions; the problems of low diffusion speed, polarization and the like of a lithium iron phosphate material in the prior art are solved; and thus, the lithium iron phosphate with good performance, specifically good low-temperature performance, can be prepared by using the lithium iron phosphate as the precursor.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a method for preparing iron phosphate for lithium batteries. Background technique [0002] A lithium-ion battery is a secondary battery (rechargeable battery) that operates primarily by moving lithium ions between positive and negative electrodes. During the charging and discharging process, Li + Intercalation and deintercalation back and forth between two electrodes: when charged, Li + It is deintercalated from the positive electrode, inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge. In recent years, with the global support for new energy vehicles, lithium-ion batteries have developed rapidly. [0003] The positive electrode material is one of the key materials that determine the performance of lithium-ion batteries, and is also the main source of lithium ions i...

AI Technical Summary

Problems solved by technology

Lithium cobalt oxide battery is suitable for small batteries, its actual capacity is not high, and the material contains highly toxic cobalt element, not only the price is high, but also it is difficult to guarantee its safety when making large power batteries

Lithium manganese oxide battery has good low temperature resistance and rate performance, but it has defects such as poor stability of the material itself and poor cycle performance.

Although the ternary materials nickel-cobalt lithium manganate and nickel-cobalt lithium aluminate have high energy density, they also contain cobalt, so they also have similar defects to lithium cobalt oxide batteries.

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