Method for preparing lithium iron phosphate having high tap density

Abstract

The invention discloses a method for preparing lithium iron phosphate having high tap density. The method for preparing lithium iron phosphate having high tap density is characterized in that on the basis of existing solid phase method preparation of lithium iron phosphate, a carbon source is reduced or not added at a precursor mixing phase so that the failure in sintering densification of lithium iron phosphate grains caused by coated carbon is avoided; at a high temperature area of a sintering phase, a front phase attaches importance to nitrogen atmosphere or weak reducing atmosphere protection, the coated carbon is deposited in a CVD method at a later phase, and accordingly lithium iron phosphate having high tap density is obtained. According to the method, sintering densification is performed first and then uniform carbon deposition is performed, and accordingly high-performance lithium iron phosphate having high tap density and uniformly coated with carbon is obtained. The method is improved based on existing industrialization and is easy to achieve.

Description

technical field [0001] The invention relates to the technical field of material preparation, in particular to a method for preparing lithium iron phosphate with high tap density. Background technique [0002] Lithium iron phosphate is one of the mainstream cathode materials in the current lithium-ion battery field, but its two shortcomings limit its application development: poor conductivity and low vibration. Among them, the problem of poor conductivity has been obviously solved by methods such as carbon coating and doping, but there has been no good solution to the problem of low vibration. The true density of lithium iron phosphate is 3.4, but the vibration of the actual industrial product can reach up to about 1.2. The volume energy density of lithium iron phosphate is not dominant, and the battery is bulky, which is not conducive to its development in the field of power energy. [0003] At present, the industrial production of lithium iron phosphate is mainly based on...

AI Technical Summary

Problems solved by technology

[0002] Lithium iron phosphate is one of the mainstream cathode materials in the field of lithium-ion batteries, but its two shortcomings limit its application development: poor conductivity and low vibration

Among them, the problem of poor conductivity has been obviously solved by methods such as carbon coating and doping, but there has been no good solution to the problem of low vibration

Therefore, there is a problem: the carbon layer has been coated before the sintering of lithium iron phosphate, so that the lithium iron phosphate cannot form a dense sintered body, and the obtained product is relatively fluffy and the tap density is not high.