Vanadium-antimony co-doped lithium iron phosphate used as lithium ion positive pole material and preparation method thereof

Abstract

The invention provides a vanadium-antimony co-doped lithium iron phosphate used as the lithium ion positive pole material and a preparation method thereof. According to the vanadium-antimony co-doped lithium iron phosphate used as the lithium ion positive pole material and the production method thereof, a lithium source, an iron source, a phosphate source and a dopant are weighed according to the mol ratio of Li+:iron ion:Sb3+:V5+:PO43-=(1-1.05):(1-x-y):x:y:(1-1.02), a carbon source and a mixed medium are added, a liquid phase is adopted for mixing the materials to obtain submicron slurry; the slurry is dried, put in the carbon coating reducing atmosphere, directly heated to 650-750 DEG C for sintering and insulated for 3-12 hours; and then the slurry is cooled naturally to the room temperature to obtain the vanadium-antimony co-doped lithium iron phosphate material, and the general chemical formula of the lithium iron phosphate is LiFe1-x-ySbxVy(PO4) / C, wherein 0.002=>x<=0.01, 0.01=>y<=0.02, and 0.012=>x+y<=0.03. The lithium iron phosphate prepared according to the invention has the advantages that electrochemical properties are excellent, the electronic and ion conductivity of the lithium iron phosphate are improved, the specific capacity and the high-rate discharge property of the lithium iron phosphate are improved, so that the specific energy and the specific power of the lithium iron phosphate as the power battery are improved, the energy density and the power properties of the lithium iron phosphate material are improved to a high level, and the manufacture cost is remarkably reduced.

Description

technical field [0001] The invention relates to a lithium ion positive electrode material vanadium and antimony co-doped lithium iron phosphate and a preparation method thereof. The material is used as a positive electrode active material of a lithium ion battery and has the characteristics of high energy density and high power performance. It will be used in electric vehicles in the future. and other new energy fields have potential application value. Background technique [0002] In today's era when energy conservation and environmental protection are on the agenda, lithium-ion batteries are a kind of green energy that meets the low-carbon economy. It has the advantages of high specific capacity, high discharge voltage, good cycle performance, low self-discharge rate, and no memory effect. Cathode material is a key part that determines the performance of lithium-ion batteries. Research and development of high-performance cathode materials is the key to the development of l...

AI Technical Summary

Problems solved by technology

Although the above-mentioned preparation method is simple in process and easy to control, it is beneficial to industrial production, but the product has disadvantages such as poor electrochemical performance, wide particle size distribution, and low tap density, resulting in low volumetric energy density and poor rate performance, making the material Practical application value is greatly reduced

In order to improve the performance of lithium iron phosphate, the traditional single doping scheme can no longer achieve the expected purpose. For example, although a single vanadium doping can significantly improve the electrochemical discharge platform, it cannot improve the bulk transport rate of lithium ions very well. Its rate performance is limited; and a single antimony doping can effectively improve the particle size distribution and increase the vibration, but the reduction and precipitation of trace metal antimony will increase the self-discharge

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