Lithium iron phosphate cathode material and preparation method thereof

A technology for lithium iron phosphate and positive electrode materials, applied in chemical instruments and methods, phosphorus compounds, battery electrodes, etc., can solve the problems of difficult control of metal powder uniform distribution, complicated process, high cost, etc., and achieve strong complementarity between large and small particles, production The effect of simple process and low equipment requirements
CN101559935AInactive Publication Date: 2009-10-21SOUTH CHINA UNIV OF TECH
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
SOUTH CHINA UNIV OF TECH
Publication Date
2009-10-21
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a lithium iron phosphate cathode material and a preparation method thereof. The cathode material comprises 30-450nm of small particle size lithium iron phosphate accounting for 25-50% of the total volume, 450-3000nm of large particle size lithium iron phosphate accounting for 50-75% of the total volume and conductive carbon. In the preparation, lithium phosphate and iron phosphate are firstly prepared; then, the lithium phosphate and the iron phosphate are mixed according to the mol ratio of 2 / 3-2:1 and then added with phosphorus source compound, ferric iron source compound and lithium source compound; afterwards, absolute ethyl alcohol is added into the mixture for ball milling, and the lithium iron phosphate cathode material is obtained after the processing. The invention adopts a coprecipitation method to prepare the spherical iron phosphate and lithium phosphate which have controllable particle sizes, and then uses a solid state sintered technology to synthesize the lithium iron phosphate, so that the tap density reaches 1.6g / cm; the source of the raw materials is wide, and the requirements for the equipment and the cost are low, so that large-scale production can be realized.
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Description

technical field

[0001] The invention relates to a lithium ion battery cathode material, in particular to a lithium iron phosphate cathode material and a preparation method thereof. Background technique

[0002] Lithium-ion batteries have been widely used in many fields since their commercial production in 1990. Olivine LiFePO 4 As a new lithium-ion battery cathode material, it has the following unique advantages compared with common transition metal oxide cathode materials: the theoretical specific capacity can reach 170mAh / g, and the actual specific capacity in industrial production can reach more than 145mAh / g; Stable discharge voltage platform; long cycle life, which can reach more than 1000 times; good high temperature performance and thermal stability; wide working temperature range (-20°C ~ 75°C); stable structure, O and P are firmly combined with strong covalent bonds, It is difficult to decompose the material by oxygen evolution, and has excellent safety performanc...

Claims

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