A kind of hydrothermal method prepares the method for lithium iron phosphate equimolar

Abstract

The present invention discloses a method of preparing iron phosphate such as water and heat method. The steps include (1) the iron phosphate stabilizer dissolved in oxygen distilled water, stir and add the sub -railway source to form a mixture A;2) According to Fe2+: li+= 1: 1, weigh LiH2PO4 dissolved to form solution B; (3) mix mixture A with solution B, add a high -pressure reactor, adjust pH = 6 ~ 8;The wave -type heating reactor to 160 ~ 200 ° C for 4 ~ 6h, naturally cool to room temperature, filter, washing, and vacuum drying.The Lifepo4 positive material made by this method is excellent, and the 0.2C discharge ratio has a capacity of 152mAh / g.

Description

technical field [0001] The invention relates to the field of positive electrode materials for lithium ion batteries, in particular to a method for preparing lithium iron phosphate in equimolar quantities by a hydrothermal method. Background technique [0002] In recent years, the application of lithium-ion batteries in the field of new energy has attracted more and more attention. Subsequently, as one of the core parts of lithium-ion batteries, cathode materials have become a research hotspot. The lithium iron phosphate material has the advantages of wide sources, low cost, low toxicity, easy recycling, good safety performance, long service life and high specific capacity, and is currently one of the most popular and reliable candidate cathode materials. [0003] At present, in many preparation methods and electrochemical performance improvement of lithium iron phosphate, solid-phase method, sol-gel method, hydrothermal method, carbon coating, metal ion doping, etc. occupy a...

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Problems solved by technology

For example: Wang et al. (Electrochem Acta, 2005, 50, 14) used a solid-state reaction method to prepare Fe-site-doped cathode material LiFe 0.9 Mg 0.1 PO 4 ; Jin et al. (J PowerSources, 2008, 178) synthesized LiFePO by hydrothermal method 4 , with LiOH, FeSO 4 , H 3 PO 4 As raw material, the molar ratio is 3:1:1, first mix phosphoric acid and ferrous sulfate, add a small amount of distilled water to stir, then add lithium hydroxide solution to the mixed solution, stir and then transfer to the reaction kettle, in the dry box at 180 Heating at ℃ for 5 hours; in this method, lithium source: iron source: phosphorus source is 3:1:1, a large amount of lithium source in the solution neutralizes redundant anions, resulting in waste of raw material costs, and metal iron ions are easy to react with phosphate Agglomeration occurs and precipitates at the bottom of the autoclave, and insufficient contact with lithium ions leads to high content of reaction impurities, high cost and complicated operation

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