A kind of cathode material lithium ferrous phosphate for lithium ion battery and preparation method thereof

Abstract

The invention discloses a method for preparing positive pole material LiFePO4 for a lithium ion battery, which uses ferrous oxalate as a ferrous resource, and adopts a nano ceramic grinding and dispersion machine. The method comprises the steps as follows: preparing raw materials including the ferrous oxalate, a lithium resource, a phosphor source and a metal element doped compound; mixing, pulping and drying the raw materials, and obtaining a powdery precursor; pre-burning the powdery precursor; performing secondary material proportioning of products obtained via pre-burning, grinding the mixture to be nano-grade by adopting the nano ceramic grinding and dispersion machine, sintering the mixture after drying, and obtaining the positive pole material LiFePO4 of the lithium ion battery. The prepared LiFePO4 is 0.5-6 micrometres in particle size D50, 15-25 m<2> / g in specific area and not less than 1.5 g / cm<3> in tap density. According to the invention, the technique is simple and easy to control, the production cost is low, components of the product are uniform, and both the physical and chemical properties and the electrical performance are favorable.

Description

technical field [0001] The invention relates to a lithium ion battery cathode material and its preparation, in particular to a lithium iron phosphate prepared by using a nano ceramic grinding and dispersing machine with ferrous oxalate as an iron source and a preparation method thereof. Background technique [0002] Since the successful development of lithium-ion batteries in the 1990s, they have been widely used in portable devices due to their advantages such as high energy density, good cycle performance and low self-discharge, and are considered ideal for aerospace, electric vehicles and hybrid vehicles. 电源(参见XuB,QianD,WangZY,MengYS.Recentprogressincathodematerialsresearchforadvancedlithiumionbatteries[J].MaterialsScienceandEngineeringR,2012,73:51-65;ZhangSS,ReadJA.Anewdirectionfortheperformanceimprovementofrechargeablelithium / sulfurbatteries[J].JournalofPowerSources,2012,200:77-82.)。 [0003] Cathode materials, as an important part of lithium-ion batteries, have always b...

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Problems solved by technology

Nano-lithium iron phosphate is an important way to improve the diffusion rate of lithium ions, but there are still many problems to be studied in the preparation method of nano-lithium iron phosphate electrode materials mentioned above: (1) How to improve the lithium iron phosphate battery Tap density; (2) How to choose a suitable preparation method to improve the crystallization degree of the electrode under the premise of ensuring the nanometer particle size of the lithium iron phosphate material, so as to obtain a stable working voltage of the battery; (3) Lithium iron phosphate nanomaterials in The problem of irreversible capacity loss caused by severe agglomeration during charging and discharging; (4) How to ensure the quality stability of different production batches

In addition, the above-mentioned preparation method of nano-lithium ferrous phosphate is difficult to industrialize, the process operation steps are complicated, and the cost is high. The chemical raw materials such as organic solvents used in the process are likely to pollute the environment, and the environmental protection of the process needs to be further improved. improve

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