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Preparation method of lithium iron phosphate precursor

A lithium iron phosphate and precursor technology is applied in the field of preparation of lithium iron phosphate precursor, which can solve the problem of low amount of LiFePO4, and achieve the effect of improving reaction effect, good commercialization prospect, good high charge-discharge performance and cycle performance.

Inactive Publication Date: 2013-04-17
TIANJIN NENGYUANGU TECH CO LTD
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Problems solved by technology

But the formation of FePO 4 A portion of the PO4 in the solution is consumed 3+ , resulting in actually obtained LiFePO 4 The amount is lower than the theoretical value (see [The Chinese Journal of Nonferrous Metals.2005,15(12):2034-2039])

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  • Preparation method of lithium iron phosphate precursor
  • Preparation method of lithium iron phosphate precursor
  • Preparation method of lithium iron phosphate precursor

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preparation example Construction

[0020] see figure 1 , which is a flowchart of a method for preparing a lithium iron phosphate precursor according to a preferred embodiment of the present invention. The present invention specifically provides a high-shear method for preparing a lithium iron phosphate precursor, comprising the following steps: weighing lithium salt, ferrous salt and phosphate in a molar ratio of 3: (0.9-1.5): 1.2 (step S1) ; Formulate the lithium salt, ferrous salt and phosphate into a standard aqueous solution of a certain concentration (step S2); weigh the carbon source according to the mass fraction of 1-50g / L (step S3), and formulate the carbon source into A standard aqueous solution of a certain concentration (step S4); using a high-shear mixer to rapidly mix the above materials continuously or dropwise (step S5).

[0021] In a preferred embodiment, the above-mentioned lithium salt is one of lithium hydroxide and lithium phosphate or a mixture of both.

[0022] In a preferred embodiment...

Embodiment approach 1

[0028] Weigh lithium salt, ferrous salt and phosphate according to molar ratio Li: Fe: P = 3: (0.98 ~ 1): 1.2. 79.238g (ie 0.294mol) of FeSO 4 ·7H 2 O was dissolved in water and diluted to 150 mL. Add 35g of glucose to the phosphoric acid solution and dilute to 100mL.

[0029] The above materials were circulated in a high shear continuous mixer to achieve uniform mixing.

[0030] Add the high-shear mixed precursor into the autoclave, and after purging the air in the autoclave with an inert gas, seal the autoclave and react at 140-350°C for 30-600 minutes.

[0031] After the above reaction is completed, quickly cool to 30°C with condensed water, take out the product, filter and wash until there is no sulfate ion; the filter cake is vacuum-dried at 80 ~ 120°C for 12 hours.

[0032] The product obtained in the previous step was calcined at 700°C for 4 hours to obtain 40g LiFePO4 / C product.

Embodiment approach 2

[0034] Weigh lithium salt, ferrous salt and phosphate according to molar ratio Li: Fe: P = 3: (0.98 ~ 1): 1.2. 79.238g (ie 0.294mol) of FeSO 4 ·7H 2 O was dissolved in water and diluted to 150 mL. Add 35g of glucose to the phosphoric acid solution and dilute to 100mL.

[0035] Add the above materials dropwise to a high shear batch mixer and mix rapidly.

[0036] Add the high-shear mixed precursor into the autoclave, and after purging the air in the autoclave with an inert gas, seal the autoclave and react at 140-350°C for 30-600 minutes.

[0037] After the above reaction is completed, quickly cool to 30°C with condensed water, take out the product, filter and wash until there is no sulfate ion; the filter cake is vacuum-dried at 80 ~ 120°C for 12 hours.

[0038] The product obtained in the previous step was calcined at 700°C for 4 hours to obtain 40g LiFePO 4 / C product.

[0039] see Figure 2 to Figure 4 , figure 2 LiFePO which is a preferred embodiment of the presen...

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Abstract

The invention provides a preparation method of a lithium iron phosphate precursor. The preparation method of the lithium iron phosphate precursor comprises the following steps of: weighing lithium salt, ferrous salt and phosphate in a mol ratio of 3: (0.9-1.5): 1.2; preparing the lithium salt, the ferrous salt and the phosphate into a standard aqueous solution at a certain concentration; weighing a carbon source according to a mass fraction of 1-50 g / L; preparing the carbon source into a standard aqueous solution at a certain concentration; and quickly mixing the materials continuously or dropwise by using a high-shear mixer. By a high-shear mixing technology, precursor particles are mixed uniformly by an impinging stream, the particle size and the particle size distribution of the precursor particles are reduced, the electrochemical performance of a LiFePO4 / C material is improved as well as the reaction time is shortened; and the preparation method is small in equipment investment and simple in process operation, can achieve both intermittent operation and large-scale continuous production and has a relatively good commercial prospect.

Description

technical field [0001] The invention relates to a lithium battery technology, in particular to a preparation method of a lithium iron phosphate precursor. Background technique [0002] The positive electrode material is the core of lithium-ion batteries. At this stage, lithium cobalt oxide (LiCoO 2 ), lithium manganate (LiMn 2 o 4 ) and lithium iron phosphate (LiFePO 4 ) dominated, in which LiFePO with olivine structure 4 , as one of the most promising cathode materials is receiving more and more attention, however, currently LiFePO 4 The synthesis method is relatively simple, such as LiFePO 4 The main manufacturers of battery cathode materials, Valence, A123 and Tianjin Strand in the United States, all use the traditional solid-phase method or the improved solid-phase method. The product cost of this method is relatively high, and the product batches are unstable. [0003] As a low-temperature and economical method for synthesizing nanomaterials, hydrothermal synthesi...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58B01F3/08
CPCY02E60/10
Inventor 张金利刘媛媛杨赛谷俊杰
Owner TIANJIN NENGYUANGU TECH CO LTD
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