Process for reducing impacts on LixFeyPzO4 caused by impurity elements in ferrophosphorus

A technology of impurity elements and phosphorus elements, applied in the field of purification and low-cost development of high-performance electrode materials LixFeyPzO4, can solve the problems of not using oxygen to react raw materials, high raw material and preparation costs, complex processes, etc.

Inactive Publication Date: 2011-08-31
SICHUAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Currently commercial Li x Fe y P z o 4 A major problem that still exists in the preparation process of the method is: adopt the salt containing a kind of metal or metal simple substance to make reactant, adopt unstable ferrous salt as raw material, provide protective atmosphere with argon, nitrogen, hydrogen or C, to The limit of oxygen amount is relatively strict. Oxygen is not used as the reaction raw material. In addition, other elements are deliberately added to dope and modify to improve performance. The cost of raw materials and preparation is high, and the tap density of the material is low.
These impurity elements may affect the electrochemical performance of the material. At present, they are mostly purified by mechanical treatment, regional melting, recrystallization, etc., which need to be completed under an inert atmosphere at a higher temperature. The process is more complicated and the cost of impurity removal is higher.

Method used

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  • Process for reducing impacts on LixFeyPzO4 caused by impurity elements in ferrophosphorus
  • Process for reducing impacts on LixFeyPzO4 caused by impurity elements in ferrophosphorus
  • Process for reducing impacts on LixFeyPzO4 caused by impurity elements in ferrophosphorus

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Embodiment 1

[0034] Fe 2 Preparation of LiFePO from P and lithium carbonate 4After dissolving ferrophosphorus with aqua regia, elemental analysis is carried out. The raw material of ferrophosphorus contains 67.7% Fe, 18.9% P, 6.3% Si, 2.1% Mn, 1.3% Ti, 1.2% V, 1.2% C, the remaining insoluble impurity content is 1.3%, according to the calculation, the composition of ferrophosphorus is approximately Fe 2 P, since C is burned off during the reaction, the real impurity elements are Si, Mn, Ti, V and insoluble impurities. It is worth noting that: according to literature reports, Si, Mn, Ti and V are beneficial to improve the 4 The electrochemical performance of the positive electrode material, and the impurity elements Si, Mn, Ti and V in the actual reaction process will affect the LiFePO 4 Perform in-situ self-doping. Here, it may be assumed that Si, Mn, Ti, V and insoluble impurities are the impurity elements to be removed in ferrophosphorus. According to their physical and chemical proper...

Embodiment 2

[0051] Preparation of LiFePO from iron phosphorus FeP and lithium hydroxide as raw materials 4 , after elemental analysis, the ferrophosphorus raw material contains 54.1% Fe, 29.8% P, 7.3% Si, 2.1% Mn, 1.5% Ti, 1.5% V, 2.2% C, and the remaining insoluble impurities are 1.5%, according to the calculation, the composition of ferrophosphorus is approximately FeP, since C is burned off during the reaction process, and 0.3% of other impurities are allowed to exist in battery grade raw materials, so the real impurity elements are Si, Mn, Ti, V and insoluble impurities, it is worth noting that according to literature reports Si, Mn, Ti and V are beneficial to improve LiFePO 4 The electrochemical performance of the positive electrode material, and the impurity elements Si, Mn, Ti and V in the actual reaction process will affect the LiFePO 4 Perform in-situ self-doping. Here, it may be assumed that Si, Mn, Ti, V and insoluble impurities are the impurity elements to be removed in ferr...

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Abstract

The invention relates to a process for reducing the impacts on LixFeyPzO4 caused by impurity elements in ferrophosphorus, which belongs to the field of material chemical industry. The process comprises the following steps: firstly dissolving and filtering products of the ferrophosphorus and lithium salt under the oxidative atmosphere, then obtaining Li3PO4 filtrate and a Fe2O3 filter cake, carrying out concentration and granulation on the filtrate for obtaining high purity spherical Li3PO4, carrying out acid dissolution, filtration and reaction with phosphoric acid or phosphate on the filter cake, then controlling the temperature and the pH value for obtaining FePO4 precipitate, filtering, washing and drying for obtaining high purity FePO4, finally mixing the Li3PO4, the FePO4 and supplementary raw materials, then carrying out reaction under the non-oxidizing atmosphere for obtaining LixFeyPzO4. The method can reduce the impurity elements in the ferrophosphorus, simplify the control of oxygen content and improve the tap density of the product, and the ferrophosphorus can replace carbon.

Description

technical field [0001] The invention relates to a method for reducing the impurity elements of phosphorus and iron to Li x Fe y P z o 4 Influenced process, which can be applied to the purification of ferrophosphorus recycling process and high-performance electrode material Li x Fe y P z o 4 low-cost development. Background technique [0002] Li x Fe y P z o 4 It is a new type of green energy electrode material with great potential, mainly including LiFePO 4 , LiFe 2 / 3 PO 4 and Li 4 / 7 Fe 4 / 7 P 8 / 7 o 4 And its compound, the market space is broad. Among these electrode materials, LiFePO 4 Due to its unique structure and performance, it has attracted much attention, but the current high preparation cost hinders its large-scale application in power batteries, and people have tried various ways to reduce costs and improve performance. However, due to the bottleneck of the process route and raw materials, the commercial LiFePO on the market 4 It needs to be car...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/45H01M4/58
CPCY02E60/12Y02E60/10
Inventor 王贵欣闫康平李秀丽刘睿陈妙
Owner SICHUAN UNIV
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