Method for liquid-phase synthesis of nano spherical lithium battery anode material lithium iron phosphate

A positive electrode material, lithium iron phosphate technology, applied in the direction of phosphorus compounds, chemical instruments and methods, inorganic chemistry, etc., can solve the problems of high requirements for synthesis equipment, unfavorable industrial production, large particle size of products, etc. Conditions and experimental equipment requirements are low, the effect of uniform particle size distribution

Active Publication Date: 2015-09-02
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Currently, LiFePO 4 There are many preparation methods, among which the high-temperature solid-phase method is the most commonly used, which has been widely used in industrial mass production, but the product obtained by calcining for more than ten hours has a large and uneven particle size, and the product variation between production batches poor consistency, resulting in LiFePO 4 The specific capacity is seriously attenuated, which reduces the cycle life
Similarly, other methods such as hydrothermal synthesis, sol-gel method, co-precipitation method, microwave sintering method, carbothermal reduction method, etc. not only require high synthesis equipment and complicated operation technology, but also have low final yield of products, which are only suitable for experiments. Small batch research in the laboratory is not conducive to industrial production

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  • Method for liquid-phase synthesis of nano spherical lithium battery anode material lithium iron phosphate
  • Method for liquid-phase synthesis of nano spherical lithium battery anode material lithium iron phosphate
  • Method for liquid-phase synthesis of nano spherical lithium battery anode material lithium iron phosphate

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Embodiment 1

[0038] A nano-spherical lithium battery cathode material LiFePO 4 The method for liquid-phase method synthesis, comprises the steps:

[0039] (1) FePO 4 2H 2 Preparation of O: Weigh 27.4g FeSO 4 ·7H 2 O and 11.5gNH 4 h 2 PO 4 (Fe / P molar ratio is 1:1) respectively dissolved in distilled water to make 1mol L -1 solution, mix the two solutions evenly under stirring, add 20mg polyvinyl alcohol, drop 7.34g H 2 o 2 Aqueous solution (mass concentration is 30%, Fe / H 2 o 2 The molar ratio is 1:0.6), with NH 3 ·H 2 O adjusts the pH to 2, particles are generated, and filtered to obtain filtrate 1 and particle 1, and particle 1 is washed with distilled water until it is washed with Ba(OH) 2 Solution detects no SO in the washed filtrate4 2- , dried at 80°C to obtain FePO 4 2H 2 0; 20mg polyvinyl alcohol can make the particles generated in the reaction solution uniformly dispersed and uniform in appearance;

[0040] (2) LiFePO 4 Preparation: Weigh 3.78g FePO 4 2H 2 O an...

Embodiment 2

[0050] A nano-spherical lithium battery cathode material LiFePO 4 The method for liquid-phase method synthesis, comprises the steps:

[0051] (1) FePO 4 2H 2 Preparation of O:

[0052] Adopt the filtrate 1 that embodiment 1 step (1) obtains to replace the dissolved FeSO in embodiment 1 step (1) 4 and NH 4 h 2 PO 4 The amount of distilled water used is not enough to make up with distilled water, and others obtain FePO with embodiment 1 step (1). 4 2H 2 O, called step (1) cycle 1 time, denoted as #A, similarly, recycle 2, 3, 4, 5 times of filtrate 1 to prepare FePO 4 2H 2 O, recorded as #B, #C, #D, #E in turn.

[0053] (2) with embodiment 1 step (2);

[0054] (3) Characterization of the product: see the discharge curve of the product Figure 6 .

Embodiment 3

[0056] A nano-spherical lithium battery cathode material LiFePO 4 The method for liquid-phase method synthesis, comprises the steps:

[0057] (1) FePO 4 2H 2 The preparation of O: with embodiment 1 step (1);

[0058] (2) Use the filtrate 2 obtained in Example 1 step (2) to replace the ethanol in Example 1 step (2) as a solvent, the amount is not enough to make up with absolute ethanol, and the others are the same as Example 1 step (2) to obtain LiFePO 4 , which is called step (2) cycle 1 time, denoted as #1, similarly, the filtrate 2 is recycled twice to obtain LiFePO 4 , denoted as #2.

[0059] (3) Characterization of the product: see the discharge curve of the product Figure 7 .

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Abstract

The invention discloses a method for liquid-phase synthesis of nano spherical lithium battery anode material lithium iron phosphate. The method comprises the following steps: respectively dissolving ferrite and a phosphate compound with distilled water, mixing, adding an assistant, dropping an H2O2 water solution, adjusting the pH, generating particles, and filtering to obtain filtrate 1 and particles 1; washing the particles 1, and drying to obtain FePO4.2H2O; adding the FePO4.2H2O and a lithium compound to a solvent, stirring evenly, adding a reducing agent, reacting, standing and filtering to obtain filtrate 2 and particles 2; and washing the particles 2 with ethanol, drying, and burning in an argon atmosphere to obtain LiFePO4. According to the method, the raw material source is wide; and vitamin C and dextrose monohydrate are adopted by the reducing agent, so that the cost is low; the reduction effect is good; the requirements on reaction conditions and experiment equipment are relatively low; the energy consumption is low; a waste liquid can be recycled, so that the problem of environmental pollution is avoided; zero emission is realized; and the prepared nano spherical particle is uniform in morphology and uniform in particle size distribution.

Description

technical field [0001] The invention relates to a nano-spherical LiFePO 4 Preparation method of lithium battery cathode material. Background technique [0002] Since 1997, Padhi et al. proposed LiFePO as the cathode material for lithium-ion batteries. 4 Since, LiFePO with olivine structure 4 As a cathode material for lithium-ion power batteries, it has become one of the current research hotspots due to its advantages such as low cost, non-toxicity, abundant raw material sources, and good high-temperature electrochemical performance. Compared with the traditional secondary power cathode material LiCoO 2 , LiNiO 2 , LiMn 2 o 2 Compared with lithium battery cathode material LiFePO 4 It has relatively high specific capacity (170mAh / g), stable working voltage (3.5V) and long cycle life, and it has abundant raw materials, low price, good thermal and chemical stability, and is environmentally friendly. P and O are firmly combined with extremely strong covalent bonds, making...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45
Inventor 王兴尧祖雪敏马君君
Owner TIANJIN UNIV
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