Preparation of Fe5(PO4)4(OH)3 and application thereof

A reaction kettle and post-reaction technology, which is applied in the field of electrochemistry, can solve problems such as difficult deintercalation, inconspicuous effect, and low capacity, and achieve the effects of reduced preparation cost, outstanding high temperature stability, and short synthesis cycle

Inactive Publication Date: 2008-10-01
BEIJING UNIV OF TECH
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, researchers mainly improve the electronic conductivity and ion diffusion rate of the material by coating the surface conductive substance or doping the bulk phase with high-valent metal ions, but the effect is not obvious.
In 2007, Ellis et al reported the solid solution material Na 2 FePO 4 F and its solid solution discharge curve, trying to change the defects of the crystal material itself through the form of solid solution, the results show that Na 2 FePO 4 The solid solution discharge of F material may fundamentally overcome the defects of the crystal material itself, and improve the conductivity and ion diffusion rate. However, Na + Li + The radius is large, it is not easy to complete the de-embedding, resulting in extremely low capacity

Method used

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  • Preparation of Fe5(PO4)4(OH)3 and application thereof
  • Preparation of Fe5(PO4)4(OH)3 and application thereof
  • Preparation of Fe5(PO4)4(OH)3 and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] 1) Weigh 0.399g Fe 2 (SO 4 ) 3 , 0.098g H 3 PO 4 and 0.042g LiOH·H 2 O (molar ratio Li:Fe:PO 4 3+ =1:2:1), the H 3 PO 4 Add in 200ml steel reactor, and add 50ml distilled water, then Fe 2 (SO 4 ) 3 Add to the reaction kettle, and keep stirring, then add LiOH·H 2 0, the pH of the solution was recorded to be about 2 at this time, and the color of the solution was white and yellowish, and the reaction kettle was sealed;

[0022] 2) Control the heating rate to about 10°C / min, raise the temperature of the reactor to 220°C, and keep it warm for 2 hours;

[0023] 3) The resulting product solution was washed and clarified with distilled water, and placed in a vacuum oven at 80° C. for 2 hours after suction filtration to obtain the dark green product Fe 5 (PO 4 ) 4 (OH) 3 2H 2 O;

[0024] 4) Fe 5 (PO 4 ) 4 (OH) 3 2H 2 O to N 2 Under protective conditions, heat preservation at 400°C for 5 hours to prepare the lithium ion battery cathode material Fe 5 (PO ...

Embodiment 2

[0027] 1) Weigh 1.9994g Fe 2 (SO 4 ) 3 , 0.49g H 3 PO 4 and 0.2098g LiOH·H 2 O (molar ratio Li:Fe:PO 4 3+ =1:2:1), the Fe 2 (SO 4 ) 3 Add 200ml steel reaction kettle, and add 80ml distilled water, then add H 3 PO 4 Add to the reaction kettle, keep stirring, then add LiOH·H 2 0, the pH of the solution was recorded to be about 1.9 at this time, and the color of the solution was white and yellowish, and the reaction kettle was sealed;

[0028] 2) Control the heating rate to about 8°C / min, raise the temperature of the reactor to 200°C, and keep it warm for 1.5 hours;

[0029] 3) The resulting product solution was washed and clarified with distilled water, and placed in a vacuum oven at 120° C. for 1 hour after suction filtration to obtain the dark green product Fe 5 (PO 4 ) 4 (OH) 32H 2 O;

[0030] 4) Fe 5 (PO 4 ) 4 (OH) 3 2H 2 O to N 2 Under protective conditions, after holding at 450°C for 3 hours, the lithium-ion battery cathode material Fe 5 (PO 4 ) ...

Embodiment 3

[0033] 1) Weigh the reactant 0.399g Fe 2 (SO 4 ) 3 , 0.098g H 3 PO 4 and 0.042g LiOH·H 2 O (molar ratio Li:Fe:PO 4 3+ =1:2:1), the H 3 PO 4 Add in 200ml steel reaction kettle, and add 60ml distilled water, then Fe 2 (SO 4 ) 3 Add to the reaction kettle, keep stirring, then add LiOH·H 2 0, the pH of the solution measured at this moment was about 2.0, and the color of the solution was white and yellowish, and the reaction kettle was sealed;

[0034] 2) Control the heating rate to about 12°C / min, raise the temperature of the reactor to 210°C, and keep it warm for 2.5 hours;

[0035] 3) The resulting product solution was washed and clarified with distilled water several times, and then placed in a vacuum oven at 100°C for 2 hours after suction filtration to obtain the dark green product Fe 5 (PO 4 ) 4 (OH) 3 2H 2 O;

[0036] 4) Fe 5 (PO 4 ) 4 (OH) 3 2H 2 O to N 2 Under protective conditions, after holding at 350°C for 4 hours, the lithium-ion battery cathod...

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Abstract

The invention relates to the preparation of a Fe5(PO4)4(OH)3 and the application belonging to the electrochemistry field. The positive electrode material of the existing lithium ion battery has the problems of low conductivity, ion diffusion rate and capacity, and so on. Through the invention, a lithium salt, an iron salt and a phosphate are added into a reactor according to a mole of ratio Li<+>:Fe<3+>:PO4<3+>=1:2:1 and kept in the reactor at the temperature of 200-250 DEG C for 1.5-2.5 h; then the reaction solution is washed to be transparent by the distilled water, filtered, and dried at the temperature of 80-120 DEG C; at last, the dried product is kept at the temperature of 350-450 DEG for 3-5 h so as to get the Fe5(PO4)4(OH)3. The Fe5(PO4)4(OH)3 provided by the invention can be used as the positive electrode material of the lithium ion battery. The invention has the advantages of having simple craft, low energy consumption and low cost, being safe, and having good electrochemical properties, thermal stability and industrialization prospect.

Description

technical field [0001] The invention belongs to the field of electrochemistry, in particular to Fe 5 (PO 4 ) 4 (OH) 3 preparation and its application. Background technique [0002] With its excellent comprehensive performance, lithium-ion batteries have shown broad development space in the two major markets of portable storage batteries and environmentally friendly electric vehicle batteries. Lithium iron phosphate (LiFePO 4 ) has attracted great attention since it was proposed and synthesized by the Goodenough research group in the late 1990s, and is considered to be one of the most promising battery materials. The theoretical specific capacity of lithium iron phosphate can reach 170mAhg -1 , the discharge platform is 3.4V, which has the advantages of cheap price, environmental friendliness, stable cycle performance, high specific energy, and good thermal stability. It has broad market application prospects in electric bicycles, hybrid electric vehicles, and vehicle b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/58H01M4/48C01G49/00B01J8/00
CPCY02E60/10
Inventor 夏定国陈宇王振尧杨涛王忠丽
Owner BEIJING UNIV OF TECH
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