Method for preparing lithium enriched lithium ion phosphate powder

A technology of lithium iron phosphate and powder, which is applied in the field of preparation of electrochemical power source materials, achieves obvious effects and advantages, wide application prospects, and the effect of improving the matrix basic capacity and cycle electrical performance

Inactive Publication Date: 2006-07-19
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This design approach works well in Lithium Iron Phosphate (LiFePO 4 ) has not been applied and reported in the material

Method used

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  • Method for preparing lithium enriched lithium ion phosphate powder

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preparation example Construction

[0019] The specific method of the preparation method of the lithium-rich type lithium iron phosphate powder is as follows:

[0020] Lithium salt, ferrous salt, phosphate and substitutes are fed at one time according to the molar ratio of element Li:Fe:P:B=(1+2x):1:(1-x):x, and then deionized water, At least one of industrial alcohol and absolute ethanol is used as the mixing medium, and the mixing and ball milling time is 6-12 hours, dried at 40-70°C, heated at 400-550°C under an inert atmosphere or a reducing atmosphere, and kept for 5-10 hours. Carry out pre-calcination within 1 hour; ball mill the pre-calcined material for 6-12 hours for the second time, dry it at 40-70°C, and then heat it at 550-850°C for the second calcination under an inert or reducing atmosphere to obtain lithium-rich lithium iron phosphate Li 1+2x Fe(P 1-x B x )O 4 Powder.

[0021] The boron substitution source is at least one of boric acid, trimethyl borate and boron oxide.

[0022] The lithium ...

Embodiment 1

[0029] 0.05025 moles of lithium carbonate Li 2 CO 3 , 0.1 mole ferrous oxalate Fe(C 2 o 4 )·2H 2 O and 0.09975 moles of ammonium dihydrogen phosphate NH 4 h 2 PO 4 and 0.00025 moles of boric acid H 3 BO 4 Mix, add to a polyester tank, add 55ml of absolute alcohol, seal and mix on a planetary ball mill for 10 hours, discharge and dry under a nitrogen atmosphere of 0.3 liters / minute, and raise the temperature to 400°C, keep it at this temperature for 8 hours, cool down to room temperature with the furnace, and get the pre-fired material, then use industrial alcohol as the medium for ball milling for 6 hours, and dry the material under 0.3 liters / min of nitrogen atmosphere at 4°C / min. The heating rate of 1 minute is raised to 700 ° C, and the temperature is kept at this temperature for 8 hours, and then the temperature is lowered to room temperature with the furnace, and the positive electrode material Li 1.005 Fe(P 0.9975 B 0.0025 )O 4 , recorded as B1.

[0030] The...

Embodiment 2

[0032] 0.1015 mol lithium hydroxide LiOH·H 2 O, 0.1 mole of ferrous acetate Fe(CH 3 COO) 2 2H 2 O and 0.09925 moles of diammonium hydrogen phosphate (NH 4 ) 2 HPO 4 and 0.00075 moles of trimethyl borate (CH 3 O) 3 B is mixed, put into the polyester tank, add 80ml of industrial alcohol, seal and mix on the planetary ball mill for 6 hours. 430°C, keep warm at this temperature for 7.5 hours, cool down to room temperature with the furnace, take out the pre-fired material and add it to the polyester tank, add an appropriate amount of deionized water, seal it and ball mill it for 10 hours, and dry it at 0.3 liters / minute Under a nitrogen-hydrogen mixed atmosphere (nitrogen:hydrogen = 9:1, volume ratio), the temperature was raised to 720°C at a rate of 4°C / min, kept at this temperature for 7 hours, and cooled to room temperature with the furnace to obtain the positive electrode material Li 1.015 Fe(P 0.9925 B 0.0075 )O 4 , recorded as B2.

[0033] Weigh 1.125gLi 1.015 Fe...

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Abstract

The invention discloses a preparation method for lithium-rich ferrous lithium phosphate powder with molecular formula as Li(1+2x)Fe(P1-xBx)O4 in electrochemical power source material. Wherein, mixing the lithium salt, ferrous iron salt, phosphorus salt and substitude of borone-containing compound as given mole ratio; baking, pre-calcining, and hihg-temperature secondary calcining to obtain the product. This invention is convenient to realize part substitude and lithium enrichment on parent body with solid phase method to improve cell capacity and cycle performance, and has wide application future.

Description

technical field [0001] The invention belongs to the technical field of preparation of electrochemical power source materials. In particular, it relates to a preparation method of a lithium-rich lithium iron phosphate powder used as a common secondary lithium ion battery or a modified lithium ion battery positive electrode material for power energy. technical background [0002] Lithium-ion battery is a new type of green high-energy rechargeable battery that appeared in the early 1990s. It has many advantages such as high voltage, high energy density, good cycle performance, small self-discharge, no memory effect, and wide operating temperature range. It is widely used in mobile Telephones, notebook computers, portable electric tools, electronic instruments, weapons and equipment, etc. also have good application prospects in electric vehicles, and have become the focus of research and development by countries all over the world. The positive electrode material is an importan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45C01B25/26H01M4/58H01M4/36
CPCY02E60/10
Inventor 唐子龙罗绍华张中太卢俊彪闫俊萍
Owner TSINGHUA UNIV
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