Anode material lanthanum or Ac adulterated LiFePO4 of lithium ion secondary battery and its making method

A secondary battery and positive electrode material technology, applied in battery electrodes, chemical instruments and methods, circuits, etc., can solve the problems of poor high-current discharge performance, difficult control and operation, and obstacles to practical applications, etc., and achieve high tap density , good crystallization, and good high-current discharge performance

Inactive Publication Date: 2008-03-26
TIANJIN B&M SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But the following shortcomings hinder its practical application: (1) Fe in the synthesis 2+ easily oxidized to Fe 3+ , it is not easy to obtain single-phase LiFePO 4
(2) LiFePO 4 Its own conductivity is very low, resulting in poor high-current discharge performance
(3) The tap density is low
[0004] Existing research to improve LiFePO through the following aspects 4 Performance: (1) Use inert gas to protect Fe 2+ ; but fully protected by inert gas, it is not easy to control and operate, and it is easy to cause Fe 2+ is oxidized to Fe 3+
(2) The surface is mixed or coated with conductive carbon materials to increase the electronic conductivity between the matrix particles, but the tap density of the obtained product is low

Method used

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  • Anode material lanthanum or Ac adulterated LiFePO4 of lithium ion secondary battery and its making method
  • Anode material lanthanum or Ac adulterated LiFePO4 of lithium ion secondary battery and its making method

Examples

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Embodiment 1

[0029] A lithium ion secondary battery cathode material lanthanum-doped lithium iron phosphate, characterized in that the molecular formula is LiLa x Fe 1-x PO 4 , where x=0.01, has an olivine structure.

[0030] A kind of preparation method of above-mentioned lithium ion secondary battery cathode material lanthanum-doped lithium iron phosphate, it is characterized in that comprising the following steps:

[0031] (1). Using lithium carbonate Li 2 CO 3 , ferrous oxalate FeC 2 o 4 .2H 2 O, ammonium dihydrogen phosphate NH 4 h 2 PO 4 , lanthanum carbonate La 2 (CO 3 ) 3 As a raw material, by atomic ratio Li:Fe:P:La=1:(1-x):1:x, 0.5mol lithium carbonate Li 2 CO 3 , 0.99mol ferrous oxalate FeC 2 o 4 .2H 2 O, 1mol ammonium dihydrogen phosphate NH 4 h 2 PO 4 and 0.005mol lanthanum carbonate La 2 (CO 3 ) 3 Add it to the ball mill tank of the planetary four-head fast ball mill, and add 1000g of zirconia grinding balls, then add 150ml of acetone, and wet mill in t...

Embodiment 2

[0040] A lithium ion secondary battery cathode material lanthanum-doped lithium iron phosphate, characterized in that the molecular formula is LiLa x Fe 1-x PO 4 , where x=0.02, has an olivine structure. Its preparation step just changes ferrous oxalate FeC in embodiment 1 step (1). 2 o 4 .2H 2 The amount of O added is 0.98mol, lanthanum carbonate La 2 (CO 3 ) 3 The addition amount of the mixture is 0.01mol, and the wet grinding time is 7h; the mixed material dried in step (3) is heated up to 480°C, and kept for 4h; other is the same as in Example 1. The molecular formula is obtained as LiLa 0.02 Fe 0.98 PO 4 , a cathode material with an olivine structure.

Embodiment 3

[0042] A lithium-ion secondary battery cathode material lanthanum-doped lithium iron phosphate, characterized in that the molecular formula is: LiLa x Fe 1-x PO 4 , where x=0.03, has an olivine structure. Its preparation step just changes ferrous oxalate FeC in embodiment 1 step (1). 2 o 4.2 h 2 The amount of O added is 0.97mol, lanthanum carbonate La 2 (CO 3 ) 3 The addition amount of is 0.015mol; In the step (6), the dry ball milling time is changed into 6h; In the step (7), N 2 、H 2 Mixed gas (by volume, H 2 Accounting for about 5%), the reaction temperature of the dried calcined material is 500° C., and it is kept for 16 hours for secondary calcination; the others are the same as in Example 1. The molecular formula is obtained as LiLa 0.03 Fe 0.97 PO 4 , a cathode material with an olivine structure.

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Abstract

This invention relates to FeLiPO4 doped with La or Ac, positive material of Li ionic secondary cells and its preparation method characterizing that the formula is: LiMxFe1-xPO4 (M is La or Ac, 0.01<-x<-0.05) in the structure of olivine, the preparation includes the following steps: taking Li compound, Fe, phosphate, La or Ac as the raw materials to add them into a ball mill for wet mill then putting them into N2 and H2 mixed atmosphere for pre-calcining, then wet-grinding them and drying them and then ball-milling them, then putting them into N2 and H2 mixed atmosphere for secondary calcining to get the invented positive material. Advantages: fine crystalizatin, conduction performance of ions is good and discharge performance of heavy current is good, tap density is great and the problem of easy oxidation of Fe2+ is solved.

Description

technical field [0001] The invention relates to the field of lithium ion secondary battery positive electrode materials, in particular to a lithium ion secondary battery positive electrode material doped with lanthanum or actinium lithium iron phosphate and a preparation method thereof. technical background [0002] Lithium-ion secondary battery is a new type of green high-energy rechargeable battery that appeared in the 1990s. It has many advantages such as high voltage, high energy density, good cycle performance, small self-discharge, no memory effect, and wide operating 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 important part of the lithium-ion battery. During the charging and discharging p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/48C01B25/45
CPCY02E60/12Y02E60/10
Inventor 周大桥吴孟涛宋英杰伏萍萍陈菁菁
Owner TIANJIN B&M SCI & TECH
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