Method for preparing lithium cobaltate composite electrode material coated by iron phosphate

A technology of iron phosphate coating lithium cobalt oxide and composite electrodes, which is applied in electrode manufacturing, battery electrodes, chemical instruments and methods, etc., can solve the problems of loss of electrode material mass specific capacity, crystal structure damage, high price, etc., and achieve good results. Electrochemical cycle performance, improved cycle performance, and low-cost effects

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

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Problems solved by technology

However, due to the N 2 Atmosphere Fe 2+ will not be oxidized to Fe 3+ , so in fact the cladding material should be mainly Fe 3 (PO 4 ) 2 ; LiCoO 2 High-temperature calcination treatment under anoxic conditions will make LiCoO 2 The crystal structure of the electrode material is destroyed to a certain extent, and the mass specific capacity of the electrode material is lost; in addition, the expensive Fe(CH 3 CO 2 ) 2 4H 2 O is raw material and in N 2 Synthesis under harsh conditions of protection, the cost is higher

Method used

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  • Method for preparing lithium cobaltate composite electrode material coated by iron phosphate
  • Method for preparing lithium cobaltate composite electrode material coated by iron phosphate
  • Method for preparing lithium cobaltate composite electrode material coated by iron phosphate

Examples

Experimental program
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Effect test

Embodiment 1

[0032] Weigh 48.5g of LiCoO 2 material and 4.05g of Fe(NO 3 ) 3 9H 2 O, add 100mL deionized water to prepare Fe 3+ The suspension with a concentration of 0.1mol / L was ultrasonically treated for 30 minutes at a temperature of 25°C and a power of 2000W / L. Add dropwise 0.1mol / L of (NH 4 ) 2 HPO 4 Solution 120mL, where n(PO 4 3- ) / n(Fe 3+ )=1.2 / 1 (molar ratio), continue stirring for 1 hour after the dropwise addition is completed. After the reaction is completed, filter and wash with deionized water until the pH value of the filtrate is 7. The filter cake was dried in an oven at 130° C. for 6 hours, and ground for later use.

[0033] The powder material obtained by grinding is heated up to 550°C at a rate of 5°C / min, kept at a constant temperature for 10 hours, and then naturally cooled to room temperature to obtain the product of the present invention.

[0034] Using the Japan Shimadzu ICPS-7500 inductively coupled plasma emission spectrometer to measure the content o...

Embodiment 2

[0036] Weigh 74.5g of LiCoO 2 material and 2.02g of Fe(NO 3 ) 3 9H 2 O, add 100mL deionized water to prepare Fe 3+ The suspension with a concentration of 0.05mol / L was subjected to ultrasonic treatment for 60 minutes at a temperature of 20°C and a power of 800W / L. Add dropwise 0.05mol / L of (NH 4 ) 2 HPO 4 Solution 150mL, where n(PO 4 3- ) / n(Fe 3+ )=1.5 / 1 (molar ratio), continue stirring for 0.5 hour after the dropwise addition is completed. After the reaction is completed, filter and wash with deionized water until the pH value of the filtrate is 7. The filter cake was dried in an oven at 50° C. for 12 hours, and ground for later use.

[0037] The powder material obtained by grinding is heated up to 350°C at a rate of 2°C / min, kept at a constant temperature for 15 hours, and then naturally cooled to room temperature to obtain the product of the present invention. ICP and XRD tests show that the product composition is 5wt.% FePO 4 Coated LiCoO 2 The composite mate...

Embodiment 3

[0039] Weigh 84.8g of LiCoO 2 material and 12.12g of Fe(NO 3 ) 3 9H 2 O, add 100mL deionized water to prepare Fe 3+ Suspension with a concentration of 0.3mol / L is ultrasonically treated for 45 minutes at a temperature of 40°C and a power of 1000W / L. Add dropwise 0.3mol / L of (NH 4 ) 2 HPO 4 Solution 100mL, where n(PO 4 3- ) / n(Fe 3+ )=1 / 1 (molar ratio), continue stirring for 1 hour after the dropwise addition is completed. After the reaction is completed, filter and wash with deionized water until the pH value of the filtrate is 7. The filter cake was dried in an oven at 120° C. for 12 hours, and ground for later use.

[0040] The powder material obtained by grinding is heated up to 450°C at a rate of 10°C / min, kept at a constant temperature for 10 hours, and then naturally cooled to room temperature to obtain the product of the present invention. ICP and XRD tests show that the product composition is 1wt.% FePO 4 Coated LiCoO 2 The composite material belongs to th...

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Abstract

The invention relates to the preparation method of an iron phosphate coating lithium cobalt oxide composite electrode material, which belongs to the lithium ion battery electrode material and the preparation technology field. The preparation technology of the invention is that: a LiCoO2 is added into a Fe(NO3)3 solution, then an ultrasound dispersive treatment is carried out for the solution, under a mechanical agitation, a (NH4)2HPO4 solution is slowly dropped into the solution, after filtration, wash and heat treatment, the iron phosphate coating lithium cobalt composite electrode material is obtained. The invention has the advantages of having simple preparation process, good coating effect, and having good electrochemistry circulation stability and charge-off-resistant properties under the condition that the composite electrode material obtained does not reduce the specific discharge capacity of the lithium cobalt oxide.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery electrode materials and their preparation, and in particular provides an iron phosphate FePO 4 Coated Lithium Cobalt Oxide LiCoO 2 Preparation method of composite electrode material. Background technique [0002] With α-NaFeO 2 type layered LiCoO 2 It is currently the only positive electrode material that has been industrialized on a large scale and widely used in commercial lithium-ion batteries, and will dominate for a long time. But LiCoO 2 The price is expensive, and the actual specific capacity is 120-140mAh / g, which is only about 50% of its theoretical specific capacity of 274mAh / g. When the charging cut-off voltage of Li-ion battery is higher than 4.2V, LiCoO 2 A large amount of Co in the structure 3+ will become Co. 4+ ,Co 4+ The formation of will lead to the formation of oxygen vacancies, which will weaken the binding force between transition metal cobalt and oxygen, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/04B01J8/00B01J19/00
CPCY02E60/10
Inventor 杨文胜李刚杨占旭
Owner BEIJING UNIV OF CHEM TECH
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