A kind of lithium iron phosphate/lithium vanadium fluorophosphate/carbon composite cathode material and preparation method thereof

A composite positive electrode material, lithium vanadium phosphate technology, applied in the direction of battery electrodes, structural parts, electrical components, etc., can solve the problems of low discharge specific capacity and specific energy, and achieve improved discharge specific capacity, good high rate performance, multiple The effect of the migration channel

Active Publication Date: 2021-07-16
宜宾天原锂电新材有限公司
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Problems solved by technology

[0003] In order to solve the problem of low discharge specific capacity and specific energy under high-rate conditions of lithium iron phosphate in the prior art, the purpose of the present invention is to provide a lithium iron phosphate / lithium fluorovanadium phosphate / carbon composite positive electrode material without sacrificing energy Density while improving its rate performance and cycle performance

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  • A kind of lithium iron phosphate/lithium vanadium fluorophosphate/carbon composite cathode material and preparation method thereof
  • A kind of lithium iron phosphate/lithium vanadium fluorophosphate/carbon composite cathode material and preparation method thereof
  • A kind of lithium iron phosphate/lithium vanadium fluorophosphate/carbon composite cathode material and preparation method thereof

Examples

Experimental program
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Embodiment 1

[0045]Weigh 300.2g of iron phosphate, 76.89g of lithium carbonate and 40g of glucose into an ultra-fine stirring mill, add 1600ml of deionized water, mix with an ultra-fine stirring mill, and then spray dry and granulate at 300°C , to obtain the lithium iron phosphate precursor, and then sintering at 550 ° C, heat preservation for 6 hours, to obtain the pre-lithium iron phosphate positive electrode material for use; weigh 2.902g ammonium dihydrogen phosphate, 2.285g vanadium pentoxide, and 5.7304g oxalic acid respectively in a beaker , 80ml of absolute alcohol was measured in the beaker in advance, and it was mixed with ultrasonic assisted stirring, and then vacuum-dried at 100°C, sintered at 750°C, and kept for 8 hours to obtain VPO 4 The intermediate is standby; then weigh 0.6552g lithium fluoride and the VPO obtained above 4 Intermediate and 76g pre-lithium iron phosphate positive electrode material, composite material mass ratio (lithium iron phosphate: lithium vanadium ph...

Embodiment 2

[0048] Weigh 300.2g of iron phosphate, 76.89g of lithium carbonate and 40g of glucose into an ultra-fine stirring mill, add 1600ml of deionized water, mix with a stirring mill at 300r / min for 4h, and then spray dry at 300°C Granulation treatment to obtain the lithium iron phosphate precursor, followed by sintering at 550°C and heat preservation for 6 hours to obtain the lithium iron phosphate phase material for use; weigh 1.4451g ammonium dihydrogen phosphate, 1.1425g vanadium pentoxide, and 2.8652g oxalic acid respectively in In the beaker, 50ml of absolute alcohol was measured in advance in the beaker, and it was mixed with ultrasonic-assisted stirring, and then vacuum-dried at 100°C, sintered at 750°C, and kept for 8 hours to obtain VPO 4 The intermediate is standby; then weigh 0.3276g lithium fluoride and the VPO obtained above 4 The intermediate and 18g of pre-lithium iron phosphate positive electrode material, the mass ratio of the composite material (lithium iron phosph...

Embodiment 3

[0052] Weigh 300.2g of iron phosphate, 76.89g of lithium carbonate and 40g of glucose into an ultra-fine stirring mill, add 1600ml of deionized water, mix with an ultra-fine stirring mill, and then spray dry and granulate at 300°C , to obtain the lithium iron phosphate precursor, and then sintering at 550 ° C, heat preservation for 6 hours, to obtain the pre-lithium iron phosphate positive electrode material for use; weigh 1.4451g ammonium dihydrogen phosphate, 1.1425g vanadium pentoxide, and 2.8652g oxalic acid respectively in a beaker , 50ml of absolute alcohol was measured in the beaker in advance, and it was mixed with ultrasonic assisted stirring, and then vacuum-dried at 100°C, sintered at 750°C, and kept for 8 hours to obtain VPO 4 The intermediate is standby; then weigh 0.3276g lithium fluoride and the VPO obtained above 4 Intermediate and 8g pre-lithium iron phosphate positive electrode material, composite material mass ratio (lithium iron phosphate: lithium vanadium ...

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Abstract

The invention provides a lithium iron phosphate / lithium vanadium phosphate / carbon composite positive electrode material and a preparation method thereof, the molecular formula of which is (1-x)LiFePO 4 ·xLiVPO 4 F / C, where x=5-40wt%, and the mass fraction of C in the composite cathode material is 0.5-2.0wt%. The present invention first synthesizes lithium iron phosphate, and then synthesizes VPO 4 Intermediate, finally lithium iron phosphate, VPO 4 The intermediate is mixed with other raw materials for the synthesis of lithium vanadium phosphate, and then pressed and sintered to ensure that there is no heterophase formation of lithium vanadium phosphate in the composite material, and a composite structure with a dual-phase lithium intercalation active material is formed in the composite material to stabilize phosphoric acid The surface properties of iron-lithium materials can improve the surface / interface diffusion capacity of lithium ions and the transport rate of electrons, and improve their rate performance and cycle performance without sacrificing energy density.

Description

technical field [0001] The invention belongs to the technical field of cathode materials for lithium ion batteries, and in particular relates to a lithium iron phosphate / lithium fluorovanadium phosphate / carbon composite cathode material and a preparation method thereof. Background technique [0002] Lithium iron phosphate (LiFePO 4 ) has the advantages of good safety performance, environmental friendliness, low cost, high theoretical capacity, and good cycle performance, and is considered to be one of the best cathode materials for lithium-ion power batteries. However, LiFePO 4 Inherent defects such as low electronic conductivity and Li-ion diffusion coefficient lead to poor charge-discharge performance under high-rate conditions. In order to further improve the LiFePO 4 The electrochemical performance is usually optimized by means of metal ion doping and surface conductive coating. Although carbon coating is beneficial to the improvement of the electrochemical performan...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/0525
CPCH01M4/362H01M4/5825H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 曹雁冰胡国荣彭忠东杜柯甘掌根黄勇李唯
Owner 宜宾天原锂电新材有限公司
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