Anion-cation double-doped lithium iron phosphate anode material and preparation method thereof

A lithium iron phosphate, cation technology, applied in battery electrodes, electrical components, circuits, etc., to achieve large ionic conductivity, improve electrochemical performance, and reduce blocking effects

Inactive Publication Date: 2013-12-11
上海微纳科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since magnesium and fluorine are used to replace the positions of iron ions and phosphate radicals in lithium iron phosphate crystals, the transmission of lithium ions in l

Method used

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  • Anion-cation double-doped lithium iron phosphate anode material and preparation method thereof
  • Anion-cation double-doped lithium iron phosphate anode material and preparation method thereof
  • Anion-cation double-doped lithium iron phosphate anode material and preparation method thereof

Examples

Experimental program
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Example Embodiment

[0034] Example 1

[0035] Add 0.097 mol of lithium carbonate, 0.092 mol of ferrous oxalate, 0.004 mol of magnesium nitrate, 0.099 mol of lithium dihydrogen phosphate, 0.003 mol of lithium fluoride and 14 g of citric acid into the ball mill jar, and ball mill at a speed of 280 r / min 8 hours. After the ball-milled mixture is dried, it is ground into a powder. The powder is pre-fired at 400 degrees Celsius for 6 hours under the protection of argon, fired at 700 degrees Celsius for 8 hours, and then naturally cooled to room temperature to obtain anion-cation double-doped lithium iron phosphate, the molecular formula is LiFe 0.92 Mg 0.08 (PO 4 ) 0.99 f 0.03 / C. The measured capacities of the material at 1C, 5C, and 10C rates are 154 mAh / g, 120 mAh / g, and 98 mAh / g, respectively, and the capacity retention rate after 150 cycles at 1C rate is 98.4%.

Example Embodiment

[0036] Example 2

[0037] Add 0.094 mol of lithium nitrate, 0.095 mol of ferrous oxalate, 0.005 mol of magnesium nitrate, 0.098 mol of lithium dihydrogen phosphate, 0.006 mol of lithium fluoride and 17 g of citric acid into the ball mill tank, and ball mill at a speed of 250 r / min 8 hours. After the ball-milled mixture is dried, it is ground into a powder. The powder is pre-fired at 300 degrees Celsius for 4 hours under the protection of argon, fired at 650 degrees Celsius for 10 hours, and then naturally cooled to room temperature to obtain anion and cation double-doped lithium iron phosphate, the molecular formula is LiFe 0.95 Mg 0.05 (PO 4 ) 0.98 f 0.06 / C. The measured capacities of the material at 1C, 5C, and 10C rates are 149 mAh / g, 116 mAh / g, and 93 mAh / g, respectively, and the capacity retention rate after 150 cycles at 1C rate is 98.2%.

Example Embodiment

[0038] Example 3

[0039] Add 0.085 mol of lithium carbonate, 0.090 mol of ferrous oxalate, 0.010 mol of magnesium nitrate, 0.095 mol of lithium dihydrogen phosphate, 0.015 mol of lithium fluoride and 17 g of sucrose into the ball milling tank, and ball mill for 8 hours at a speed of 300 r / min. Hour. After the ball-milled mixture is dried, it is ground into a powder. The powder is pre-fired at 400 degrees Celsius for 6 hours under the protection of argon, fired at 750 degrees Celsius for 12 hours, and then naturally cooled to room temperature to obtain anion and cation double-doped lithium iron phosphate, the molecular formula is LiFe 0.9 Mg 0.1 (PO 4 ) 0.95 f 0.15 / C. The measured capacities of the material at 1C, 5C, and 10C rates are 150 mAh / g, 112 mAh / g, and 86 mAh / g, respectively, and the capacity retention rate after 150 cycles at 1C rate is 97.9%.

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Abstract

The invention discloses an anion-cation double-doped lithium iron phosphate anode material and a preparation method thereof, and belongs to the field of new energy materials. The anode material is a compound of magnesium-fluorine double-doped lithium iron phosphate and carbon, the magnesium ion part replaces the position of a iron ion in a lithium iron phosphate crystal, and the fluoride ion part replaces the position of a phosphoric acid ion in the lithium iron phosphate; main components of the anode material can be expressed as follows: LiFe(1-x)Mgx(PO4)(1-y)F3y/C, wherein x is equal to or greater than 0.001 and is equal to or less than 0.1, and y is equal to or greater than 0.001 and is equal to or less than 0.1. The anode material is prepared by using raw materials of lithium sources, ferrous sources, phosphorus sources, magnesium sources, fluorine sources and carbon sources through a high temperature solid phase method. According to the invention, positive active materials adopts the characteristics of high rate capability, good cycling performance, and the like of a positive active material, so that the capacity remains 98 mAh/g under 10C multiplying power, and the capacity retention ratio remains 98.4% under 1C multiplying power for the circulation of 150 times.

Description

technical field [0001] The invention relates to a lithium ion battery cathode material, in particular to an anion-cation double-doped modified lithium iron phosphate cathode material and a preparation method thereof, belonging to the technical field of new energy materials. technical background [0002] Cathode material is an important part of lithium-ion batteries, and it is also one of the key factors restricting the development of lithium-ion batteries. The currently widely used cathode material for lithium-ion batteries is layered LiCoO 2 , but due to its scarcity of raw materials, high price and high toxicity, it is very important to find a substitute for LiCoO 2 The requirements for cathode materials are getting stronger and stronger. In 1997, Goodenough et al first reported lithium iron phosphate (LiFePO 4 ) has the property of reversible desorption and intercalation of lithium ions, which has attracted great attention. Compared to LiCoO 2 , the material has the ...

Claims

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Application Information

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IPC IPC(8): H01M4/58H01M4/62
CPCY02E60/10
Inventor 徐云龙黄永安
Owner 上海微纳科技有限公司
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