Cathode material LiMn1-xFexPO4 for lithium ion cell and preparation method of cathode material LiMn1-xFexPO4

A lithium iron manganese phosphate and lithium ion battery technology, applied in battery electrodes, chemical instruments and methods, circuits, etc., can solve problems such as poor cyclability, capacity fading, core-shell structure interface separation, etc., and achieve excellent rate performance and cycle performance. Good, high energy density effect

Active Publication Date: 2015-04-29
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Abstract
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AI Technical Summary

Problems solved by technology

However, its actual specific capacity, ion / electronic conductivity, cycle performance and rate performance are inferior to those of lithium iron phosphate, which seriously hinders the commercialization of lithium manganese phosphate.
The development of lithium manganese iron phosphate, which combines the advantages of lithium manganese phosphate and lithium iron phosphate, is currently a hot spot in energy development, but manganese ions are easily dissolved in the electrolyte, resulting in structural collapse, serious capacity attenuation and poor cycle performance. , so there is an urgent need to improve the cycleability of lithium manganese iron phosphate
Some papers have reported lithium manganese iron phosphate core-shell structure materials coated with lithium iron phosphate. The core-shell can avoid the occurrence of problems such as manganese dissolution, structural instability and serious capacity decay caused by direct contact of manganese with the electrolyte. After that, the core-shell structure interface separation phenomenon will occur, which affects the life of the material.

Method used

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  • Cathode material LiMn1-xFexPO4 for lithium ion cell and preparation method of cathode material LiMn1-xFexPO4
  • Cathode material LiMn1-xFexPO4 for lithium ion cell and preparation method of cathode material LiMn1-xFexPO4

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Embodiment 1

[0025] (1) Preparation of reaction solution

[0026] Preparation of 0.5 mol / L manganese-rich solution A: Dissolve manganese oxalate and ferrous oxalate in deionized water at a molar ratio of 5:1;

[0027] Prepare 0.5 mol / L manganese-poor solution B: dissolve manganese oxalate and ferrous oxalate in deionized water at a molar ratio of 0.05:1;

[0028] Prepare 0.5 mol / L phosphorus source solution C: dissolve ammonium dihydrogen phosphate in deionized water;

[0029] (2) Add the manganese-poor solution B in step (1) to the manganese-rich solution A at a rate of 1 L / h. After mixing evenly, add the mixed solution to the phosphorus source solution C, and control the concentration of metal ions in the mixed solution. The molar ratio of phosphorus source is 1:1, under the protection of nitrogen, stir, heat at 50 ℃ for 20 h, wash and dry, and obtain the precursor of ferromanganese phosphate with gradient structure, and the precursor is from the inside to the outside along the particle...

Embodiment 2

[0033] (1) Preparation of reaction solution

[0034] Prepare 5 mol / L manganese-rich solution A: dissolve manganese chloride and ferrous chloride in deionized water at a molar ratio of 9:1;

[0035] Prepare 5 mol / L manganese-poor solution B: dissolve manganese chloride and ferrous chloride in deionized water at a molar ratio of 1:1;

[0036] Prepare 5 mol / L phosphorus source solution C: dissolve ammonium dihydrogen phosphate in deionized water;

[0037] (2) Add the manganese-poor solution B in step (1) to the manganese-rich solution A at a rate of 3 L / h. After mixing evenly, add the mixed solution to the phosphorus source solution C to control the concentration of metal ions in the mixed solution. The molar ratio to the phosphorus source is 1:1, stirred under the protection of nitrogen, heated at 100 °C for 5 h, washed and dried, and the precursor of ferromanganese phosphate with gradient structure is obtained. The precursor is from the inside to the inside along the particle ...

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Abstract

The invention discloses a cathode material LiMn1-xFexPO4 for a lithium ion cell and a preparation method of the cathode material LiMn1-xFexPO4. The preparation method comprises the following steps: manganese source compounds and iron source compounds are adopted as the raw materials to prepare manganese-rich solution and a manganese-poor solution respectively, a FeMnPO4 precursor with a gradient structure is synthesized through a coprecipitation method by controlling the sample adding speed, and then lithium doping and high-temperature calcination are performed to prepare the LiMn1-xFexPO4 with a gradient structure, that is the manganese content of the LiMn1-xFexPO4 is gradually reduced while the iron content of the LiMn1-xFexPO4 is gradually increased from inside to outside along the particle radius of the LiMn1-xFexPO4. The anode material LiMn1-xFexPO4 with the gradient structure has the characteristics of high energy density, good cycle performance and excellent rate capability and is applied to the field of application of power lithium-ion batteries.

Description

technical field [0001] The invention relates to lithium manganese iron phosphate lithium ion battery cathode material and a preparation method thereof. Background technique [0002] Lithium-ion power battery is a high-energy battery that has been developed rapidly in the past five years. It has significant advantages such as long life, high energy density and high voltage platform. It has become an important direction for the development of my country's new energy industry. [0003] Cathode materials are an important part of power batteries. Lithium manganese phosphate cathode material with olivine structure is considered to be one of the most promising next-generation candidate cathode materials due to its high voltage platform, high mass energy density, environmental friendliness, and stable structure and performance, and is expected to be applied to Electric vehicle (EV) field. However, its actual specific capacity, ion / electronic conductivity, cycle performance, and ra...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58C01B25/45
CPCC01B25/45H01M4/5805Y02E60/10
Inventor 王启岁邢军龙张昌春
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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