Non-stoichiometric lithium iron manganese phosphate positive electrode material as well as preparation method and application thereof

A non-stoichiometric technology of lithium manganese iron phosphate, which is applied in the field of lithium-ion batteries, can solve problems such as difficult control and sensitive synthesis conditions, and achieve easy control of the process, improvement of electrochemical performance, discharge specific capacity and cycle stability. Effect

Active Publication Date: 2021-07-23
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method of regulating surface phase impurities is very sensitive to synthesis conditions and is not easy to control

Method used

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  • Non-stoichiometric lithium iron manganese phosphate positive electrode material as well as preparation method and application thereof
  • Non-stoichiometric lithium iron manganese phosphate positive electrode material as well as preparation method and application thereof
  • Non-stoichiometric lithium iron manganese phosphate positive electrode material as well as preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] (1) Lithium dihydrogen phosphate (2.0786g), ferrous oxalate dihydrate (1.7989g), manganese carbonate (1.1495g), lithium carbonate (0.0369g), sucrose (0.1885g), polyvinyl alcohol (0.1885g) Place in a zirconia ball mill jar filled with 30 g of absolute ethanol and 1.5 g of oleic acid, and ball mill at a speed of 400 r / min for 8 hours to obtain a suspension;

[0050] (2) Centrifuge the suspension in step (1), and vacuum-dry the obtained solid mixture at 80° C. for 1 hour to obtain a precursor;

[0051] (3) The precursor powder obtained in step (2) was placed in a tube furnace with an argon atmosphere, the temperature was raised to 420° C. for pre-calcination for 5 hours, and then the temperature was raised to 650° C. for 8 hours. get Li 1.05 Fe 0.5 mn 0.5 PO 4 / C cathode material (the non-stoichiometric lithium manganese iron phosphate cathode material).

[0052] Such as figure 1 Shown is the rate performance diagram of the material prepared in Example 1 under differ...

Embodiment 2

[0057] (1) Lithium dihydrogen phosphate (2.0786g), ferrous oxalate dihydrate (1.7089g), manganese carbonate (1.1495g), lithium carbonate (0.0369g), sucrose (0.1885g), polyvinyl alcohol (0.1885g) Place in a zirconia ball mill jar filled with 30 g of absolute ethanol and 1.5 g of oleic acid, and ball mill at a speed of 400 r / min for 8 hours to obtain a suspension;

[0058] (2) Centrifuge the suspension in step (1), and vacuum-dry the obtained solid mixture at 80° C. for 1 hour to obtain a precursor;

[0059] (3) The precursor powder obtained in step (2) was placed in a tube furnace with an argon atmosphere, the temperature was raised to 420° C. for pre-calcination for 5 hours, and then the temperature was raised to 650° C. for 8 hours. get Li 1.05 Fe 0.475 mn 0.5 PO 4 / C cathode material (the non-stoichiometric lithium manganese iron phosphate cathode material).

[0060] Such as figure 1 Shown is the rate performance diagram of the material prepared in Example 2 under diff...

Embodiment 3

[0065] (1) Lithium dihydrogen phosphate (2.0786g), ferrous oxalate dihydrate (1.7989g), manganese carbonate (1.0920g), lithium carbonate (0.0369g), sucrose (0.1885g), polyvinyl alcohol (0.1885g) Place in a zirconia ball mill jar filled with 30 g of absolute ethanol and 1.5 g of oleic acid, and ball mill at a speed of 400 r / min for 8 hours to obtain a suspension.

[0066] (2) The suspension in step (1) was centrifuged, and the obtained solid mixture was vacuum-dried at 80° C. for 1 hour to obtain a precursor.

[0067] (3) The precursor powder obtained in step (2) was placed in a tube furnace with an argon atmosphere, the temperature was raised to 420° C. for pre-calcination for 5 hours, and then the temperature was raised to 650° C. for 8 hours. get Li 1.05 Fe 0.5 mn 0.475 PO 4 / C cathode material (the non-stoichiometric lithium manganese iron phosphate cathode material).

[0068] Such as figure 1 As shown, the first discharge specific capacity of the material prepared in...

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Abstract

The invention discloses a non-stoichiometric lithium iron manganese phosphate positive electrode material as well as a preparation method and application thereof. The lithium iron manganese phosphate positive electrode material has a chemical general formula of Li < 1 + 2x > (FeMn) < 1-x > PO4/C, wherein x is greater than 0.015 and less than 0.035. The method comprises the steps of mixing lithium dihydrogen phosphate, ferrous oxalate, manganese carbonate, lithium carbonate, cane sugar and polyvinyl alcohol, ball-milling, centrifuging and drying to obtain a precursor; and heating in an inert atmosphere and calcining to obtain the non-stoichiometric lithium iron manganese phosphate positive electrode material. According to the method, a non-stoichiometric ratio method is adopted, the total number of cation valences is kept unchanged, other ions are not doped, and the material is doped with a small amount of lithium. According to the method, lattice parameters of the positive electrode material can be regulated and controlled, the particle sizes of primary and secondary particles are reduced, a small quantity of second-phase ionic conductors are generated, and the electrochemical performance of the material is synergistically improved. The method is low in raw material cost, simple in process and convenient for large-scale production.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a non-stoichiometric lithium manganese iron phosphate positive electrode material and a preparation method and application thereof. Background technique [0002] The emergence of lithium-ion batteries has alleviated today's serious energy and environmental problems to a certain extent, and has been widely used in daily life because of its advantages such as high energy density, long life, and no memory effect. In order to reduce dependence on non-renewable energy sources such as petroleum and reduce exhaust emissions, new energy vehicles have developed rapidly in recent years. As a key component of batteries, cathode materials have become the key to restricting the performance of power batteries. [0003] The olivine-type lithium manganese iron phosphate cathode material is developed on the basis of the same olivine-type lithium iron phosphate and lithium manganes...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/583H01M10/0525
CPCH01M4/366H01M4/5825H01M4/583H01M10/0525H01M2004/028Y02E60/10
Inventor 邓远富王杰
Owner SOUTH CHINA UNIV OF TECH
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