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Positive electrode active material, positive electrode containing the positive electrode active material, and lithium secondary battery

A lithium secondary battery, content technology, applied in battery electrodes, circuits, electrical components, etc., can solve problems such as residual impurities and incomplete reaction products

Active Publication Date: 2021-02-26
BEIJING TAIFENG XIANXING NEW ENERGY TECH CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

All of these properties are difficult to control in a very precise manner during the reaction, which can lead to non-stoichiometric products, incomplete reactions, or residual impurities in the products

Method used

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  • Positive electrode active material, positive electrode containing the positive electrode active material, and lithium secondary battery
  • Positive electrode active material, positive electrode containing the positive electrode active material, and lithium secondary battery
  • Positive electrode active material, positive electrode containing the positive electrode active material, and lithium secondary battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0239] Weigh FePO 4 2H 2 O (200g, from Changsha Hekang Chemical Company, battery grade, D 90 2.92μm), Li 2 CO 3 (molar ratio 2:1, from Chengdu Chemical Chemical Company, battery grade, D 90 2.84μm), Brij 35 (accounting for FePO 4 2H 2 3.5 wt% of O from Croda), and deoxygenated isopropanol (accounting for FePO 4 2H 2 50wt% of O) was added to a zirconia cylindrical container equipped with 5mm zirconia balls, wherein the weight ratio of balls / powder materials was 2:1. In a Retsch model PM100 planetary ball mill, the ball milled for 30 minutes at a speed of 400 rpm under an argon atmosphere. After grinding, the slurry was evaporated to dryness at 80 °C. Then, according to the method disclosed in US2002 / 0195591 A1, the mixture was heated to 600° C. at a heating rate of 10° C. / min in a tube furnace (Zhengzhou CY Scientific Instrument Co., Ltd.) with a dry deoxygenated nitrogen gas stream, and at this temperature Keep warm for 60min.

[0240] A carbon deposition material w...

Embodiment 2

[0254] As in Example 1, repeat the synthetic process of material-a1, different batches of FePO 4 2H 2 O (500g FePO for each synthesis 4 2H 2 O), then nano-grinding with 200 μm yttrium-stabilized zirconia balls in an alcohol base for 90 min, followed by spray-drying of the suspension.

[0255] For each batch, 300g of nanomaterials were placed in the furnace tube of a rotary kiln (Zhengzhou CY Scientific Instrument Company, model CY-R200X-100IC), and dry nitrogen was introduced into the furnace tube, and the temperature was raised to 200 °C at a heating rate of 10 °C / min. ℃, keep warm for 60min, and then continuously feed the mixed gas of vaporized benzene and argon (containing 3% benzene by volume). After heating up to 640°C at a rate of 20°C / min, the temperature was kept for 1 hour to obtain carbon-deposited LiFePO 4 . The sulfur content and carbon content in each batch were determined by the combustion analysis method with a carbon / sulfur analyzer (LECO Company), and the...

Embodiment 3

[0279] As in Example 1, with high-purity FePO 4 2H 2 O (100kg), battery-grade Li 2 CO 3 (molar ratio 1:2), Pluronic P-123 (relative to FePO 4 2H 2 O 2wt.%; Polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer, produced by BASF) Repeat the synthesis process of material-a1. The precursors were ground in 200 L of degassed methanol using a MasterMill model 18 basket mill (from Netzsch). After the solvent evaporated, the material (referred to as material-a3) was placed in a ceramic crucible, placed in a roller kiln blown in dry oxygen-free nitrogen, and treated at 600 °C for 60 minutes, then cooled and stored in nitrogen.

[0280] A carbon deposition material with a carbon content of 0.35wt% (measured by LECO) was obtained, and its composition was determined to contain 73.7wt% LiFePO by XRD analysis. 4 , Li3PO4 and Fe with a molar ratio of 1:1 remain 3 (PO 4 ) 2 phase, with Spectral analysis showed no Fe(III).

[0281] A 2 Kg batch of material...

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Abstract

The invention relates to a positive electrode active material, a positive electrode containing the positive electrode active material and a lithium secondary battery. The positive electrode active material is a carbon-deposited alkali metal oxyanion, and its preparation method includes: (a) dry or wet grinding the precursor of the alkali metal oxyanion, when wet grinding, drying the ground precursor to obtain solid compound; then heat-treat the ground precursor in a protective atmosphere to obtain a heat-treated material; (b) the material obtained in step (a) is subjected to microbead nanogrinding in at least one alcohol-based system to obtain nano suspension; (c) drying the nano-suspension obtained in step (b) to obtain a solid compound; (d) placing the solid compound obtained in step (c) in at least one gas-phase carbon source steam, and using a gas-phase The carbon source deposition process yields carbon deposited alkali metal oxyanions. The present invention can be readily applied to fabricate various grades of high-performance and low-cost cathode materials.

Description

technical field [0001] The invention relates to a carbon-deposited alkali metal oxyanion, its multi-step preparation process, and the use of the carbon-deposited alkali metal oxyanion as a positive electrode material for a lithium secondary battery. Background technique [0002] Olivine LiFePO 4 With excellent capacity retention, thermal stability, non-toxicity and safety, it has become an important cathode material for lithium-ion batteries. But the olivine-type LiFePO 4 There are obvious defects such as low intrinsic electronic and ionic conductivity. The electronic conductivity can be improved by carbon coating, and the diffusion of lithium ions can be solved by synthesizing small particles. [0003] In the specific case of carbon-deposited lithium iron phosphate, referred to as C-LiFePO 4 , several processes for fabricating this material have been proposed, either by carbon precursors in LiFePO 4 Thermal decomposition on, or by lithium, iron, PO 4 It is produced by...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/583H01M4/62H01M4/58C01B25/26C01B25/45C01B25/37
CPCY02E60/10
Inventor 雷敏莱东圣郑小建杨新河周恒辉
Owner BEIJING TAIFENG XIANXING NEW ENERGY TECH CO LTD