Lithium ion battery silicon-based cathode composite binder, preparation method and application thereof

A lithium-ion battery, silicon-based negative electrode technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of low viscosity and unsuitability of polyionic liquids, improve strain performance, improve bonding effect, and improve cycle. The effect of stability

Active Publication Date: 2019-07-30
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, polyionic liquids can also be used as binder materials for lithium-ion batteries (Journal of Power Sources 2013,240,745-752), and compared with traditional binder materials, polyionic liquids have good ionic conductivity and have It is conducive to the diffusion and transmission of lithium ions in the electrode material, and reduces the internal resistance of the battery, thereby improving the specific capacity and cycle stability of the battery. However, the polyionic liquid itself has a low viscosity and is not suitable for use alone in the silicon negative electrode of lithium-ion batteries. Binder

Method used

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  • Lithium ion battery silicon-based cathode composite binder, preparation method and application thereof
  • Lithium ion battery silicon-based cathode composite binder, preparation method and application thereof
  • Lithium ion battery silicon-based cathode composite binder, preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Embodiment 1 prepares polyionic liquid (PIL / TFSI)

[0033] (1) Acetic acid (4mL) and 2,2'-(ethylenedioxy)bis(ethylamine) (4.89g, 33mmol) were dissolved in deionized water (10mL) to obtain solution A, which was added to a round bottom flask, The round bottom flask was placed in an ice-water bath; then formaldehyde (2.5ml) and glyoxal (4.85ml) were mixed in advance to obtain solution B, and solution B was added dropwise to the above round bottom flask under stirring to obtain solution C;

[0034] (2) After the dropwise addition, transfer the round-bottomed flask to an oil bath, condense and reflux the solution C at 100°C for 1 hour, then cool the entire reaction device at room temperature, and distill under reduced pressure at 80°C to remove excess solvent and reactant, and washed several times with acetone to obtain the product PIL / AcO with a yield of 81%. ;

[0035] (3) Dissolve 2g LiTFSI in 100mL water to obtain a LiTFSI solution, dissolve 1g PIL / AcO prepared in step...

Embodiment 2

[0044] Example 2 with PAAH 0.8 – Li 0.2 Preparation of Lithium Batteries with Composite Binder of PIL / TFSI

[0045] Weigh PAAH according to the mass ratio of 3:1 0.8 – Li 0.2 (average molecular weight 450,000) and PIL / TFSI, dissolve it in DMSO solvent, heat and evaporate to remove the solvent, and obtain a composite binder; then nano-silicon particles, conductive agent carbon black (Super-P) and composite binder The binder is dispersed in NMP with a mass ratio of 8:1:1, and a uniform slurry is formed by grinding and stirring, and coated on the copper foil. Then place the pole pieces in a drying oven, dry them at 80°C for 36 hours, cut them into circular electrode pieces with a diameter of 1 cm, and store them in a glove box. A lithium sheet was used as the counter electrode to assemble a 2032 button cell. Among them, the electrolyte uses 1M LiPF 6 It is an EC / DMC / DEC solution with a volume ratio of lithium salt of 1:1:1. The assembled battery is left to stand for 12 hour...

Embodiment 3

[0046] Example 3 with PAAH 0.8 – Li 0.2 Preparation of Lithium Batteries with Composite Binder of PIL / TFSI

[0047] Weigh PAAH according to the mass ratio of 2:1 0.8 – Li 0.2 (average molecular weight 450,000) and PIL / TFSI, dissolve it in NMP solvent, heat and evaporate to remove the solvent, and obtain a composite binder; then nano-silicon particles, conductive agent carbon black (Super-P) and composite bond The agent is dispersed in NMP with a mass ratio of 8:1:1, and a uniform slurry is formed by grinding and stirring, and coated on copper foil. Then place the pole piece in a drying oven, dry it at 80°C for 36h, then cut it into a circular electrode piece with a diameter of 1cm, and store it in a glove box. A lithium sheet was used as the counter electrode to assemble a 2032 button cell. Among them, the electrolyte uses 1M LiPF 6 It is an EC / DMC / DEC solution with a volume ratio of lithium salt of 1:1:1. The assembled battery is left to stand for 12 hours, and the batt...

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Abstract

The invention discloses a lithium ion battery silicon-based cathode composite binder, a preparation method and application thereof. The composite binder comprises modified polyacrylic acid and polyionliquid, wherein the molecular formula of the modified polyacrylic acid is abbreviated as PAAH<1-X>-Li<X>; the polyion liquid PIL/TFSI contains di(trifluoromethyl sulfonyl) imide anions. The compositebinder combines the excellent binding performance of polyacrylic acid and the good ionic conductivity of polyion liquid, and is beneficial to the diffusion and transmission of lithium ions in a silicon negative electrode; in addition, since the PIL/TFSI used in the method has low glass transition temperature and good flexibility, the strain performance of PAAH<1-X>-Li<X> is effectively improved,which is suitable for the expansion of the volume of the silicon cathode and improves the cycling stability of the silicon cathode. The silicon-based cathode material of the lithium ion battery prepared by the composite binder can effectively reduce the internal resistance of lithium ion transmission and effectively improve the cycle stability of the battery.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and in particular relates to a silicon-based negative electrode composite binder for lithium-ion batteries and a preparation method and application thereof. Background technique [0002] Lithium-ion batteries have been widely used in various electronic devices and electric vehicles. How to construct lithium-ion batteries with high energy density, high safety and reliability, and excellent cycle stability is still a major problem that researchers need to overcome. problem (Nature 2001, 414, 359–367). Lithium-ion batteries are mainly composed of positive and negative electrode layers and an intermediate electrolyte layer, and the negative electrode is the main component of lithium-ion batteries. At present, lithium-ion batteries generally use graphite anodes, which have low gram capacity and safety risks such as lithium metal precipitation, while new silicon-based anode materials have higher g...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M10/0525
CPCH01M4/622H01M10/0525Y02E60/10
Inventor 郭盼龙林少雄蔡桂凡毕超奇谢李昭石永倩杨立铭高玉仙
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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