Bi-imidazole ring functional ionic liquid, preparing method thereof, electrolyte and lithium secondary battery

A technology of functional ionic liquid and biimidazole ring, applied in secondary batteries, non-aqueous electrolyte batteries, lithium batteries, etc., can solve the problems of affecting conductivity, electrochemical window compatibility, affecting battery performance, and large interface impedance, etc. Achieve high practical application value, improve safety, and effect of high thermodynamic stability

Active Publication Date: 2019-05-21
XIAMEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Ionic liquid-based gel polymer electrolytes combine the advantages of ionic liquids such as safety, high conductivity, and wide applicable temperature range, as well as the self-supporting and flexible properties of polymer electrolytes, but also have large interface impedance and low battery capacity. Problems such as poor performance and poor magnification performance
[0006] In fact, regardless of the application method, the selection of anions and cations in ionic liquids is a key issue, because the structure of anions and cations will directly affect properties such as conductivity, electrochemical window, and compatibility with electrode materials, thereby affecting battery performance.

Method used

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  • Bi-imidazole ring functional ionic liquid, preparing method thereof, electrolyte and lithium secondary battery
  • Bi-imidazole ring functional ionic liquid, preparing method thereof, electrolyte and lithium secondary battery
  • Bi-imidazole ring functional ionic liquid, preparing method thereof, electrolyte and lithium secondary battery

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Effect test

Embodiment 1

[0045] Embodiment 1: Biimidazole ring functional ionic liquid Im 2 -TFSI 2 and a single ionic liquid electrolyte and graphite half-cell

[0046] The double imidazole ring functional ionic liquid Im involved in the present embodiment 2 -TFSI 2 prepared as figure 1 As shown, the specific steps are as follows:

[0047] (1) Add 50mL of acetonitrile and 0.2mol N-methylimidazole into a three-necked flask, put in a magnet, heat and magnetically stir in an oil bath at 80°C, reflux and condense, and nitrogen gas is introduced. After 30min, use a constant pressure funnel to Add 0.12mol 2,2'-dichloroethylether dropwise and react for 24 hours; pour the reaction product into a round-bottomed flask, and evaporate at 60°C for more than 2 hours, then place the product in a vacuum oven at 60°C for more than 24 hours to obtain intermediate product, named Im 2 -Cl 2 ;

[0048] (2) Take 0.05mol Im 2 -Cl 2 Dissolve in 25mL deionized water, stir well; another 0.12mol LiTFSI is dissolved i...

Embodiment 2

[0055] Embodiment 2: Biimidazole ring functional ionic liquid Im 2 -TFSI 2 and multicomponent ionic liquid electrolytes and graphite half-cells

[0056] The double imidazole ring functional ionic liquid Im involved in the present embodiment 2 -TFSI 2 The preparation method is with embodiment 1.

[0057] This embodiment utilizes double imidazole ring functional ionic liquid Im 2 -TFSI 2 As a functional additive of conventional imidazole-type ionic liquid EMIm-TFSI (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide), it can not only improve the stability of the ionic liquid electrolyte, but also reduce the Increase the viscosity, increase the conductivity, and play a synergistic role among multiple ionic liquids. Specifically, the preparation method of the multiple ionic liquid electrolyte and graphite battery involved in this embodiment is as follows:

[0058] In an argon glove box, mix 1mL EMIm-TFSI with 100uL, 300uL, 500uL, 800uL and 1mL Im 2 -TFSI 2 Mix ...

Embodiment 3

[0060] Embodiment 3: Biimidazole ring functional ionic liquid Im 2 -TFSI 2 and gel polymer electrolytes and LiFePO 4 half cell

[0061] The double imidazole ring functional ionic liquid Im involved in the present embodiment 2 -TFSI 2 The preparation method is with embodiment 1.

[0062] The gel polymer electrolyte involved in this embodiment contains 26wt% PVDF-co-HFP and 74wt% (Im 2 -TFSI 2 +1mol / kg vs. m ILs LiTFSI), the preparation process is as follows:

[0063] (1) Synthesis of Biimidazole Ring Functional Ionic Liquid Im 2 -TFSI 2 : same as synthetic steps in embodiment 1;

[0064] (2) Prepare the solution: weigh 0.73g PVDF-co-HFP in an argon atmosphere glove box and dissolve it in 15mL ethylene glycol dimethanol (DME). After the dissolution is complete, add 1.6g Im 2 -TFSI 2 and 0.46g LiTFSI, magnetically stirred for 12h;

[0065] (3) Solvent volatilization: Take 5mL of the above solution and pour it into a 5cm×7cm polytetrafluoroethylene mold, first volati...

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Abstract

The invention belongs to the field of batteries, and discloses a bi-imidazole ring functional ionic liquid, a preparing method thereof, an electrolyte and a lithium secondary battery. The di-imidazolering functional ionic liquid comprises divalent cations with bi-imidazole rings and ether group functional groups and two anions. The bi-imidazole ring functional ionic liquid has higher thermodynamic stability, electrochemical stability and positive and negative electrode compatibility. Moreover, the preparing method is simple, the product is high in purity and good in hydrophobicity, the thermal decomposition temperature can reach 430 DEG C, the room-temperature conductivity can reach 10<-4>S/cm, the electrochemical window can reach 5.6V vs.Li/Li+, and the safety of the lithium secondary battery can be improved. A bi-imidazole ring ionic liquid electrolyte can effectively inhibit reductive decomposition of imidazolium cations on a graphite negative electrode specially in a graphite negative electrode system, a stable SEI membrane can be formed without addition of any low-boiling-point film-forming additive, so that the battery can be stably circulated under the conditions of normaltemperature and high temperature, and has very high practical application value.

Description

technical field [0001] The invention belongs to the field of batteries, and in particular relates to a biimidazole ring functional ionic liquid, a preparation method thereof, an electrolyte solution, and a lithium secondary battery. Background technique [0002] With the increasing demand for new energy vehicles, portable electronic devices and flexible devices, people have higher and higher requirements for the safety, energy density and power density of lithium secondary batteries. In recent years, incidents such as spontaneous combustion and explosion of electric vehicles and mobile phones have occurred frequently, which are mainly caused by the fact that traditional liquid organic electrolytes are easy to decompose, volatile and flammable. Therefore, ionic liquid electrolytes and solid electrolytes with high safety have become a research hotspot. [0003] Ionic liquids are room temperature molten salts composed of anions and cations. They have the advantages of non-vola...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D233/60C07F5/02C07F9/535H01M10/052H01M10/0565H01M10/0569
CPCY02E60/10
Inventor 董全峰郑明森范镜敏段佳宁
Owner XIAMEN UNIV
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