High-concentration electrolyte for lithium ion battery, preparation method thereof, and lithium ion battery

A lithium-ion battery and electrolyte technology, which is applied in the field of high-concentration electrolyte for lithium-ion batteries and its preparation, to achieve the effects of improving battery energy density, small reaction polarization, and good kinetic characteristics

Inactive Publication Date: 2019-03-08
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In view of this, the technical problem to be solved by the present invention is to provide a high-concentration electrolyte for lithium-ion batteries and its preparation method and lithium-ion batteries, improve the safety of the electrolyte, realize the protection of the aluminum current collector, and reduce the high-c

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  • High-concentration electrolyte for lithium ion battery, preparation method thereof, and lithium ion battery
  • High-concentration electrolyte for lithium ion battery, preparation method thereof, and lithium ion battery
  • High-concentration electrolyte for lithium ion battery, preparation method thereof, and lithium ion battery

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[0042] The present invention also provides a method for preparing the above-mentioned electrolyte, which includes the following steps:

[0043] Under protective atmosphere conditions, mixing non-aqueous solvents and wetting agents to obtain a mixed solution;

[0044] Lithium salt is added to the mixed solution and mixed uniformly to obtain a high-concentration electrolyte for lithium ion batteries.

[0045] In the present invention, a non-aqueous solvent and a wetting agent are first mixed under a protective atmosphere to obtain a mixed solution. Wherein, the protective atmosphere conditions are selected from argon or nitrogen. The present invention has no special restrictions on the mixing method, as long as the mixing method is well known to those skilled in the art.

[0046] Then, lithium salt is added to the mixed solution, and after the lithium salt is completely dissolved and mixed uniformly, a high-concentration electrolyte for lithium ion batteries is obtained.

[0047] In the...

Embodiment 1

[0061] Electrolyte formula: lithium salt lithium hexafluorophosphate (LiPF 6 ), non-aqueous organic solvent dimethyl carbonate (DMC), fluoroethylene carbonate (FEC), wetting agent 1,1,1,3,3,3-hexafluoroisopropyl methyl ether (HFPM).

[0062] Electrolyte preparation method: In a glove box filled with argon, mix DMC, FEC, HFPM with 10mL solvent according to the volume ratio provided in Table 1, and slowly add lithium salt lithium hexafluorophosphate (LiPF 6 ), make the concentration of the lithium salt 3mol / L, and stir until the lithium salt is completely dissolved to obtain an electrolyte.

[0063] Performance test: Determine the viscosity and contact angle of the prepared electrolyte. The results are shown in Table 1 and figure 1 , figure 1 It is the test chart of the contact angle of electrolyte with different formula ratios. figure 1 (A), (b), (c) and (d) in Table 1 correspond to the contact of electrolytes obtained in different ratios of DMC / FEC / HFPM in (a), (b), (c) and (d) in Ta...

Embodiment 2

[0069] Electrolyte formula: lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), non-aqueous organic solvent tetramethylurea, wetting agent 1,1,1,3,3,3-hexafluoroisopropyl Base methyl ether (HFPM):

[0070] Electrolyte preparation method: In a glove box filled with argon, mix tetramethylurea and HFPM with 10mL solvent at a volume ratio of 70:30, and slowly add lithium salt bis(trifluoromethylsulfonyl)imide lithium ( LiTFSI), the concentration of the lithium salt is shown in Table 2. Stir until the lithium salt is completely dissolved to obtain an electrolyte.

[0071] Performance test: Determine the conductivity of the prepared electrolyte, the viscosity of the electrolyte, and the contact angle.

[0072] Table 2 Test results of viscosity, contact angle and conductivity of different electrolytes

[0073]

[0074] Determine the corrosion of aluminum foil in the electrolyte, and see the results Figure 4 , Figure 4 Corrosion of aluminum foil in electrolyte with different formula ratios...

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Abstract

The invention provides a high-concentration electrolyte for a lithium ion battery. The electrolyte comprises lithium salt, a non-aqueous solvent and a wetting agent; the concentration of the lithium salt is higher than 2 mol/L; and the wetting agent is selected from fluoro-ether compounds. The wetting agent is added in the electrolyte, so that the viscosity of the electrolyte is reduced and the wettability is improved while the high concentration is ensured; the dynamic characteristic of the electrochemical reaction on the electrode/electrolyte interface is good, and the reaction polarizationis small. Therefore, the wetting agent is added in the electrolyte so that the safety of the electrolyte can be improved, the protection of an aluminum current collector is realized, the viscosity ofthe high-concentration electrolyte is reduced, and the problem of poor wettability of the electrolyte is solved; and the electrochemical stable voltage of the electrolyte exceeds 4.5V, so the electrolyte is suitable for a high-voltage positive electrode material; the capacity of the battery is fully played; and the energy density of the battery is improved.

Description

Technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and specifically relates to a high-concentration electrolyte for lithium-ion batteries, a preparation method thereof, and a lithium-ion battery. Background technique [0002] Lithium-ion batteries are widely used in portable electronic devices such as consumer electronics and power tools because of their advantages of high energy density and long cycle life, and are popularized in large-scale energy storage fields such as smart grids and electric vehicles. People put forward higher requirements for its energy density, cycle life, and safety. A key factor in improving the energy density of lithium-ion batteries is the development of high-voltage lithium-ion batteries. As a key component of the battery system, the electrolyte determines the current density, cycle stability and safety of the battery, and is a guarantee for the application of high-voltage electrode materials. . At present,...

Claims

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Application Information

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IPC IPC(8): H01M10/0567H01M10/0525
CPCH01M10/0525H01M10/0567H01M2300/0025Y02E60/10
Inventor 陈士庆代文慧骆浩刘兆平
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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