Nonaqueous electrolyte for electrochemical energy storage device and electrochemical energy storage device making use of the same

A non-aqueous electrolyte and energy storage technology, applied in the direction of non-aqueous electrolyte batteries, electrolytic capacitors, electrochemical generators, etc., can solve the problems of damage to the protective film, difficulty in inserting lithium ions, and increased capacity degradation

Inactive Publication Date: 2008-02-27
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

And it has been clear that there is a problem: when charging continues, the layered structure of graphite is destroyed due to the insertion of TEMA ions, so lithium ions are difficult to insert, so the potential of the negative electrode will not become negative.
However, when the charge-discharge cycle is repeated, there is a problem that the protective film is destroyed due to the expansion and contraction of the graphite-based material, so that TEMA ions penetrate into the interlayer of graphite, or the TEMA ions are polarized in the direction of negative potential. reduced by the negative electrode, thus increasing the capacity degradation

Method used

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  • Nonaqueous electrolyte for electrochemical energy storage device and electrochemical energy storage device making use of the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Artificial graphite powder is used as an anode material for intercalation / deintercalation of lithium ions during charge and discharge. The negative electrode plate was produced by the following method. First, 75 parts by mass of artificial graphite powder, 20 parts by mass of acetylene black as a conductive agent, 5 parts by mass of polyvinylidene fluoride resin as a binder, and dehydrated N-methyl-2-pyrrolidone as a dispersion solvent to mix. Next, the mixture was coated on one surface of a 20 μm thick copper foil current collector and dried to form an 80 μm thick active material layer. Then, the copper foil current collector formed with the active material layer was cut into a size of 35 mm × 35 mm, and a copper current collector plate with a lead wire thickness of 0.5 mm was welded to the obtained copper foil current collector by ultrasonic welding. On the body, thereby making the negative electrode plate.

[0036] In addition, the mixed LiBF 4 , EC and TMA·BF 4...

Embodiment 2

[0047] Use ethyl (TMEA ions), propyl (TMPA ions), butyl (TMBA ions), pentyl (TMPeA ions), hexyl (TMHA ions) with sequentially increasing alkyl chain lengths to replace one of the TMA ions Based on quaternary ammonium salts, the effect of alkyl chain length was studied. Anions are fixed as TFSI ions.

[0048] Each electrolyte solution was prepared by mixing LiTFSI, EC, and each quaternary ammonium salt at a molar ratio of 0.6 / 4 / 0.6.

[0049] In the same manner as in Example 1, a negative plate with artificial graphite powder was used as a test electrode, and the electrochemical intercalation of lithium ions into the artificial graphite powder was tested in each of the prepared electrolytes. Insertion conditions are set at 20°C, 0.03mA / cm 2 and 60mAh / g. After lithium ions are inserted into the artificial graphite powder, at 0.03mA / cm 2 The current flowed through the anode current, and the deintercalation of lithium ions from the artificial graphite powder was tested. The fi...

Embodiment 3

[0060] The evaluation was carried out for quaternary ammonium salts in which the quaternary ammonium cation was fixed as TMEA ion and as anion, respectively, with PF 6 -, BF 4 - , ClO 4 - , TFSI ion, BETI ion, MBSI ion, CHSI ion, BOB ion, CF 3 BF 3 - 、C 2 f 5 BF 3 - 、C 3 f 7 BF 3 - , (C 2 f 5 ) 3 PF 3 - . In addition, LiTFSI was used as a lithium salt.

[0061] Each electrolyte solution was prepared by mixing lithium salt, EC, and each quaternary ammonium salt at a molar ratio of 1 / 4 / 0.1.

[0062] In the same manner as in Example 1, a negative electrode plate having artificial graphite powder was used as a test electrode, and electrochemical intercalation of lithium ions into the artificial graphite powder was tested in each electrolyte solution. Insertion conditions are set at 20°C, 0.03mA / cm 2 and 60mAh / g. After lithium ions are inserted into the artificial graphite powder, at 0.03mA / cm 2 The current flowed through the anode current, and the deinterc...

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Abstract

A nonaqueous electrolyte solution for electrochemical energy-storing device, comprising (a) a lithium salt, (b) a quaternary ammonium salt containing a quaternary ammonium cation having three or more methyl groups, and (c) a nonaqueous solvent, that allows reliable insertion and extraction of lithium ions into and out of a negative-electrode material having a graphite structure even when the quaternary ammonium salt is dissolved in the nonaqueous electrolyte solution, provides an electrochemical energy-storing device that allows a higher voltage setting in charge and is resistant to capacity deterioration even after repeated charge / discharge cycles.

Description

technical field [0001] The present invention relates to electrochemical energy storage devices such as electric double-layer capacitors and non-aqueous electrolyte secondary batteries, and particularly relates to improving the characteristics of electrode reactions by improving the non-aqueous electrolyte. Background technique [0002] Polarized electrodes are used in electric double layer capacitors with positive and negative electrodes. During charge and discharge, since cations and anions are adsorbed and desorbed on the electrode surface, they can be charged and discharged under high load. The polarized electrode uses activated carbon powder or fiber having a high specific surface area, and the electrode is produced by kneading and molding activated carbon, carbon black as a conductive agent, and a binder added as needed. In such an electric double layer capacitor, when the cations are ammonium cations, the cations are ions that are difficult to solvate and move easily, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01G9/038H01G11/62H01M10/052H01M10/0568H01M10/36
CPCY02E60/122H01G9/155Y02E60/13H01G9/035H01M10/0568H01G9/038H01M10/052H01G11/62H01G11/60Y02E60/10H01G11/58
Inventor 松井彻出口正树芳泽浩司
Owner PANASONIC CORP
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