Lithium secondary cell electrolyte

A lithium secondary battery and electrolyte technology, applied in secondary batteries, circuits, electrical components, etc., can solve the problems of decreased discharge capacity, interference with electrochemical reactions, and impact on battery electrode cycle life and charge-discharge efficiency

Inactive Publication Date: 2002-03-13
TIANJIN CHEM RES & DESIGN INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The decomposition products interfere with the electrochemical reaction and reduce the discharge c...

Method used

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  • Lithium secondary cell electrolyte
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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Prepare 1 mole lithium hexafluorophosphate electrolyte of EC / DEC, EC / DMC, EC / DEC / DMC, EC / EMC, EC / DMC / EMC, PC / DEC / DMC and other systems in a dry box with a moisture content of less than 20ppm. The electrolyte is injected into a lithium secondary battery with a positive electrode lithium cobalt compound and a negative electrode carbon. The battery is charged with a constant current (1CA) at room temperature (20°C) until it reaches 4.2V, and then continues to charge at a constant voltage of 4.2V. 4 hours. This was followed by discharge at a constant current (1CA). Continue to discharge until the final voltage is 2.7V. The charging and discharging cycle was repeated 300 times, and the charging and discharging capacity, efficiency and cycle life were measured.

[0035] The evaluation results of the battery are shown in Table 2

[0036]

[0037] After 300 charge-discharge cycles, the discharge capacity is more than 84.5% of the initial discharge capacity.

Embodiment 2

[0039] In a dry box with a water content of less than 20ppm, prepare 1 mole lithium hexafluorophosphate electrolytes of EC / DEC, EC / DMC, EC / DEC / DMC, EC / EMC, EC / DMC / EMC, PC / DEC / DMC and other systems, respectively Add 0.01-10% sulfur-containing compound, and inject each electrolyte solution into a lithium secondary battery with a positive electrode lithium cobalt compound and a negative electrode carbon, and charge the battery with a constant current (1CA) at room temperature (20°C) until it reaches 4.2 V, and then continue to charge for 4 hours at a constant voltage of 4.2V. This was followed by discharge at a constant current (1CA). Continue to discharge until the final voltage is 2.7V. The charging and discharging cycle was repeated 300 times, and the charging and discharging capacity, efficiency and cycle life were measured.

[0040] The evaluation results of the battery are shown in Table 3

[0041]

[0042] After 300 charge-discharge cycles, the discharge capac...

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Abstract

The present invention belongs to the field of lithium iron cell producing technology and the nonaqueous electrolyte liquid consists of organic carbonate as solvent in 85-90 wt% and electrolyte salt in 10-15 wt%, the solvent consists of one of vinyl carbonate and alloy carbonate and one or more of dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; and the electrolyte salt is one of LiPF6, LiAsF6, LiClO4 and LiBF4. Into the electrolyte liquid, sulfur containing compound in 0.01-10 wt% may be also added to raise the charge and discharge efficienty and circulation life of the cell.The electrolyte liquid of the present invention is well compatible with positive and negative electrode material in secondary lithium ion cell.

Description

[0001] The invention relates to the technical field of lithium ion battery manufacturing, in particular to a nonaqueous electrolytic solution for lithium secondary batteries. Background technique [0002] At present, due to the high working voltage (3.6V), small size, light weight, no memory effect, no pollution, small self-discharge, and long cycle life, lithium secondary batteries are widely used in mobile phones, cameras, notebook computers, and portable appliances. . The battery includes a positive pole, an electrolyte, and a negative pole. The positive pole is lithium cobaltate, or lithium manganese oxide or lithium nickelate, the electrolyte is lithium hexafluorophosphate dissolved in a carbonate solvent, and the negative pole is carbon material or metal lithium. [0003] The current commonly used electrolyte preparation is more concerned with the conductivity of the electrolyte system, and the compatibility of the positive and negative electrode mater...

Claims

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Application Information

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IPC IPC(8): H01B1/12H01M10/0567
CPCY02E60/122Y02E60/10
Inventor 孙新华欧秀芹
Owner TIANJIN CHEM RES & DESIGN INST
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