Lithium secondary battery electrolyte with low internal resistance and lithium secondary battery

A lithium secondary battery and electrolyte technology, applied in secondary batteries, secondary battery repair/maintenance, non-aqueous electrolyte storage batteries, etc., can solve the problem of unstable battery cycle, affecting the overall performance of the battery, and complex SEI film composition and morphology and other problems, to achieve the effect of reducing internal resistance and good low temperature performance

Inactive Publication Date: 2020-03-24
GUANGZHOU TINCI MATERIALS TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] It can be seen that, in containing LiPF 6 In the electrolyte solution of lithium salt, due to containing LiPF 6 The electrolyte solution is prone to inevitable thermal decomposition at high temperature, resulting in the formation of HF. At the same time, various volatile and potentially toxic organic phosphate compounds will directly affect the overall performance of the battery, and the existing methods fo

Method used

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  • Lithium secondary battery electrolyte with low internal resistance and lithium secondary battery
  • Lithium secondary battery electrolyte with low internal resistance and lithium secondary battery
  • Lithium secondary battery electrolyte with low internal resistance and lithium secondary battery

Examples

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Example Embodiment

[0029] Example 1

[0030] (1) Preparation of positive electrode sheet for lithium secondary battery

[0031] The positive active material lithium nickel cobalt manganese (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 ), conductive agent Super-P, adhesive PVDF according to the mass ratio 96:2.0:2.0 dissolved in the solvent N-methylpyrrolidone and mixed uniformly to make a positive electrode slurry, and then uniformly coat the positive electrode slurry on the current collector aluminum foil , The coating amount is 0.018g / cm 2 After drying at 85°C, cold pressing, trimming, cutting, and slitting are performed, and then dried at 85°C for 4 hours under vacuum conditions, and the tabs are welded to make the positive electrode sheet of the lithium secondary battery that meets the requirements.

[0032] (2) Preparation of negative electrode sheet for lithium secondary battery

[0033] The negative electrode active material graphite, conductive agent Super-P, thickener CMC, and binder SBR are dissolved in the sol...

Example Embodiment

[0038] Example 2

[0039] The lithium secondary battery was prepared according to the method of Example 1. The difference is that the electrolyte of the lithium secondary battery uses 10.0% of the total mass of the electrolyte as the lithium salt, and the non-aqueous organic solvent is ethylene carbonate and ethyl methyl carbonate. It accounts for 85.5% of the total mass of the electrolyte, and the mass ratio is 1:2. Add sodium tetrafluorophosphate, which accounts for 0.5% of the total mass of the electrolyte. The second additives are fluoroethylene carbonate and lithium difluorophosphate, which respectively account for 3.0% and 1.0% of the total mass of the electrolyte. The cathode material used in lithium secondary batteries is LiNi 0.8 Co 0.1 Mn 0.1 O 2 .

Example Embodiment

[0040] Example 3

[0041] The lithium secondary battery was prepared according to the method of Example 1. The difference is that the electrolyte of the lithium secondary battery uses 13.0% of the total mass of the electrolyte as the lithium salt, and the non-aqueous organic solvent is ethylene carbonate and ethyl methyl carbonate. It accounts for 85.0% of the total mass of the electrolyte, and the mass ratio is 1:3. Potassium tetrafluorophosphate is added to account for 0.5% of the total mass of the electrolyte. The second additive is fluoroethylene carbonate, which accounts for 1.5% of the total mass of the electrolyte. The cathode material used in lithium secondary batteries is LiNi 0.8 Co 0.15 Al 0.05 O 2 .

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Abstract

The invention provides a lithium secondary battery electrolyte. The preparation method comprises the following steps: adding polyfluorophosphate with a specific structure and a non-aqueous solvent into LiPF6 electrolyte lithium salt, and performing reasonable mixing to obtain the electrolyte. The lithium secondary battery using the electrolyte can have good thermal stability and chemical stabilityin the high-rate charging and discharging process, and meanwhile, has low internal resistance, good low-temperature performance and long cycle life.

Description

technical field [0001] The invention relates to the field of lithium secondary battery electrolyte, in particular to an electrolyte containing a specific fluorophosphate additive. Background technique [0002] Electrolyte is the medium that realizes the migration of lithium ions between positive and negative electrodes in lithium secondary batteries, and has an important impact on lithium battery capacity, operating temperature, cycle efficiency and safety. Generally, it is prepared from raw materials such as high-purity organic solvents, electrolyte lithium salts, and main additives under certain conditions. In order to improve the various performances of lithium batteries, the improvement of the electrolyte is a current research hotspot. [0003] As a lithium salt in the electrolyte, the basic requirements that must be met are: high purity, low molecular weight, low toxicity, complete dissolution and dissociation in non-aqueous solvents, good thermal stability, strong che...

Claims

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Application Information

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IPC IPC(8): H01M10/0567H01M10/0525H01M10/058H01M10/42
CPCH01M10/0525H01M10/0567H01M10/058H01M10/4235Y02E60/10Y02P70/50
Inventor 范伟贞刘念滔范超君赵经纬
Owner GUANGZHOU TINCI MATERIALS TECH
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