Flame-retardant electrolyte and lithium secondary battery thereof

A lithium secondary battery and electrolyte technology, applied in secondary batteries, non-aqueous electrolyte storage batteries, lithium storage batteries, etc., can solve the problems of high cost, affecting battery power performance and cycle performance, complex process, etc., and achieve plasticity and Improved flexibility, improved electrochemical performance, and improved wettability

Inactive Publication Date: 2019-03-01
福建冠城瑞闽新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

MasayukiMorita et al. improved the flame retardancy of the electrolyte by adding trimethyl phosphate (TMP), but it would affect the cycle life of the battery; The problem of cycle performance; some

Method used

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  • Flame-retardant electrolyte and lithium secondary battery thereof
  • Flame-retardant electrolyte and lithium secondary battery thereof
  • Flame-retardant electrolyte and lithium secondary battery thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] The non-aqueous solvents ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) according to the mass ratio in Table 1 (40: 10:25:20:5) to mix evenly, put the solvent into the refrigerator attached to the glove box, and place it at zero temperature for 12 hours. LiFSI (lithium bisfluorosulfonyl imide) 0.25mol / L) was added while stirring, and the monitored temperature should not exceed 40 degrees. After cooling to room temperature, add the film-forming agent (vinylene carbonate (VC) 2.0wt.%+1,3-propane sultone (1,3-PS) 1.5wt.%) and flame retardant (2-ethylhexyl diphenyl phosphate tripolyphosphazene (DPOF) 10.0wt .% + tris(2,2,2-trifluoroethyl) phosphite (TTFP) 5.0wt.% + dimethyl methylphosphonate (DMMP) 10.0wt.%), mix well to obtain electrolyte.

Embodiment 2

[0051] The non-aqueous solvents ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) according to the mass ratio in Table 1 (40: 10:25:20:5) to mix evenly, put the solvent into the refrigerator attached to the glove box, and place it at zero temperature for 12 hours. LiFSI (lithium bisfluorosulfonyl imide) 0.15mol / L) was added while stirring, and the monitored temperature should not exceed 40 degrees. After cooling to room temperature, add the film-forming agent (vinylene carbonate (VC) 2.0wt.%+1,3-propane sultone (1,3-PS) 1.5wt.%+fluoroethylene carbonate (FEC) 1.0wt.%) and flame retardant (2-ethylhexyl di Phenyl phosphate tripolyphosphazene (DPOF) 5.0wt.% + tris(2,2,2-trifluoroethyl) phosphite (TTFP) 10.0wt.% + dimethyl methylphosphonate (DMMP) 10.0wt.%), mixed evenly to obtain electrolyte.

Embodiment 3

[0053] The non-aqueous solvents ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) according to the mass ratio in Table 1 (40: 10:25:20:5) to mix evenly, put the solvent into the refrigerator attached to the glove box, and place it at zero temperature for 12 hours. LiFSI (lithium bisfluorosulfonyl imide) 0.05mol / L) was added while stirring, and the monitored temperature should not exceed 40 degrees. After cooling to room temperature, add the film-forming agent (vinylene carbonate (VC) 2.0wt.%+1,3-propane sultone (1,3-PS) 1.5wt.%+ethylene sulfate (DTD) 1.0wt.%) and flame retardant (2-ethylhexyldiphenyl Phosphate-based tripolyphosphazene (DPOF) 10.0wt.% + Tris(2,2,2-trifluoroethyl) phosphite (TTFP) 5.0wt.% + Dimethyl methylphosphonate (DMMP) 10.0 wt.%), mixed evenly to obtain the electrolyte.

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Abstract

The invention discloses a flame-retardant electrolyte and a lithium secondary battery thereof. The flame-retardant electrolyte comprises electrolyte lithium salt, an organic solvent, a small amount ofa universal film forming additive and a flame-retardant additive. The flame-retardant additive mainly comprises a mixture of diphenyl phosphate and derivatives of diphenyl phosphate, trifluoroethyl phosphate and derivatives of trifluoroethyl phosphate, and dimethyl methylphosphonate and derivatives of dimethyl methylphosphonate. According to the invention, performance indexes of the processed electrolyte such as viscosity, ionic conductivity, wettability, pole pieces and diaphragm flexibility are basically unchanged when being compared with the conventional electrolyte, even improved, and a PVDF coating is arranged and then partially dissolved. The lithium-ion batteries prepared by different proportions of the flame-retardant additives not only have excellent safety performances similar to polymer electrolytes, but also have certain improvement effects on battery consistency and electrochemical performances.

Description

technical field [0001] The invention relates to the technical field of lithium battery electrolyte, in particular to a flame-retardant electrolyte and a lithium secondary battery thereof. Background technique [0002] Compared with traditional secondary batteries, lithium-ion batteries have the advantages of light weight, high specific energy and long cycle life. Lithium-ion batteries have been introduced into the field of electric vehicles in recent years, but one of the factors hindering its rapid promotion is safety issues. The traditional non-aqueous electrolyte is composed of lithium hexafluorophosphate (LiPF6), carbonate solvent and general additives, which has the disadvantage of being flammable. Once an internal short circuit occurs in the lithium-ion battery, the internal pressure of the gas produced in the battery will gradually increase, resulting in an explosion or fire accident. [0003] Adding flame retardant additives to electrolytes is one of the most econo...

Claims

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Application Information

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IPC IPC(8): H01M10/0567H01M10/052
CPCH01M10/052H01M10/0567Y02E60/10
Inventor 陈曦王浩然罗茂发杨允杰赵家兴
Owner 福建冠城瑞闽新能源科技有限公司
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