阅读说明：本技术 可耐高压和大电流循环的自支撑无机-有机复合电解质及制备方法 (Self-supporting inorganic-organic composite electrolyte capable of resisting high voltage and large current circulation and preparation method thereof ) 是由 纪伟伟 蔡超 高鹏 刘兴江 于 2020-05-22 设计创作，主要内容包括：本发明属于化学电源中的固态电池技术领域,特别是涉及一种可耐高压和大电流循环的自支撑无机-有机复合电解质及制备方法。该电解质由以下原料组成：1-2质量份有机聚合物、1-2质量份锂盐、2-6质量份无机陶瓷粉末以及适量溶剂；无机陶瓷为主体,聚合物和锂盐为填料；有机聚合物为聚偏氟乙烯、聚偏氟乙烯-六氟丙烯共聚物、橡胶类、聚氨酯中的一种或多种；溶剂为DMF溶剂或DMAC溶剂；锂盐为LiFSI或LiTFSI；无机陶瓷为氧化物陶瓷LZTO、LLZO、LLZTO、LLZNO、LAGP或者硫化物陶瓷LAPS中的一种或多种组合；该电解质在常温下能够耐4.4V电压,且在2mA/cm<Sup>2</Sup>的大电流密度下能够正常充放电。(The invention belongs to the technical field of solid-state batteries in chemical power supplies, and particularly relates to a self-supporting inorganic-organic composite electrolyte capable of resisting high voltage and large current circulation and a preparation method thereof. The electrolyte consists of the following raw materials: 1-2 parts by mass of organic polymer, 1-2 parts by mass of lithium salt, 2-6 parts by mass of inorganic ceramic powder and a proper amount of solvent; inorganic ceramic is used as a main body, and polymer and lithium salt are used as fillers; the organic polymer is one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, rubber and polyurethane; the solvent is DMF solvent or DMAC solvent; the lithium salt is LiFSI or LiTFSI; the inorganic ceramic is one or more of oxide ceramic LZTO, LLZO, LLZTO, LLZNO, LAGP or sulfide ceramic LAPS; the electrolyte can resist 4.4V voltage at normal temperature2mA/cm 2 Can be normally charged and discharged under high current density.)

1. A self-supporting inorganic-organic composite electrolyte capable of resisting high voltage and large current circulation is characterized in that: the electrolyte consists of the following raw materials: 1-2 parts by mass of organic polymer, 1-2 parts by mass of lithium salt, 2-6 parts by mass of inorganic ceramic powder and a proper amount of solvent; the inorganic ceramic is used as a main body, and the polymer and the lithium salt are used as fillers;

wherein the organic polymer is one or a combination of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, rubber and polyurethane;

the lithium salt is LiFSI or LiTFSI;

the inorganic ceramic is one or more of oxide ceramic LZTO, LLZO, LLZTO, LLZNO, LAGP or sulfide ceramic LAPS;

the solvent is DMF solvent or DMAC solvent;

the electrolyte can resist 4.4V voltage at normal temperature and can resist 2mA/cm²High current density ofCan be normally charged and discharged at a certain temperature.

2. The self-supporting inorganic-organic composite electrolyte of claim 1, wherein: the electrolyte has conductivity of 7 × 10^-4S/cm。

3. The self-supporting inorganic-organic composite electrolyte of claim 1, wherein: the electrolyte is circulated at normal temperature and 0.2C multiplying power, and the capacity retention rate can reach 94.1% after 200 cycles.

4. A method for preparing the electrolyte according to any one of claims 1 to 3, characterized in that the method comprises the steps of:

s1, stirring or ball-milling 1-2 parts by mass of polymer in a proper amount of solvent for 1-4 hours to form a uniform solution;

s2, adding 1-2 parts by mass of lithium salt into the uniform solution, and stirring or ball-milling for 0.5-6 h;

s3, adding 2-6 parts by mass of inorganic ceramic powder, and stirring or ball-milling for 6-12 hours to form a uniform colloidal solution with high viscosity;

s4, pouring the colloidal solution into a polytetrafluoroethylene membrane by a solution pouring method, drying at room temperature of 60-120 ℃ for 6-16h, vacuum drying at 60-120 ℃ for 12-36h, and removing residual solvent to obtain the self-supporting composite solid electrolyte membrane with the thickness of 20-400 um.

Technical Field

The invention belongs to the technical field of solid-state batteries in chemical power supplies, and particularly relates to a self-supporting inorganic-organic composite electrolyte capable of resisting high voltage and large current circulation and a preparation method thereof.

Background

The conventional lithium ion battery widely applied at present mainly adopts organic electrolyte, so that a great amount of heat generated in other abnormal working states such as overcharge, internal short circuit and the like can cause the electrolyte to be rapidly vaporized, further battery explosion and ignition combustion can be caused, and the fundamental solution of the potential safety hazards is to develop a solid-state energy storage device, namely, a non-volatile solid electrolyte is used for replacing the organic electrolyte to develop a solid-state lithium battery technology based on a high-safety solid electrolyte system.

The solid-state battery has high safety and high specific energy, is expected to break through the bottleneck problems of the current restriction on the safety, the driving range and the like of the electric automobile, and will start the super cycle of the new energy automobile industry, so that countries in Europe, America, Japan, Korea and the like all list the research and development of the solid-state secondary battery as the key strategic development direction of the next 10 years, and the solid-state battery is considered to be a substitute and a promising candidate for the next generation of clean energy storage. It is particularly noted that, after 2010, attention to solid electrolytes used in solid batteries has been exponentially increased, and inorganic solid electrolytes have advantages of nonflammability, nonvolatility, no liquid leakage, wide battery voltage window, high energy density, and the like, as compared with organic liquid electrolytes.

At present, the solid electrolyte mainly researched by scientific research institutions and colleges can only circulate under a small current, and the adopted electrolyte system is generally a high lithium salt system, so that high conductivity is obtained, and the prepared electrolyte cannot be operated at a large current at normal temperature, so that the application development of the solid battery cannot be met.

Disclosure of Invention

Aiming at the problems of the solid electrolyte in the prior art, the invention aims to provide a self-supporting inorganic-organic composite electrolyte capable of resisting high voltage and large current circulation and a preparation method thereof by complexing high-content ceramic and low lithium salt, wherein the electrolyte has abundant 3D network space and can be charged and discharged at large current, so that the large current charging and discharging capacity and the circulation stability of a battery are improved.

In order to achieve the purpose, the invention adopts the following specific technical scheme:

a self-supporting inorganic-organic composite electrolyte capable of resisting high voltage and large current circulation, which consists of the following raw materials: 1-2 parts by mass of organic polymer, 1-2 parts by mass of lithium salt, 2-6 parts by mass of inorganic ceramic powder and a proper amount of solvent; the inorganic ceramic is used as a main body, and the polymer and the lithium salt are used as fillers;

wherein the organic polymer is one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, rubber and polyurethane;

the lithium salt is LiFSI or LiTFSI;

the inorganic ceramic is one or more of oxide ceramic LZTO, LLZO, LLZTO, LLZNO, LAGP or sulfide ceramic LAPS;

the solvent is DMF solvent or DMAC solvent;

the electrolyte can resist 4.4V voltage at normal temperature and can resist 2mA/cm²Can be normally charged and discharged under high current density.

Further, the electrolyte can have an electrical conductivity of up to 7 x 10^-4S/cm。

Furthermore, the electrolyte is circulated at normal temperature and 0.2C multiplying power, and the capacity retention rate of 200 cycles of circulation can reach 94.1%.

Furthermore, the invention also discloses a preparation method of the electrolyte, which mainly comprises the following steps:

s1, stirring or ball-milling 1-2 parts by mass of polymer in a proper amount of solvent for 1-4 hours to form a uniform solution;

s2, adding 1-2 parts by mass of lithium salt into the uniform solution, and stirring or ball-milling for 0.5-6 h;

s3, adding 2-6 parts by mass of inorganic ceramic powder, and stirring or ball-milling for 6-12 hours to form a uniform colloidal solution with high viscosity;

s4, pouring the colloidal solution into a polytetrafluoroethylene membrane by a solution pouring method, drying at room temperature of 60-120 ℃ for 6-16h, vacuum drying at 60-120 ℃ for 12-36h, and removing residual solvent to obtain the self-supporting composite solid electrolyte membrane with the thickness of 20-400 um.

The invention has the advantages and positive effects that:

the self-supporting inorganic-organic composite electrolyte capable of resisting high voltage and large current circulation, provided by the invention, takes the inorganic ceramic as a main body, and the organic polymer and the lithium salt are used as fillers to modify the high interface of the inorganic ceramic, so that good interface contact and abundant 3D network space are formed among ceramic particles, the transmission of lithium ions is accelerated, the internal short circuit condition of a battery is reduced, and the electrochemical performance of the battery is improved.

Drawings

FIG. 1 is a surface topography of an inorganic-organic composite electrolyte in example 1 of the present invention;

FIG. 2 is a graph showing electrochemical impedance of an inorganic-organic composite electrolyte according to example 1 of the present invention;

FIG. 3 is a graph showing that the small current density at room temperature is 0.04mA/cm in example 1 of the present invention²And a high current density of 2mA/cm²The discharge capacity curve of (1);

FIG. 4 is a graph of the cycle performance at room temperature of 0.2C in example 1 of the present invention.

Detailed Description

The invention discloses a self-supporting inorganic-organic composite electrolyte capable of resisting high voltage and large current circulation, which consists of the following raw materials in percentage by mass: 1-2 parts by mass of organic polymer, 1-2 parts by mass of lithium salt, 2-6 parts by mass of inorganic ceramic powder and a proper amount of solvent; the inorganic ceramic is used as a main body, and the polymer and the lithium salt are used as fillers.

Wherein the organic polymer is one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, rubber and polyurethane;

the solvent is DMF solvent or DMAC solvent;

the lithium salt is LiFSI or LiTFSI;

the inorganic ceramic is one or more of oxide ceramic LZTO, LLZO, LLZTO, LLZNO, LAGP or sulfide ceramic LAPS;

the invention discloses a preparation method of the self-supporting inorganic-organic composite electrolyte, which mainly comprises the following steps:

s1, stirring or ball-milling 1-2 parts by mass of polymer in a proper amount of solvent for 1-4 hours to form a uniform solution;

s2, adding 1-2 parts by mass of lithium salt into the uniform solution, and stirring or ball-milling for 0.5-6 h;

s3, adding 2-6 parts by mass of inorganic ceramic powder, and stirring or ball-milling for 6-12 hours to form a uniform colloidal solution with high viscosity;

s4, pouring the colloidal solution into a polytetrafluoroethylene membrane by a solution pouring method, drying at room temperature of 60-120 ℃ for 6-16h, vacuum drying at 60-120 ℃ for 12-36h, and removing residual solvent to obtain the self-supporting composite solid electrolyte membrane with the thickness of 20-400 um.

For a further understanding of the contents, features and effects of the present invention, the following examples are illustrated in the accompanying drawings and described in the following detailed description: