WO2022021781A1 - 阻燃液态电解质、锂电池及其制备方法 - Google Patents

阻燃液态电解质、锂电池及其制备方法 Download PDF

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WO2022021781A1
WO2022021781A1 PCT/CN2020/139760 CN2020139760W WO2022021781A1 WO 2022021781 A1 WO2022021781 A1 WO 2022021781A1 CN 2020139760 W CN2020139760 W CN 2020139760W WO 2022021781 A1 WO2022021781 A1 WO 2022021781A1
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electrolyte
lithium
liquid electrolyte
retardant liquid
flame retardant
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PCT/CN2020/139760
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English (en)
French (fr)
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李�诚
陆子恒
刘国华
杨春雷
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深圳先进技术研究院
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Publication of WO2022021781A1 publication Critical patent/WO2022021781A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention relates to the technical field of battery preparation, in particular to a flame retardant liquid electrolyte, a lithium battery and a preparation method thereof.
  • Lithium batteries have a wide operating temperature, high mass specific energy and volume specific energy, and have been widely used in automotive electronics, mobile digital products and other fields.
  • the energy storage effect of existing lithium batteries can no longer meet people's needs, and higher energy density is the main direction people pursue, which requires lithium-ion batteries with high-capacity electrodes and stable electrolytes.
  • traditional organic lipid electrolytes are easy to burn, and there are great safety hazards.
  • flame retardant electrolytes including liquid flame retardant electrolytes and solid flame retardant electrolytes
  • solid electrolytes seriously affect its practical application due to large interface problems.
  • Liquid electrolytes are still the mainstream of the market due to their good wettability, low interface impedance, and simple preparation. Therefore, the strategy of flame retardant liquid electrolytes is proposed.
  • a preparation method of a flame retardant liquid electrolyte comprising the following steps:
  • the base electrolyte is formed by mixing the lithium salt with the phosphate solvent
  • the base electrolyte and the first solution are mixed to form the flame retardant liquid electrolyte.
  • the lithium salt is selected from lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium bistrifluoromethanesulfonimide, lithium bisoxalatoborate, lithium oxalate difluoroborate, lithium At least one of lithium chlorate and lithium tetrafluoroborate.
  • the molar fraction of the lithium salt is 3 mol/L ⁇ 7 mol/L.
  • the phosphate ester solvent is selected from one or both of trimethyl phosphate and triethyl phosphate.
  • the negative electrode protective agent is one or both of fluoroethylene carbonate and ethylene ethylene carbonate.
  • the commercial electrolyte includes lithium hexafluorophosphate as a solute and at least one of ethylene carbonate, diethyl carbonate or dimethyl carbonate as a solvent.
  • the volume percentage of the base electrolyte is 35%-45%
  • the volume percentage of the commercial electrolyte is 40%-60%
  • the negative electrode protective agent has a volume percentage of 35%-45%.
  • the volume percentage is 5% to 20%.
  • the present invention also provides a flame-retardant liquid electrolyte, which is prepared by the preparation method of the flame-retardant liquid electrolyte.
  • the present invention also provides a method for preparing a lithium battery, comprising the following steps: attaching a positive electrode material and a negative electrode material on both sides of the flame retardant liquid electrolyte, and heating and polymerizing to obtain the lithium battery.
  • the present invention also provides a lithium battery, comprising the flame retardant liquid electrolyte and a positive electrode material and a negative electrode material attached to both sides of the flame retardant liquid electrolyte.
  • the above flame retardant liquid electrolyte is formed by mixing a lithium salt and a phosphate solvent to form a basic electrolyte, a negative electrode protective agent is mixed with a commercial electrolyte to form a first solution, and the basic electrolyte and the first solution are mixed to form the resistance.
  • the flame retardant liquid electrolyte can effectively improve the flame retardancy of the electrolyte, and at the same time, the coulombic efficiency is high, the preparation process is simple, the raw material sources are wide, the cost is low, and it is suitable for industrial production.
  • the above flame retardant liquid electrolyte can be used for the preparation of lithium ion batteries, which can effectively improve the flame retardancy of the electrolyte and improve the safety of the battery, and the added negative electrode protective agent reacts with the negative electrode to form an artificial SEI protective layer before cycling. During the cycling process, the formation of lithium dendrites can be effectively suppressed and the cycling stability of the lithium battery can be improved.
  • FIG. 1 is a flow chart of the steps of a flame retardant liquid electrolyte according to an embodiment
  • FIG. 2 is a schematic structural diagram of a lithium battery provided by an embodiment
  • Fig. 3 is the test curve diagram of the charge-discharge cycle of the flame-retardant liquid electrolyte battery sample provided in Example 1 of the present invention at a rate of 0.5C;
  • FIG. 4 is a test curve diagram of the charge-discharge cycle of the flame-retardant liquid electrolyte battery sample provided in Example 3 of the present invention at a rate of 0.5C.
  • first and second are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as “first” or “second” may expressly or implicitly include one or more of that feature.
  • “plurality” means two or more, unless otherwise expressly and specifically defined.
  • the preparation method for the flame retardant liquid electrolyte includes the following steps:
  • a base electrolyte is formed by mixing a lithium salt with a phosphate ester solvent.
  • the lithium salt is selected from lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium bistrifluoromethanesulfonimide, lithium bisoxalatoborate, lithium oxalate difluoroborate, lithium At least one of lithium chlorate and lithium tetrafluoroborate.
  • lithium salts have a great impact on the energy density, power density, wide electrochemical window, cycle life, safety performance, etc. of lithium batteries.
  • the energy density and power of lithium batteries can be improved. Density, wide electrochemical window, cycle life and safety performance.
  • the molar fraction of the lithium salt is 3 mol/L ⁇ 7 mol/L.
  • the phosphate ester solvent is selected from one or both of trimethyl phosphate and triethyl phosphate.
  • S120 A first solution is formed after mixing the negative electrode protective agent and the commercial electrolyte.
  • the negative electrode protective agent is one or both of fluoroethylene carbonate and ethylene ethylene carbonate.
  • the negative protective agent added in the above-mentioned embodiment of the present invention reacts with the negative electrode of the lithium ion battery prepared subsequently to form an artificial SEI protective layer before the cycle, which can effectively suppress the formation of lithium dendrites and improve the performance of the lithium battery during the long cycle. Cyclic stability.
  • the commercial electrolyte comprises lithium hexafluorophosphate (LiPF 6 ) as a solute, and at least one of ethylene carbonate (EC), diethyl carbonate (DEC) or dimethyl carbonate (DMC) as a solute. solvent.
  • LiPF 6 lithium hexafluorophosphate
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • DMC dimethyl carbonate
  • the commercial electrolyte is 1 mole of LiPF6 dissolved in a solvent of EC:DMC:DEC in a volume ratio of 1:1:1.
  • Step S130 Mixing the base electrolyte and the first solution to form the flame retardant liquid electrolyte.
  • the volume percentage of the basic electrolyte is 35%-45%
  • the volume percentage of the commercial electrolyte is 40%-60%
  • the volume percentage of the negative electrode protective agent is 5%- 20%.
  • the commercial electrolyte contains a large amount of carbonate components, it is a highly flammable substance and has a great potential safety hazard. During the battery cycle process, lithium dendrites easily penetrate the separator, resulting in a short circuit of the battery.
  • the phosphate ester is highly non-flammable, and the negative electrode protective agent can form a good SEI protective layer on the surface of lithium metal to inhibit the formation of lithium dendrites, at this time, by using the above ratio combination, the formed liquid flame retardant electrolyte not only It can inherit the fire extinguishing properties and wide electrochemical window of the phosphate solution electrolyte, and can effectively suppress the formation of lithium dendrites.
  • the above flame retardant liquid electrolyte is formed by mixing a lithium salt and a phosphate solvent to form a basic electrolyte, a negative electrode protective agent is mixed with a commercial electrolyte to form a first solution, and the basic electrolyte and the first solution are mixed to form the resistance.
  • the flame retardant liquid electrolyte can effectively improve the flame retardancy of the electrolyte, and at the same time, the coulombic efficiency is high, the preparation process is simple, the raw material sources are wide, the cost is low, and it is suitable for industrial production.
  • S310 The positive electrode material and the negative electrode material are respectively attached to both sides of the flame retardant liquid electrolyte according to claim 8, and heated and polymerized to obtain the lithium battery.
  • FIG. 2 is a schematic structural diagram of a lithium battery provided in an embodiment, including a flame retardant liquid electrolyte 210 and a positive electrode material 220 and a negative electrode material 230 attached to both sides of the modified solid electrolyte 210 .
  • the positive electrode material 220 and the negative electrode material 230 are the positive electrode material and the negative electrode material commonly used in existing lithium batteries.
  • the above-mentioned lithium battery including the above-mentioned flame retardant liquid electrolyte, can not only improve the safety performance of the lithium battery, but also the added negative electrode protective agent reacts with the negative electrode to form an artificial SEI protective layer before the cycle, which can effectively suppress the lithium branch during the long cycle. Crystal formation and improve the cycling stability of lithium batteries.
  • the flame-retardant liquid electrolyte provided in this example includes the following components by volume: 35% of the base electrolyte, 60% of the commercial electrolyte and 5% of fluoroethylene carbonate, and is uniformly mixed to form the flame-retardant liquid electrolyte.
  • the basic electrolyte is a basic electrolyte formed by dissolving lithium bisfluorosulfonimide in trimethyl phosphate solvent, and in the basic electrolyte, the mole fraction of lithium bisfluorosulfonimide is 5mol/L .
  • step (3) Pipette 0.7 ml of the basic electrolyte and add it to step (2), and stir well at room temperature to form the flame retardant liquid electrolyte.
  • the positive electrode material and the negative electrode material are respectively attached to both sides of the flame retardant liquid electrolyte, and heated and polymerized to obtain the lithium battery.
  • the rags Immerse the rags in the flame-retardant liquid electrolyte of the embodiment of the present invention, wait for it to be completely soaked, and then carry out an ignition test. In the case of burning an open flame for several minutes, the rags are still not burned in the test, which shows that the resistance provided by this example is provided.
  • the flammable liquid electrolyte has good flame retardant properties.
  • the flame-retardant liquid electrolyte provided in this example includes the following components by volume: 45% of the base electrolyte, 40% of the commercial electrolyte and 15% of ethylene ethylene carbonate, and is uniformly mixed to form the flame-retardant liquid electrolyte.
  • the basic electrolyte is a basic electrolyte formed by dissolving lithium bisfluorosulfonimide in trimethyl phosphate solvent, and in the basic electrolyte, the mole fraction of lithium bisfluorosulfonimide is 7mol/L .
  • step (3) Pipette 0.9 ml of the basic electrolyte and add it to step (2), and stir well at room temperature to form the flame retardant liquid electrolyte.
  • the positive electrode material and the negative electrode material are respectively attached to both sides of the flame retardant liquid electrolyte, and heated and polymerized to obtain the lithium battery.
  • the rags Immerse the rags in the flame-retardant liquid electrolyte of the embodiment of the present invention, wait for it to be completely soaked, and then carry out an ignition test. In the case of burning an open flame for several minutes, the rags are still not burned in the test, which shows that the resistance provided by this example is provided.
  • the flammable liquid electrolyte has good flame retardant properties.
  • the flame-retardant liquid electrolyte provided in this example includes the following components by volume: 40% of the base electrolyte, 50% of the commercial electrolyte and 10% of fluoroethylene carbonate, and is uniformly mixed to form the flame-retardant liquid electrolyte.
  • the described base electrolyte is a base electrolyte formed by dissolving lithium hexafluorophosphate in a trimethyl phosphate solvent, and in the described base electrolyte, the mole fraction of lithium hexafluorophosphate is 3 mol/L.
  • step (3) Pipette 0.8 ml of the basic electrolyte and add it to step (2), and stir well at room temperature to form the flame retardant liquid electrolyte.
  • the positive electrode material and the negative electrode material are respectively attached to both sides of the flame retardant liquid electrolyte, and heated and polymerized to obtain the lithium battery.
  • the rags Immerse the rags in the flame-retardant liquid electrolyte of the embodiment of the present invention, wait for it to be completely soaked, and then carry out an ignition test. In the case of burning an open flame for several minutes, the rags are still not burned in the test, which shows that the resistance provided by this example is provided.
  • the flammable liquid electrolyte has good flame retardant properties.
  • the flame-retardant liquid electrolyte provided in this example includes the following components by volume: 35% of the base electrolyte, 45% of the commercial electrolyte and 20% of ethylene ethylene carbonate, and is uniformly mixed to form the flame-retardant liquid electrolyte.
  • the basic electrolyte is a basic electrolyte formed by dissolving lithium bistrifluoromethanesulfonimide in a triethyl phosphate solvent. In the basic electrolyte, the mole fraction of lithium bistrifluoromethanesulfonimide is is 5mol/L.
  • step (3) Pipette 0.7 ml of the basic electrolyte and add it to step (2), and stir well at room temperature to form the flame retardant liquid electrolyte.
  • the positive electrode material and the negative electrode material are respectively attached to both sides of the flame retardant liquid electrolyte, and heated and polymerized to obtain the lithium battery.
  • the flame-retardant liquid electrolyte provided above is assembled in a lithium battery to perform an electrochemical test, and the details are as follows:
  • the specific battery structure adopts a button cell, which includes a positive electrode, a negative electrode, a separator and an electrolyte instructed at the positive electrode and the negative electrode.
  • the negative electrode is a lithium metal electrode or an electrode sheet composed of graphite, graphene and other negative electrode materials coated on the same current collector
  • the positive electrode is an electrode sheet formed by coating an aluminum foil current collector with lithium iron phosphate
  • the separator is polypropylene. separator, and electrochemical tests were performed to obtain the following experimental results.
  • the rags were soaked in the flame-retardant liquid electrolyte of the embodiment of the present invention, and after it was completely soaked, an ignition experiment was carried out. The strips of cloth are still unburned. It shows that the electrolyte provided by the present invention has good flame retardancy.
  • Figure 3 shows the charge-discharge curve of the sample of Example 1 at a rate of 0.5C. It can be seen from Figure 3 that the battery has a capacity of up to 146mAh/g and a coulombic efficiency of 99.3% after 150 cycles at a rate of 0.5C. .
  • Figure 4 shows the charge-discharge curve of the sample of Example 3 at a rate of 0.5C. It can be seen from Figure 4 that the sample of Example 3 has a capacity of up to 124mAh/g after being cycled for 150 times at a rate of 0.5C, and the Coulombic efficiency reached 99.1%.

Abstract

本发明提供了一种阻燃液态电解质，将锂盐及磷酸酯溶剂混合后形成基础电解质，将负极保护剂与商业电解质混合后形成第一溶液，将所述的基础电解质和所述第一溶液混合形成所述阻燃液态电解质，上述阻燃液态电解质可以有效提高电解质的阻燃性，同时库伦效率高，且制备工艺简单，原料来源广泛，成本低，适合工业化生产。上述阻燃液态电解质，可用于锂离子电池制备，可以有效提高电解质的阻燃性，提高电池的安全性，而且所添加的负极保护剂，在循环前与负极反应生成人工SEI保护层，在长循环过程中能够有效抑制锂枝晶生成和提高锂电池的循环稳定性。

Description

阻燃液态电解质、锂电池及其制备方法 技术领域
本发明涉及电池制备技术领域，特别涉及一种阻燃液态电解质、锂电池及其制备方法。
 背景技术
社会的发展和科技的进步使得人们见证了锂离子电池具有广泛的应用市场。锂电池具有工作温度宽广，高的质量比能量和体积比能量已经被广泛用到汽车电子、移动数码产品等领域。但是现有的锂电池储能效果已经不能满足人们的需求，更高能量密度是人们追求的主要方向，而这需要锂离子电池具有高容量的电极和稳定的电解质。但是锂离子电池在应用的过程中，由于锂枝晶的生长，传统的有机脂类电解质易燃烧等问题存在很大的安全隐患。
目前阻燃电解质包括液态阻燃电解质和固态阻燃电解质成为越来越多人研究的热门领域。但是固态电解质由于较大的界面问题严重影响了它的实际应用，液态电解质由于其良好的湿润性，界面阻抗小，制备简单仍是市场的主流，阻燃液态电解质策略因此被提出。
 技术解决方案
鉴于此，有必要提供一种阻燃性好且电池的循环稳定性的阻燃液态电解质及其制备方法。
一种阻燃液态电解质的制备方法，包括下述步骤：
将锂盐与磷酸酯溶剂混合后形成基础电解质；
将负极保护剂与商业电解质混合后形成第一溶液；及
将所述的基础电解质和所述第一溶液混合形成所述阻燃液态电解质。
在其中一些实施例中，所述锂盐选自双(氟磺酰)亚胺锂、六氟磷酸锂、双三氟甲基磺酰亚胺锂、双乙二酸硼酸锂、草酸二氟硼酸锂、高氯酸锂和四氟硼酸锂中的至少一种。
在其中一些实施例中，在所述基础电解质中，所述锂盐的摩尔分数为3mol/L~7mol/L。
在其中一些实施例中，所述磷酸酯溶剂选自磷酸三甲酯和磷酸三乙酯中的一种或两种。
在其中一些实施例中，所述的负极保护剂为氟代碳酸乙烯酯、碳酸乙烯亚乙酯中的一种或两种。
在其中一些实施例中，所述的商业电解质包括以六氟磷酸锂为溶质，以碳酸乙烯酯或碳酸二乙酯或碳酸二甲酯中至少一种为溶剂。
在其中一些实施例中，在所述液态阻燃电解质中，所述基础电解质的体积百分比为35%-45%，所述商业电解质的体积百分比为40%-60% ，所述负极保护剂的体积百分比为为5％～20％。
本发明还提供了一种阻燃液态电解质，由所述的阻燃液态电解质的制备方法制备而成。
本发明还提供了一种锂电池的制备方法，包括下述步骤：将正极材料和负极材料分别贴合在所述的阻燃液态电解质两面，并加热聚合，得到所述锂电池。
本发明还提供了一种锂电池，包括所述的阻燃液态电解质以及贴合在所述阻燃液态电解质两面的正极材料和负极材料。
 有益效果
上述阻燃液态电解质，将锂盐及磷酸酯溶剂混合后形成基础电解质，将负极保护剂与商业电解质混合后形成第一溶液，将所述的基础电解质和所述第一溶液混合形成所述阻燃液态电解质，上述阻燃液态电解质可以有效提高电解质的阻燃性，同时库伦效率高，且制备工艺简单，原料来源广泛，成本低，适合工业化生产。
上述阻燃液态电解质，可用于锂离子电池制备，可以有效提高电解质的阻燃性，提高电池的安全性，而且所添加的负极保护剂，在循环前与负极反应生成人工SEI保护层，在长循环过程中能够有效抑制锂枝晶生成和提高锂电池的循环稳定性。
 附图说明
为了更清楚地说明本发明实施例的技术方案，下面将对本发明实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为一实施方式的阻燃液态电解质的步骤流程图；
图2为一实施方式提供的锂电池的结构示意图；
图3为本发明实施例1提供的阻燃液态电解质电池样品在0.5C倍率下充放电循环测试曲线图；
图4为本发明实施例3提供的阻燃液态电解质电池样品在0.5C倍率下充放电循环测试曲线图。
 本发明的实施方式
下面详细描述本发明的实施例，所述实施例的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施例是示例性的，旨在用于解释本发明，而不能理解为对本发明的限制。
在本发明的描述中，需要理解的是，术语“上”、“下”、“水平”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个该特征。在本发明的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。
如图1所示，一实施方式的阻燃液态电解质的制备方法，该阻燃液态电解质的制备方法包括如下步骤：
S110：将锂盐与磷酸酯溶剂混合后形成基础电解质。
在其中一些实施例中，所述锂盐选自双(氟磺酰)亚胺锂、六氟磷酸锂、双三氟甲基磺酰亚胺锂、双乙二酸硼酸锂、草酸二氟硼酸锂、高氯酸锂和四氟硼酸锂中的至少一种。
可以理解，优质的锂盐对于锂电池的能量密度、功率密度、宽电化学窗口、循环寿命、安全性能等方面都有着较大的影响，通过选用上述锂盐能够提升锂电池的能量密度、功率密度、宽电化学窗口、循环寿命及安全性能。
在其中一些实施例中，在所述基础电解质中，所述锂盐的摩尔分数为3mol/L~7mol/L。
在其中一些实施例中，所述磷酸酯溶剂选自磷酸三甲酯和磷酸三乙酯中的一种或两种。
S120：将负极保护剂与商业电解质混合后形成第一溶液。
在其中一些实施例中，所述的负极保护剂为氟代碳酸乙烯酯、碳酸乙烯亚乙酯中的一种或两种。
可以理解，本发明上述实施例所添加的负极保护剂，在循环前与后续制备的锂离子电池负极反应生成人工SEI保护层,在长循环过程中能够有效抑制锂枝晶生成和提高锂电池的循环稳定性。
在其中一些实施例中，所述的商业电解质包括以六氟磷酸锂（LiPF 6）为溶质，以碳酸乙烯酯（EC）或碳酸二乙酯（DEC）或碳酸二甲酯（DMC）中至少一种为溶剂。
具体地，所述的商业电解质为1摩尔的LiPF 6溶解于体积比为1：1：1 的EC：DMC：DEC的溶剂中。
步骤S130：将所述的基础电解质和所述第一溶液混合形成所述阻燃液态电解质。
在所述液态阻燃电解质中，所述基础电解质的体积百分比为35%-45%，所述商业电解质的体积百分比为40%-60% ，所述负极保护剂的体积百分比为为5％～20％。
可以理解，由于商业电解质中含有大量的碳酸酯成分，是高度易燃物质，具有很大的安全隐患，电池循环过程中锂枝晶容易穿透隔膜，造成电池短路，而所述基础电解质中，由于磷酸酯具有高度不可燃性，且负极保护剂能在锂金属表面形成很好的SEI保护层，抑制锂枝晶的生成，此时，通过采用上述配比组合，形成的液态阻燃电解质既能继承磷酸酯溶液电解质的灭火特性和宽的电化学窗口，而且能够有效地抑制锂枝晶的形成。
上述阻燃液态电解质，将锂盐及磷酸酯溶剂混合后形成基础电解质，将负极保护剂与商业电解质混合后形成第一溶液，将所述的基础电解质和所述第一溶液混合形成所述阻燃液态电解质，上述阻燃液态电解质可以有效提高电解质的阻燃性，同时库伦效率高，且制备工艺简单，原料来源广泛，成本低，适合工业化生产。
一实施方式提供的一种锂电池的制备方法，包括下述步骤：
S310：将正极材料和负极材料分别贴合在权利要求8所述的阻燃液态电解质两面，并加热聚合，得到所述锂电池。
请参阅图2，为一实施方式提供的锂电池的结构示意图，包括阻燃液态电解质210以及贴合在所述改性固态电解质210两面的正极材料220和负极材料230。
其中，正极材料220和负极材料230为现有锂电池中常用的正极材料和负极材料。
上述锂电池，包括上述阻燃液态电解质，不仅可以提升锂电池的安全性能，而且所添加的负极保护剂，在循环前与负极反应生成人工SEI保护层,在长循环过程中能够有效抑制锂枝晶生成和提高锂电池的循环稳定性。
以下为具体实施例部分：
实施例1
本实例提供的阻燃液态电解质包括按体积比计的以下组分：35%的基础电解质、60%的商业电解质以及5%的氟代碳酸乙烯酯，通过充分混合均匀形成阻燃液态电解质。其中，所述的基础电解质是将双氟磺酰亚胺锂溶于磷酸三甲酯溶剂形成的基础电解质，在所述的基础电解质中，双氟磺酰亚胺锂的摩尔分数为5mol/L.
本实施例中的阻燃聚合物凝胶电解质及锂电池的制备方法如下：
（1）、将2.3384g双(氟磺酰)亚胺锂溶于2 .5mL的磷酸三甲酯溶剂中，在室温度下充分搅拌至所述双(氟磺酰)亚胺锂完全溶解形成高浓度锂盐的基础电解质，所述基础电解质中，双(氟磺酰)亚胺锂的摩尔浓度为5mol/L。
（2）、移取0.1ml氟代碳酸乙烯酯溶液加入到1.2ml的商业电解质，在室温下充分搅拌均匀，形成第一溶液。
（3）、移取0.7ml所述的基础电解质加入步骤（2）中，在室温下充分搅拌均匀，形成所述的阻燃液态电解质。
（4）、将正极材料和负极材料分别贴合在所述的阻燃液态电解质两面，并加热聚合，得到所述锂电池。
将碎布条浸泡在本发明实施例阻燃液态电解质中，待其完全浸湿，进行点火实验，在明火燃烧数分钟的情况下，碎布条依旧未燃烧试验，说明本实施例提供的阻燃液态电解质具有很好的阻燃的阻燃性能。
实施例2
本实例提供的阻燃液态电解质包括按体积比计的以下组分：45%的基础电解质、40%的商业电解质以及15%的碳酸乙烯亚乙酯，通过充分混合均匀形成阻燃液态电解质。其中，所述的基础电解质是将双氟磺酰亚胺锂溶于磷酸三甲酯溶剂形成的基础电解质，在所述的基础电解质中，双氟磺酰亚胺锂的摩尔分数为7mol/L.
本实施例中的阻燃聚合物凝胶电解质的制备方法如下：
（1）、将3.3g双(氟磺酰)亚胺锂溶于2 .5mL的磷酸三乙酯溶剂中，在室温度下充分搅拌至所述双(氟磺酰)亚胺锂完全溶解形成高浓度锂盐的基础电解质，所述基础电解质中，双(氟磺酰)亚胺锂的摩尔浓度为7mol/L。
（2）、移取0.3ml碳酸乙烯亚乙酯溶液加入到0.8ml的商业电解质，在室温下充分搅拌均匀。
（3）、移取0.9ml所述的基础电解质加入步骤（2）中，在室温下充分搅拌均匀，形成所述的阻燃液态电解质。
（4）、将正极材料和负极材料分别贴合在所述的阻燃液态电解质两面，并加热聚合，得到所述锂电池。
将碎布条浸泡在本发明实施例阻燃液态电解质中，待其完全浸湿，进行点火实验，在明火燃烧数分钟的情况下，碎布条依旧未燃烧试验，说明本实施例提供的阻燃液态电解质具有很好的阻燃的阻燃性能。
实施例3
本实例提供的阻燃液态电解质包括按体积比计的以下组分：40%的基础电解质、50%的商业电解质以及10%的氟代碳酸乙烯酯，通过充分混合均匀形成阻燃液态电解质。其中，所述的基础电解质是将六氟磷酸锂溶于磷酸三甲酯溶剂形成的基础电解质，在所述的基础电解质中，六氟磷酸锂的摩尔分数为3mol/L.
本实施例中的阻燃聚合物凝胶电解质的制备方法如下：
（1）、将1.1325g六氟磷酸锂溶于2 .5mL的磷酸三甲酯溶剂中，在室温度下充分搅拌至所述双(氟磺酰)亚胺锂完全溶解形成高浓度锂盐的基础电解质，所述基础电解质中，双(氟磺酰)亚胺锂的摩尔浓度为3mol/L。
（2）、移取0.2ml氟代碳酸乙烯酯溶液加入到1.0ml的商业电解质，在室温下充分搅拌均匀。
（3）、移取0.8ml所述的基础电解质加入步骤（2）中，在室温下充分搅拌均匀，形成所述的阻燃液态电解质。
（4）、将正极材料和负极材料分别贴合在所述的阻燃液态电解质两面，并加热聚合，得到所述锂电池。
将碎布条浸泡在本发明实施例阻燃液态电解质中，待其完全浸湿，进行点火实验，在明火燃烧数分钟的情况下，碎布条依旧未燃烧试验，说明本实施例提供的阻燃液态电解质具有很好的阻燃的阻燃性能。
实施例4
本实例提供的阻燃液态电解质包括按体积比计的以下组分：35%的基础电解质、45%的商业电解质以及20%的碳酸乙烯亚乙酯，通过充分混合均匀形成阻燃液态电解质。其中，所述的基础电解质是将双三氟甲烷磺酰亚胺锂溶于磷酸三乙酯溶剂形成的基础电解质，在所述的基础电解质中，双三氟甲烷磺酰亚胺锂的摩尔分数为5mol/L.
本实施例中的阻燃聚合物凝胶电解质的制备方法如下：
（1）、将2.3g六氟磷酸锂溶于2 .5mL的磷酸三甲酯溶剂中，在室温度下充分搅拌至所述双(氟磺酰)亚胺锂完全溶解形成高浓度锂盐的基础电解质，所述基础电解质中，双(氟磺酰)亚胺锂的摩尔浓度为5mol/L。
（2）、移取0.4ml碳酸乙烯亚乙酯溶液加入到0.9ml的商业电解质，在室温下充分搅拌均匀。
（3）、移取0.7ml所述的基础电解质加入步骤（2）中，在室温下充分搅拌均匀，形成所述的阻燃液态电解质。
（4）、将正极材料和负极材料分别贴合在所述的阻燃液态电解质两面，并加热聚合，得到所述锂电池。
本发明实施例将以上提供的阻燃液态电解质组装在锂电池中，以进行电化学测试，具体如下：
具体的电池结构采用纽扣式电池，其包括正极、负极以在所述正极和负极指教的隔膜和电解质。其中负极采用锂金属电极或者是在同集流体上涂覆的石墨，石墨烯等负极材料组成的电极片，正极采用在铝箔集流体上涂覆磷酸铁锂形成的电极片，隔膜采用聚丙烯类隔膜，并进行电化学测试，获得以下实验结果。
对比例：将碎布条浸泡在传统的商业液态电解质中，待其完全浸湿，进行点火实验，碎布条瞬间燃烧起来。
而本实施例1-4提供的阻燃液态电解质，将碎布条浸泡在本发明实施例阻燃液态电解质中，待其完全浸湿，进行点火实验，在明火燃烧数分钟的情况下，碎布条依旧未燃烧。说明本发明所提供的电解质具有很好的阻燃性。
图3示出了本实施例1样品在0.5C的倍率下充放电曲线图，从图3可以看出，电池在0.5C的倍率下循环150次后容量高达146mAh/g，库伦效率达到99.3%。
图4示出了本实施例3样品在0.5C的倍率下充放电曲线图，从图4可以看出本实施例3样品在0.5C的倍率下循环150次后容量高达124mAh/g,库伦效率达到99.1%。
以上仅为本发明的较佳实施例而已，仅具体描述了本发明的技术原理，这些描述只是为了解释本发明的原理，不能以任何方式解释为对本发明保护范围的限制。基于此处解释，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进，及本领域的技术人员不需要付出创造性的劳动即可联想到本发明的其他具体实施方式，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种阻燃液态电解质的制备方法，其特征在于，包括下述步骤：
    将锂盐与磷酸酯溶剂混合后形成基础电解质；
    将负极保护剂与商业电解质混合后形成第一溶液；及
    将所述的基础电解质和所述第一溶液混合形成所述阻燃液态电解质。
  2. 如权利要求1所述的阻燃液态电解质的制备方法，其特征在于，所述锂盐选自双(氟磺酰)亚胺锂、六氟磷酸锂、双三氟甲基磺酰亚胺锂、双乙二酸硼酸锂、草酸二氟硼酸锂、高氯酸锂和四氟硼酸锂中的至少一种。
  3. 如权利要求1所述的阻燃液态电解质的制备方法，其特征在于，在所述基础电解质中，所述锂盐的摩尔分数为3mol/L~7mol/L。
  4. 如权利要求1所述的阻燃液态电解质的制备方法，其特征在于，所述磷酸酯溶剂选自磷酸三甲酯和磷酸三乙酯中的一种或两种。
  5. 如权利要求1所述的阻燃液态电解质的制备方法，其特征在于，所述的负极保护剂为氟代碳酸乙烯酯、碳酸乙烯亚乙酯中的一种或两种。
  6. 如权利要求1所述的阻燃液态电解质的制备方法，其特征在于，所述的商业电解质包括以六氟磷酸锂为溶质，以碳酸乙烯酯或碳酸二乙酯或碳酸二甲酯中至少一种为溶剂。
  7. 如权利要求1所述的阻燃液态电解质的制备方法，其特征在于，在所述液态阻燃电解质中，所述基础电解质的体积百分比为35%-45%，所述商业电解质的体积百分比为40%-60% ，所述负极保护剂的体积百分比为为5％～20％。
  8. 一种阻燃液态电解质，其特征在于，由权利要求1-7任一项所述的阻燃液态电解质的制备方法制备而成。
  9. 一种锂电池的制备方法，其特征在于，包括下述步骤：将正极材料和负极材料分别贴合在权利要求8所述的阻燃液态电解质两面，并加热聚合，得到所述锂电池。
  10. 一种锂电池，其特征在于，包括权利要求8所述的阻燃液态电解质以及贴合在所述阻燃液态电解质两面的正极材料和负极材料。
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