阅读说明：本技术 一种匹配高镍正极材料锂离子电池的高温高压电解液 (A kind of high-temp. high-pressure electrolysis liquid matching nickelic positive electrode lithium ion battery ) 是由 陈仕谋 冯冬瑾 闫淑欣 刘玉文 张锁江 于 2019-09-17 设计创作，主要内容包括：本发明涉及锂离子电池领域,公开了一种匹配高镍正极材料锂离子电池的高温高压电解液。所述电解液包括复合锂盐,有机溶剂,所述锂盐为六氟磷酸锂和二氟草酸硼酸锂,有机溶剂为碳酸乙烯酯和碳酸甲乙酯。本发明的锂离子电池电解液在高温60℃,循环100圈后容量保持率达到89.0％并且不影响其常温循环性能。此外,使用高镍正极材料进行高压4.5V测试,60次循环后容量保持率高达86.7％。该复合锂盐电解液可以在NCM811表面形成稳定、致密的CEI膜,使得材料结构不容易破环,并且提高了高镍三元NCM811材料在高温高压下的循环稳定性,大大增加了锂离子电池的应用范围。(The present invention relates to field of lithium ion battery, disclose a kind of high-temp. high-pressure electrolysis liquid for matching nickelic positive electrode lithium ion battery.The electrolyte includes compound lithium salts, and organic solvent, the lithium salts is lithium hexafluoro phosphate and difluorine oxalic acid boracic acid lithium, and organic solvent is ethylene carbonate and methyl ethyl carbonate.Lithium-ion battery electrolytes of the invention are at 60 DEG C of high temperature, and capacity retention ratio reaches 89.0% and do not influence its normal-temperature circulating performance after 100 circle of circulation.In addition, carrying out high pressure 4.5V test using nickelic positive electrode, capacity retention ratio is up to 86.7% after 60 circulations.The compound lithium salt electrolyte can form stable, fine and close CEI film on the surface NCM811, so that material structure does not allow fragile ring, and the cyclical stability of nickelic ternary NCM811 material at high temperature under high pressure is improved, the application range of lithium ion battery is considerably increased.)

1. a kind of high-temp. high-pressure electrolysis liquid for matching nickelic positive electrode lithium ion battery, which is characterized in that the high temperature and pressure Safety electrolyte includes lithium salts and Non-aqueous Organic Solvents, wherein the lithium salts is the mixing of lithium hexafluoro phosphate and other lithium salts The total concentration of object, lithium salts remains 0.8~1.5mol/L.

2. the high-temp. high-pressure electrolysis liquid of the nickelic positive electrode lithium ion battery of matching according to claim 1, feature exist In: the positive electrode, conductive agent, binder ratio include but are not limited only to 8:1:1,9:0.5:0.5.

3. the high-temp. high-pressure electrolysis liquid of the nickelic positive electrode lithium ion battery of matching according to claim 1, feature exist Be selected from lithium hexafluoro phosphate in: the lithium salts, di-oxalate lithium borate, double fluorine Lithium bis (oxalate) borates and double fluorine sulfimide lithiums it is any One or two combination.

4. the high-temp. high-pressure electrolysis liquid of the nickelic positive electrode lithium ion battery of matching according to claim 1, feature exist In: the organic solvent is in ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate, adiponitrile, succinonitrile, ethyl acetate It is one or more.

5. the high-temp. high-pressure electrolysis liquid of the nickelic positive electrode lithium ion battery of matching according to claim 4, feature exist In: the lithium ion battery is Li-Ni-Co-Mn system, preferably Li (Ni_0.8Co_0.1Mn_0.1)O₂。

6. a kind of lithium ion battery, including anode, cathode, diaphragm and electrolyte, it is characterised in that: weighed including above-mentioned any one Benefit requires the high temperature and pressure safety electrolyte.

7. lithium-ion battery electrolytes according to claim 6, it is characterised in that: the survey of the lithium-ion battery electrolytes Trying temperature is room temperature to 60 DEG C.

8. lithium-ion battery electrolytes according to claim 6, it is characterised in that: the lithium ion battery is surveyed under high pressure Examination, end of charge voltage are not less than 4.3V.

Technical field

The invention belongs to field of lithium ion battery, it is specifically related to match nickelic positive electrode lithium ion battery to a kind of High-temp. high-pressure electrolysis liquid.

Background technique

Lithium ion battery because its energy density is big, have extended cycle life, power density is high, environmental pollution is small the advantages that, not only It is widely used in portable electronic device, and is increasingly becoming the main power source of electric car.However, power electric in recent years The accident that the fire that pond is caused even explodes has been reported that the safety problem of lithium ion battery causes the extensive concern of people repeatly.

At present in lithium ion battery applications, nickelic tertiary cathode material is at low cost with its, and energy density is higher, tap density The advantages that high, has become the theme of power battery industry development in recent years, and battery enterprise is for nickelic tertiary cathode material Importing is in urgent need, but there is also many problems for nickelic positive electrode, such as cyclical stability compares at high temperature under high pressure Difference, and the decomposition at high temperature under high pressure of the electrolyte based on lithium hexafluoro phosphate and electrolyte and anode and negative electrode material surface Side reaction be also to lead to the principal element of capacitance loss.In short, the compatibility of existing electrolyte and nickelic positive electrode is poor, How to improve the cyclical stability of nickelic positive electrode at high temperature under high pressure and has become difficult point urgently to be resolved.

Summary of the invention

It is a primary object of the present invention to from lithium salts, according to the structure of different lithium salts, performance characteristics are selected The lithium salts of suitable high-temperature-resistant high-pressure-resistant prepares compound lithium salt electrolyte, provides a kind of nickelic positive electrode lithium ion battery of matching High-temp. high-pressure electrolysis liquid, with overcome the deficiencies in the prior art.

To achieve the above object, The technical solution adopted by the invention is as follows:

A kind of high-temp. high-pressure electrolysis liquid matching nickelic positive electrode lithium ion battery, including lithium salts and solvent.It is wherein multiple Closing lithium salts total concentration in the electrolytic solution is 0.8~1.5mol/L, single lithium salts the concentration of electrolyte be 0.2mol/L~ 1.0mol/L。

Preferably, the lithium salts is lithium hexafluoro phosphate and double fluorine Lithium bis (oxalate) borate one or two combinations.

Preferably, the solvent is one of ethylene carbonate, diethyl carbonate, methyl ethyl carbonate, dimethyl carbonate Or two kinds.The organic solvent accounts for 10~90wt% of lithium-ion battery electrolytes gross mass.

Lithium salts is added in the mixed solvent and reduces the generation of side reaction in order to dissolve lithium salts sufficiently, configured electrolyte It afterwards, should be by its static 4h.

The beneficial effect of above scheme is: by using compound lithium salt electrolyte provided by the invention, can make nickelic Positive electrode keeps good stability at high temperature, reduces the generation of the side reaction under high temperature between electrolyte and electrode, And improve the cycle performance of battery under high pressure.

Detailed description of the invention

Fig. 1 is that the embodiment of the present invention 1 and 1 electrolyte of comparative example recycle the cycle performance song after 100 circles at normal temperature Line.

Fig. 2 is that the embodiment of the present invention 4 and 2 electrolyte of comparative example recycle the cycle performance song after 100 circles at high temperature Line.

Fig. 3 is that the embodiment of the present invention 7 and 3 electrolyte of comparative example recycle the cycle performance song after 60 circles under high pressure Line.

Specific embodiment

It elaborates below with reference to specific embodiment to the present invention.It is all to the present invention modify without departing from It should all include within the protection scope of the present invention under the embodiment of the present invention principle.

The preparation of positive electrode: by Li (Ni_0.8Co_0.1Mn_0.1)O₂Powder: conductive black: polyvinylidene fluoride is according to 8:1: 1 mass ratio mixing, is added suitable NMP, stirs evenly and be coated on aluminium foil, is put into 80 DEG C of air dry oven dry 12h, After being compacted with tablet press machine, it is cut into the pole piece of 14mm, and be dried in vacuo 12h at 80 DEG C.Glove box is put into after weighing.

Anode pole piece: being put into the middle position of negative electrode casing by the assembling of button cell, then draws a small amount of electrolysis with dropper Liquid, drop 2-3 are dripped on pole piece, put diaphragm, then drip 3-4 drop electrolyte, one are placed on lithium piece is smoother on battery down, Then nickel foam and negative electrode casing are put, finally suppresses battery to 550Kpa with battery sealing machine.It is assembled into CR2025 battery, is stood It is tested after 10h.

The electrolyte configured below is added in button cell.

(1) normal-temperature circulating performance is evaluated