Electrolyte and lithium ion battery

Abstract

The present invention relates to the technical field of battery materials, and in particular to an electrolyte, the electrolyte comprising a basic electrolyte and an electrolyte additive, the electrolyte additive being a molecular machine, the molecular machine comprising a functional motif A and a functional motif B; the functional motif A having a halogen bond donor, the functional motif B having a halogen bond receptor; the functional motif A and the functional motif B being combined through multiple intermolecular halogen bonds; the functional motif A and / or the functional motif B containing a basic functional group, the basic functional group comprising a nitrogen-containing functional group, a phosphorus-containing functional group, an ether bond or a double bond. The present invention also provides a lithium ion battery.

Description

[Technical field]

[0002] The present invention relates to the technical field of battery materials, and in particular to an electrolyte and a lithium ion battery. [Background technology]

[0004] Lithium batteries are an important type of electrical energy device, and are an important source of power and computing power for unmanned devices and smart devices in the future. However, in some extreme environments or special working conditions, such as extremely high temperatures, extremely low temperatures, overcharging, over-discharging, and high current charging / discharging, lithium batteries may experience safety failure accidents such as gas production, fire, and explosion, and the probability of performance degradation increases sharply. The lack of stability of lithium battery electrolytes in extreme environments or special working conditions is one of the main reasons for the above safety and performance failure risks. [Summary of the invention]

[0006] In order to solve the problem that the electrolyte of a lithium battery has insufficient stability under extreme environments or special working conditions, the present invention provides an electrolyte and a lithium ion battery.

[0007] In order to solve the above technical problems, the present invention provides an electrolyte, comprising a basic electrolyte and an electrolyte additive, wherein the electrolyte additive is a molecular machine, and the molecular machine comprises a functional element A and a functional element B;

[0008] The functional element A has a halogen bond donor, and the functional element B has a halogen bond receptor; the functional element A and the functional element B are combined through multiple halogen bonds between molecules;

[0009] The functional moiety A and / or the functional moiety B contain basic functional groups, and the basic functional groups include nitrogen-containing functional groups, phosphorus-containing functional groups, ether bonds or double bonds.

[0010] Preferably, the halogen bond acceptor is F, Cl, Br or I; and the halogen bond donor is N or O.

[0011] Preferably, the basic functional groups include carbonate, carboxylate, amide or urea groups.

[0012] Preferably, the chemical formula of the functional unit A is

[0013] ;

[0014] The functional unit B is perfluorohexanone or perfluorooctanone.

[0015] The functional motif A of the molecular machine is synthesized by amidation reaction, phospholipidation reaction and / or carboxylation reaction, and the molecular machine is obtained by dissolving the functional motif B and the functional motif A in a solution and performing self-assembly.

[0016] Preferably, the synthesis of the functional element A is specifically as follows:

[0017] .

[0018] The present invention also provides an electrolyte, comprising a basic electrolyte and an electrolyte additive, wherein the electrolyte additive is the above-mentioned molecular machine.

[0019] Preferably, the electrolyte additive accounts for 1-50% by weight.

[0020] The present invention also provides a lithium ion battery, comprising the above electrolyte.

[0021] Preferably, the lithium ion can work normally in the range of -90~80℃, and the -90℃ discharge capacity retention rate is ≥30%; and the autonomous flame retardant and self-extinguishing time is ≤1s / g, and the 5C discharge capacity retention rate is ≥80%.

[0022] Compared with the prior art, the molecular machine provided by the present invention combines functional elements through multiple halogen bonds between molecules, which can realize intelligent response to various physical fields such as temperature, electrochemical potential, electric field, and decoupling regulation of response characteristics, and is particularly suitable for use as an electrolyte additive for lithium batteries. For example, in the case of overheating, the molecular machine undergoes conformational changes, causing property changes, avoiding problems such as battery fire due to overheating; in low temperature conditions, the molecular machine undergoes conformational changes to ensure low temperature conductivity and improve the low temperature resistance of lithium batteries; when overcharge occurs, the molecular machine undergoes structural adjustments to avoid problems such as electrolyte decomposition or lithium dendrites; when over-discharge occurs, the molecular machine adjusts its charge distribution to prevent structural collapse caused by positive and negative electrode materials; when the lithium battery reaches the critical condition for ignition, the molecular machine undergoes structural adjustments to prevent the battery from catching fire; under high current conditions, the molecular machine undergoes polarity changes to prevent the battery from heating due to excessive current. The basic functional groups can ensure the basic functions of the electrolyte, such as dissociation of lithium salts, wettability, flame retardancy or film formation.

Brief Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the construction of the molecular machine in the present invention. [Specific implementation method]

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] First embodiment

[0028] See also Figure 1The present invention provides a molecular machine, comprising a functional motif A and a functional motif B. The functional motif A has a halogen bond donor, and the functional motif B has a halogen bond receptor; the functional motif A and the functional motif B are combined through multiple halogen bonds between molecules. The functional motif A and / or the functional motif B contain basic functional groups, and the basic functional groups include nitrogen-containing functional groups, phosphorus-containing functional groups, ether bonds or double bonds.

[0029] The functional elements of the molecular machine are combined through multiple halogen bonds between molecules, which can realize intelligent response to various physical fields such as temperature, electrochemical potential, electric field, and decoupled regulation of response characteristics, and are particularly suitable for use as electrolyte additives for lithium batteries. For example, in the case of overheating, the molecular machine undergoes conformational changes, causing property changes, avoiding problems such as battery fire due to overheating; in low temperature conditions, the molecular machine undergoes conformational changes to ensure low temperature conductivity and improve the low temperature resistance of lithium batteries; when overcharge occurs, the molecular machine undergoes structural adjustments to avoid problems such as electrolyte decomposition or lithium dendrites; when over-discharge occurs, the molecular machine adjusts its charge distribution to prevent structural collapse caused by positive and negative electrode materials; when the lithium battery reaches the critical condition for ignition, the molecular machine undergoes structural adjustments to prevent the battery from catching fire; under high current conditions, the molecular machine undergoes polarity changes to prevent the battery from heating due to excessive current. The basic functional groups can ensure the basic functions of the electrolyte, such as dissociation of lithium salts, wettability, flame retardancy or film formation. For example, nitrogen-containing functional groups and phosphorus-containing functional groups can provide flame retardant functions, and double bonds can provide film-forming functions.

[0030] Preferably, the halogen bond receptor is an electron-deficient halogen atom such as F, Cl, Br, I, among which F is preferred. The halogen bond donor is preferably N or O. The halogen bond donor and the halogen bond receptor can specifically bind (such as Figure 1 shown by the dashed line).

[0031] Preferably, the basic functional groups include carbonate, carboxylate, amide or urea. Carbonate and carboxylate have ether bonds, which can ensure the dissociation of lithium salts and wettability of the electrolyte; amide and urea have nitrogen-containing functional groups and carbon-oxygen double bonds, wherein the nitrogen-containing functional groups can provide flame retardant functions, and the carbon-oxygen double bonds can not only provide film-forming groups but also serve as halogen bond donors. It can be understood that the halogen bond donors or halogen bond receptors possessed by the functional unit can also be basic functional groups in some cases, such as the above-mentioned amide and urea groups.

[0032] In some preferred embodiments, the functional motif A also has a halogen bond receptor, so that the functional motifs in the molecular machine are not only combined in pairs, but also can be combined in groups or clusters.

[0033] In some specific embodiments, preferably, the chemical formula of the functional unit A is

[0034]

[0035] As can be seen from the chemical formula, it not only has halogen bond donors (N, O), halogen bond acceptors (fluorine), but also basic functional groups (ether bonds, N, P, double bonds). In this way, on the basis of being able to form multiple halogen bonds with other functional elements, it can also well guarantee the basic functions of the electrolyte, including dissociation of lithium salts, wettability, flame retardancy and film formation.

[0036] Preferably, the functional unit B is perfluorohexanone or perfluorooctanone, which has a plurality of electron-deficient Fs.

[0037] Second embodiment

[0038] The present invention provides a method for preparing a molecular machine as described in the first embodiment, comprising synthesizing a functional moiety A through an amidation reaction, a phospholipidation reaction and / or a carboxylation reaction, providing a functional moiety B and a functional moiety A dissolved in a solution for self-assembly to obtain the desired molecular machine.

[0039] It can be understood that since the functional element has a halogen bond donor and a halogen bond receptor, it can be spontaneously assembled and self-driven after being dissolved in a solution, and the process does not require external heating and other conditions. Functional element A can obtain the required halogen bond donor through amidation reaction, phospholipidation reaction and / or carboxylation reaction, or obtain the required halogen bond donor and basic functional group at the same time.

[0040] In some specific embodiments, preferably, the synthesis of the functional element A is specifically as follows:

[0041] .

[0042] The synthesis method of the functional unit A is simple and effective.

[0043] Third embodiment

[0044] The present invention further provides an electrolyte, comprising a basic electrolyte and an electrolyte additive, wherein the electrolyte additive is the molecular machine in the first embodiment.

[0045] Preferably, the electrolyte additive accounts for 1-50% by weight. In some specific embodiments, the base electrolyte is preferably a carbonate electrolyte or an ether electrolyte.

[0046] Fourth embodiment

[0047] The present invention further provides a lithium ion battery, comprising the electrolyte in the third embodiment.

[0048] Preferably, the lithium ion battery can work normally in the range of -90~80℃, the -90℃ discharge capacity retention rate is ≥30%; the self-flaming self-extinguishing time is ≤1s / g, and the 5C discharge capacity retention rate is ≥80%. In addition, the lithium ion battery will not have thermal runaway below 500℃, and has the advantages of no gas generation in overcharging and no attenuation in overdischarging.

[0049] It should be understood that the "one embodiment" or "an embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. Those skilled in the art should also be aware that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0050] The above is a detailed introduction to a molecular machine and its preparation method, electrolyte, and lithium-ion battery disclosed in the embodiments of the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention. Any modifications, equivalent substitutions and improvements made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An electrolyte, comprising a basic electrolyte and an electrolyte additive, characterized in that: The electrolyte additive is a molecular machine, and the molecular machine includes a functional unit A and a functional unit B; The functional element A has a halogen bond donor, and the functional element B has a halogen bond receptor; The functional element A is combined with the functional element B through multiple halogen bonds between molecules; The functional moiety A and / or the functional moiety B contain basic functional groups, and the basic functional groups include nitrogen-containing functional groups, phosphorus-containing functional groups, ether bonds or double bonds.

2. The electrolyte according to claim 1, characterized in that: The halogen bond receptor is F, Cl, Br or I; the halogen bond donor is N or O.

3. The electrolyte according to claim 1, characterized in that: The basic functional groups include carbonate, carboxylate, amide or urea groups.

4. The electrolyte according to claim 1, characterized in that: The chemical formula of the functional unit A is ； The functional unit B is perfluorohexanone or perfluorooctanone.

5. The electrolyte according to claim 1, characterized in that: The functional motif A is synthesized by amidation reaction, phospholipidation reaction and / or carboxylation reaction, and the molecular machine is obtained by dissolving the functional motif B and the functional motif A in a solution for self-assembly.

6. The electrolyte according to claim 5, characterized in that: The synthesis of the functional element A is specifically as follows: 。 7. The electrolyte according to claim 1, characterized in that: The electrolyte additive accounts for 1-50% by weight.

8. A lithium ion battery, characterized in that: Comprising the electrolyte as described in any one of claims 1-7.

9. The lithium-ion battery according to claim 8, characterized in that: It can work normally in the range of -90~80℃, and the -90℃ discharge capacity retention rate is ≥30%; and the autonomous flame retardant and self-extinguishing time is ≤1s / g, and the 5C discharge capacity retention rate is ≥80%.

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