Multi-block copolymer and method for producing same, electrolyte composition, binder composition, buffer composition, lithium ion battery

Abstract

The present invention addresses the problem of providing a novel polymer (multi-block copolymer) which has an ability equivalent to the conductivity of a liquid electrolyte, has excellent adhesion between an inorganic electrolyte and an electrode, and is safe and highly stable. The solution of the present invention is to prepare a multi-block copolymer in which two or more unit structures, each of which is obtained by bonding a soft segment comprising polyglycidyl (PGLYD) and a hard segment comprising polyethylene glycol (PEG), are linked.

Description

Technical Field

[0001] This invention relates to multiblock copolymers and their manufacturing methods, compositions for electrolytes, compositions for adhesives, compositions for buffers, and lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries are lightweight, miniaturized, high-energy-density, and fast-charging-discharging general-purpose batteries, and are therefore widely used in mobile phones, small household appliances, and other applications.

[0003] When lithium-ion batteries are used in portable devices, physical damage during movement can sometimes allow moisture to enter the liquid electrolyte, such as ethylene carbonate. In such cases, the moisture can cause metallic lithium deposited during charging and discharging to react, potentially leading to a fire or explosion. Furthermore, current lithium-ion batteries cannot be used in extremely low-temperature environments or at temperatures exceeding the boiling point of organic electrolytes. Therefore, solid electrolytes, which have low flammability and are less affected by operating temperature, are gaining significant attention as a replacement for liquid electrolytes.

[0004] As solid electrolytes, either inorganic or organic electrolytes are used. Specifically, inorganic electrolytes utilize sulfides and oxides. Organic electrolytes utilize polyethylene glycol (PEG), polyvinyl carbonate (PEC), and other materials with ether bonds that facilitate lithium-ion conductivity. Inorganic electrolytes are manufactured through high-temperature sintering, but cracks can sometimes occur under operating conditions, leading to a decrease in conductivity. On the other hand, PEG, used as an organic electrolyte, has attracted attention due to its characteristics not found in inorganic electrolytes. However, PEG is a crystalline polymer, and crystallization can block lithium conduction pathways, reducing lithium-ion conductivity to as low as 10. -8 S / cm. In addition, PEC is an amorphous polymer with a higher lithium-ion transport rate than PEG, but it has a low film-forming ability and is difficult to process.

[0005] In addition, PEG has a melting point of 55°C, therefore, above this temperature, its lithium-ion conductivity remains at 100%. -4 S / cm, but in order for the solid electrolyte to be usable at room temperature, the polymer needs to be non-crystallizable.

[0006] To suppress PEG crystallization, methods have been developed using branched PEG (Non-Patent Document 1), hydrogels (Patent Document 1), or inorganic additives such as montmorillonite or silica gel. However, methods using branched PEG are cumbersome, and for hydrogels, the polymer's mechanical strength is too low for practical use. Furthermore, the materials used in these methods lack adhesiveness and cannot effectively fill the gap between the inorganic electrolyte and the electrode.

[0007] On the other hand, as an alternative to PEG, polyglycidyl ether (PGLYD) has been proposed as a lithium-ion electrolyte (Patent Document 2). Due to the high amorphous nature of PGLYD, high lithium-ion conductivity is achieved.

[0008] Glycidyl is a compound obtained by removing one molecule of water from glycerol. Glycidyl is a hydroxymethyl ethylene oxide and, like ethylene oxide, can undergo ring-opening polymerization. PEG can be generated from ethylene oxide, and polyglycidyl (PGLYD) can be generated from glycidyl. PGLYD has the same polyethylene oxide chain as PEG, but due to the presence of the hydroxymethyl group, it exhibits random branching. Therefore, PEG and PGLYD have the same carbon-to-oxygen ratio, but PGLYD has the problem of not being able to crystallize. Therefore, PGLYD cannot be used as a solid electrolyte.

[0009] Existing technical documents

[0010] Non-patent literature

[0011] Non-patent literature 1: Naoya Ogata, Journal of the Fiber Society, pp. 52-57, 1990.

[0012] Non-patent literature 2: H. Frey et al., J. Am. Chem. Soc. 2009, 131, 23, 7954-7955.

[0013] Patent documents

[0014] Patent document 1: Japanese Patent Application Publication No. 5-25353.

[0015] Patent Document 2: International Publication No. WO00 / 35991. Summary of the Invention

[0016] The problem that the invention aims to solve

[0017] Compared to existing technologies, there is a need to develop technologies with conductivity comparable to liquid electrolytes (10). -3 A safe and stable solid electrolyte with a capacity comparable to (S / cm).

[0018] In particular, there is a desire to develop a solid electrolyte capable of bonding the inorganic electrolyte to the electrodes. In existing technologies, strong pressure is required to secure the two materials together and eliminate gaps between the inorganic electrolyte and the electrodes, necessitating the use of a heavy container to cover the battery. Using an adhesive electrolyte would eliminate the need for such a large container. Furthermore, if an adhesive electrolyte is used, it can penetrate into any gaps caused by cracks in the inorganic electrolyte during use, thus preventing battery degradation.

[0019] The present invention was made in view of the above circumstances, and its objective is to provide a novel polymer (multiblock copolymer) and a method for manufacturing the same, which possesses conductivity comparable to that of a liquid electrolyte, excellent adhesion between the inorganic electrolyte and the electrode, and excellent safety and stability. Furthermore, the present invention also aims to provide electrolyte compositions, adhesive compositions, and buffer compositions comprising this polymer. Further, the present invention aims to provide lithium-ion batteries comprising these compositions.

[0020] Methods for solving problems

[0021] To address the aforementioned issues, the following multiblock copolymers, methods for their manufacture, compositions for electrolytes, compositions for adhesives, and compositions for cushioning are provided.

[0022] [1] A multiblock copolymer, wherein, The connection consists of two or more unit structures, which are formed by bonding soft segments of polyglycidyl ether (PGLYD) to hard segments of polyethylene glycol (PEG).

[0023] [2] A multiblock copolymer as described in [1], wherein, The weight-average molecular weight of the multiblock copolymer is above 10,000.

[0024] [3] A multiblock copolymer as described in [1] or [2], wherein, The multiblock copolymer has lithium-ion conduction pathway groups.

[0025] [4] An electrolyte composition, which is an electrolyte composition for lithium-ion batteries, wherein, The electrolyte composition comprises a multiblock copolymer of any one of [1] to [3].

[0026] [5] An adhesive composition for use in lithium-ion batteries, wherein, The adhesive composition comprises a multiblock copolymer of any one of [1] to [3].

[0027] [6] A buffer composition, which is a buffer composition for lithium-ion batteries, wherein, The buffer composition comprises a multiblock copolymer of any one of [1] to [3].

[0028] [7] A lithium-ion battery, wherein the lithium-ion battery comprises at least one of the electrolyte composition of [4], the binder composition of [5], and the buffer composition of [6].

[0029] [8] A method for manufacturing a multiblock copolymer, which is the method for manufacturing the multiblock copolymer of [1], wherein, The method for manufacturing the multiblock copolymer includes the following steps: The process of reacting polyethylene glycol (PEG) with isocyanate groups at both ends with poly(2,3-epoxypropyl-1-ethoxyethyl ether) (polyEEGE, i.e., PEEGE) to synthesize a compound represented by the following chemical formula (1); and The process of reacting an acid with the compound to synthesize a multiblock copolymer represented by the following chemical formula (2),

[0030] (In formula (1), l is a natural number greater than 2)

[0031] (In formula (2), l is a natural number greater than 2).

[0032] [9] A method for manufacturing a multiblock copolymer, which is the method for manufacturing the multiblock copolymer of [1], wherein, The method for manufacturing the multiblock copolymer includes: The process of reacting PEG, poly(2,3-epoxypropyl-1-ethoxyethyl ether) (polyEEGE, i.e., PEEGE), and a diisocyanate compound with hydroxyl groups at both ends to synthesize a compound represented by the following chemical formula (1); and The process of reacting an acid with the compound to synthesize a multiblock copolymer represented by the following chemical formula (2),

[0033] (In formula (1), l is a natural number greater than 2)

[0034] (In formula (2), l is a natural number greater than 2).

[0035] The effects of the invention

[0036] The multiblock copolymer of the present invention exhibits conductivity comparable to that of a liquid electrolyte, excellent adhesion between the inorganic electrolyte and the electrode, and excellent safety and stability. Therefore, this multiblock copolymer can be suitably used in electrolyte compositions, adhesive compositions, and buffer compositions for lithium-ion batteries.

[0037] The lithium-ion battery of the present invention comprises at least one of an electrolyte composition, an adhesive composition, and a buffer composition, and has a conductivity comparable to that of a liquid electrolyte, excellent adhesion between the inorganic electrolyte and the electrode, and excellent safety and stability.

[0038] Furthermore, the method for manufacturing the multiblock copolymer according to the present invention enables the simple and stable manufacture of the aforementioned multiblock copolymer. Attached Figure Description

[0039] Figure 1 This is a schematic cross-sectional view illustrating one embodiment of the lithium-ion battery of the present invention.

[0040] Figure 2 It shows EEGE 1 Figure of H NMR spectrum (400MHz, CDCl3).

[0041] Figure 3 This is a graph showing the FT-IR spectrum of PEEGE.

[0042] Figure 4 (a) shows the polymer solution 1 The 1H NMR spectrum, Figure 4 (b) shows the obtained polymer. 1 The figure of H NMR spectrum.

[0043] Figure 5 This is a graph showing the FT-IR spectrum of PEG-PEEGE.

[0044] Figure 6 It shows PEG, PEEGE and PEG-PEEGE. 1 The figure of H NMR spectrum.

[0045] Figure 7 The image shows the IR spectra of PEG-PGLYD and PEG-PEEGE.

[0046] Figure 8 It shows PEG-PEEGE and PEG-PGLYD. 1 The figure of H NMR spectrum.

[0047] Figure 9 This is a schematic diagram illustrating one method of manufacturing the multiblock copolymer of the present invention.

[0048] Figure 10 The figure shows the results of observing the solubility when 1.5 g of the synthesized multiblock copolymer was added to 3 mL of NMP and stirred at room temperature for 24 hours.

[0049] Figure 11 The graph shows the adhesion of an NMP solution coated with a multiblock copolymer and dried.

[0050] Figure 12 This diagram illustrates a cathode material prepared by mixing a multi-block copolymer NMP solution with ferric phosphate containing a conductive material, coating it onto aluminum foil, and then drying and pressing it.

[0051] Figure 13 This shows the use of positive electrode materials ( Figure 12 The graph shows the results of punching the batteries to the size of coin-shaped batteries and examining the initial charge and discharge characteristics of the manufactured batteries.

[0052] Figure 14 This shows the use of positive electrode materials ( Figure 12 A graph showing the results of cyclic testing of batteries made by punching them to coin-shaped dimensions. Detailed Implementation

[0053] The following describes one embodiment of the multiblock copolymer and its manufacturing method of the present invention. It should be noted that in the following description, "PEEGE-PEG" and "PEG-PEEGE" have the same definition, and "PGLYD-PEG" and "PEG-PGLYD" have the same definition.

[0054] The multiblock copolymer of the present invention is designed with regard to the amorphous nature of glycidyl ether (PGLYD) and the crystallinity of polyethylene glycol (PEG). The multiblock copolymer of the present invention is a multiblock copolymer comprising PGLYD and PEG, where PGLYD functions as a soft segment capable of flowing across the entire temperature range, and PEG functions as a hard segment that crystallizes below 60°C. That is, the multiblock copolymer of the present invention connects two or more unit structures (PGLYD-PEG), which are formed by bonding soft segments composed of glycidyl ether (PGLYD) with hard segments composed of polyethylene glycol (PEG). In other words, the multiblock copolymer of the present invention contains four or more segments (soft and hard segments).

[0055] The number of unit structures (PGLYD-PEG) in the multiblock copolymer of the present invention is not particularly limited, and from the viewpoint of electrolyte conductivity and adhesion (viscosity), for example, a range of 4 to 100 can be cited.

[0056] It should be noted that triblock copolymers of PGLYD-PEG are known, published by Frey et al. in 2009 (Non-Patent Literature 2), but multiblock copolymers of PGLYD-PEG with four or more segments (blocks) were previously unknown. Furthermore, compared to conventional methods for manufacturing triblock copolymers, the molecular weight of the multiblock copolymer of this invention can be easily increased using the manufacturing method of the present invention, resulting in easier materialization. Another key feature of the multiblock copolymer of this invention is the stable phase separation of the hard segments of PEG and the soft segments of PGLYD, resulting in the multiblock copolymer serving as a good elastomer and adhesive material.

[0057] Preferably, both the PGLYD and PEG segments constituting the multiblock copolymer of the present invention have lithium-ion conduction pathway groups. Furthermore, the multiblock copolymer of the present invention exhibits an elastomer behavior at temperatures below 60°C (e.g., the temperature range for battery manufacturing) due to the presence of soft / hard segments, thus functioning as an adhesive.

[0058] As a summary, the following steps can be used to illustrate a first method for manufacturing the multiblock copolymer of the present invention.

[0059] (1) About PEG

[0060] PEG with a weight-average molecular weight in the range of 10,000 to 20,000 can be synthesized using known methods. The two terminal hydroxyl groups of PEG can be reacted, for example, with a compound such as hexamethylene diisocyanate to convert the ends into isocyanate groups, resulting in an A2-type macromonomer. That is, PEG with isocyanate groups at both ends can be synthesized.

[0061] (2) Regarding PGLYD

[0062] For example, the hydroxymethyl group of glycidyl ether (EEGE) is protected with ethyl vinyl ether or the like. Then, this EEGE is polymerized in the presence of a HO-R-OH diol, such as tetraethylene glycol or pentaerythritol, as a polymerization initiator. This converts it into a precursor of PGLYD, becoming a macromonomer of type B2 or B4. This precursor has terminal hydroxyl groups.

[0063] (3) Regarding multiblock copolymers (PGLYD / PEG block copolymers)

[0064] The PEG with two terminal isocyanate groups in (1) and the precursor in (2) are heated in the presence of a tin-based catalyst to induce multi-block copolymerization. The protection is then removed, for example, by using hydrogen chloride gas, hydrochloric acid, or a hydrochloric acid-methanol solution. This yields a multi-block copolymer containing PGLYD and PEG. The multi-block copolymer is composed of two or more unit structures (PGLYD-PEG), which are formed by bonding soft segments of polyglycidyl (PGLYD) to hard segments of polyethylene glycol (PEG). The multi-block copolymer is a polymer with four or more segments (polymer blocks), preferably a polymer with about 4 to 20 segments (polymer blocks).

[0065] That is, for the multiblock copolymer of the present invention, there are two or more unit structures (PGLYD-PEG) connected by PGLYD and PEG, represented by the following chemical formula (2).

[0066]

[0067] In the formula, l is a natural number greater than 2, typically ranging from 4 to 100.

[0068] Of course, the present invention is not limited to the methods described above, and various methods and knowledge known can be considered to select different approaches.

[0069] The weight-average molecular weight (Mw) of the multiblock copolymer of the present invention is not particularly limited to a range, for example, it is 2000 or more. However, considering the preferred conductivity and adhesion in lithium-ion batteries, the weight-average molecular weight of the polymer compound of the present invention is preferably in the range of 10,000 to 1,000,000. When the weight-average molecular weight of the multiblock copolymer is less than 10,000, a self-supporting film may sometimes not be formed. When the weight-average molecular weight of the multiblock copolymer is greater than 1,000,000, the processability may sometimes decrease due to high viscosity. Furthermore, when the weight-average molecular weight of the multiblock copolymer is greater than 50,000, the film containing the multiblock copolymer can be given toughness; furthermore, if the molecular weight is between 50,000 and 1,000,000, the durability of the film can be improved.

[0070] The number-average molecular weight (Mn) range of the multiblock copolymer of the present invention can be appropriately adjusted by selecting the molecular weights of PEG and PGLYD (precursors) and the reaction conditions for block copolymerization. Specifically, the number-average molecular weight of the multiblock copolymer of the present invention can be 1000 or more, preferably in the range of 5000 to 500000.

[0071] The multiblock copolymer of the present invention can possess lithium-ion conduction pathway groups. These lithium-ion conduction pathway groups can be various groups primarily composed of terminal hydroxyl groups, such as nitrile groups and ammonium groups. For example, as described in Patent Document 2, lithium conductivity can be improved by converting a portion of the hydroxyl groups in PGLYD to nitrile groups and increasing the polarity of the polymer. Furthermore, high lithium-ion conductivity can be imparted by converting residual hydroxyl groups to an imidazolium salt having a bis(trifluorosulfonyl)imide anion and doping it with lithium perchlorate.

[0072] The PGLYD and PEG that constitute the unit structure of the multiblock copolymer of the present invention can have various substituents. Examples of substituents include hydroxyl, nitrile, ammonium, carboxyl, and sulfonyl groups.

[0073] Then, refer to Figure 1 An embodiment of the lithium-ion battery and its materials (electrolyte, binder, buffer, etc.) of the present invention will be described. Figure 1 This is a schematic cross-sectional view illustrating one embodiment of the lithium-ion battery of the present invention.

[0074] The electrolyte composition of the present invention is an electrolyte composition for lithium-ion batteries, comprising the multiblock copolymer of the present invention described above.

[0075] The adhesive composition of the present invention is an adhesive composition for lithium-ion batteries, comprising the multiblock copolymer of the present invention described above.

[0076] The buffer composition of the present invention is a buffer composition for lithium-ion batteries, comprising the multiblock copolymer of the present invention described above.

[0077] Electrolyte compositions, adhesive compositions, and cushioning compositions may contain known ingredients suitable for their respective applications.

[0078] The lithium-ion battery of the present invention comprises at least one of the above-described electrolyte composition, binder composition, and buffer composition.

[0079] The electrolyte composition, adhesive composition, and buffer composition of the present invention comprise the multiblock copolymers of the present invention. Therefore, these compositions can be used in lithium-ion batteries. For example, the electrolyte composition, adhesive composition, and buffer composition of the present invention exhibit excellent adhesion, safety, and stability. Furthermore, for example, lithium-ion batteries using the electrolyte composition of the present invention as a solid electrolyte exhibit conductivity comparable to that of liquid electrolytes, and are safe and stable.

[0080] <One approach to lithium-ion batteries>

[0081] In one embodiment of the lithium-ion battery (lithium-ion secondary battery) of the present invention, the electrolyte can be a composition for an electrolyte containing the multiblock copolymer of the present invention.

[0082] Furthermore, the lithium-ion battery 100 includes a solid electrolyte layer 11, a positive electrode active material layer 12, a negative electrode active material layer 13, a positive electrode current collector 14, and a negative electrode current collector 15. The lithium-ion battery 100 may contain at least one of the electrolyte composition, the binder composition, and the buffer composition of the present invention in at least any one of the solid electrolyte layer 11, the positive electrode active material layer 12, and the positive electrode active material layer 13.

[0083] The lithium-ion battery of the present invention has conductivity comparable to that of liquid electrolytes, excellent adhesion between inorganic electrolytes and electrodes, and excellent safety and stability.

[0084] (Solid electrolyte layer)

[0085] The solid electrolyte layer 11 is formed between the positive electrode active material layer 12 and the negative electrode active material layer 13. The solid electrolyte layer 11 may contain an electrolyte composition comprising the multiblock copolymer of the present invention as a component of the solid electrolyte. The solid electrolyte may also contain solid electrolytes other than the multiblock copolymer of the present invention. Specifically, other solid electrolytes include, for example, lithium aluminum titanium phosphate oxide (LATP), lithium aluminum germanium phosphate oxide (LAGP), and lithium lanthanum zirconium oxide (LLZ). These solid electrolytes may be used alone or in combination of two or more, and may also be used in combination with the multiblock copolymer of the present invention.

[0086] The solid electrolyte layer 11 may also contain an adhesive. The adhesive may also be composed of an adhesive composition comprising the multi-block copolymer of the present invention. Furthermore, the adhesive composition may also use thermoplastic resins, thermosetting resins, etc. Specifically, examples include polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene-butadiene rubber, tetrafluoroethylene-hexafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-trifluorochloroethylene copolymer, ethylene-tetrafluoroethylene copolymer (ETFE resin), polytrifluorochloroethylene (PCTFE), vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-trifluorochloroethylene copolymer (ECTFE), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, ethylene-acrylic acid copolymer, polyacrylic acid, sodium polyacrylate, lithium polyacrylate, polymethacrylic acid, sodium polymethacrylate, lithium polymethacrylate, etc. These adhesives can be used alone or in combination of two or more.

[0087] (Positive electrode active material layer)

[0088] A positive electrode active material layer 12 is formed on the positive electrode current collector 14. The positive electrode active material layer 12 includes a solid electrolyte, an electrode active material, and a conductive material. Additionally, the positive electrode active material layer 12 may also contain various adhesives, such as the adhesive composition of the present invention. The positive electrode active material layer 12 will be described below.

[0089] (Solid electrolyte)

[0090] The electrolyte composition of the present invention can be used as the solid electrolyte contained in the positive electrode active material layer 12. That is, the solid electrolyte may contain the multiblock copolymer of the present invention, or it may contain a solid electrolyte other than the multiblock copolymer of the present invention. Examples of solid electrolytes other than the multiblock copolymer of the present invention include lithium aluminum titanium phosphate oxide (LATP), lithium aluminum germanium phosphate oxide (LAGP), and lithium lanthanum zirconium oxide (LLZ). Solid electrolytes other than the polymers for polymer electrolytes of the present invention may be used alone or in combination with two or more, or they may be combined with the multiblock copolymer of the present invention.

[0091] (Positive electrode active material)

[0092] The electrode active material used in the positive electrode (positive electrode active material) is capable of reversibly releasing / retaining lithium ions. It is not particularly limited to any material capable of electron transport. Examples of positive electrode active materials include lithium transition metal oxides such as lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, and lithium iron phosphate oxide, as well as sulfur and sulfur-based active materials such as lithium sulfide and lithium polysulfides as their discharge products. The positive electrode active material can be composed of one or more of the above materials.

[0093] (Positive conductive material)

[0094] The positive electrode conductive material can use conductive additives commonly used in lithium-ion secondary batteries and all-solid-state lithium-ion secondary batteries. Examples of positive electrode conductive materials include, for instance, carbon blacks such as acetylene black and Ketjen black; carbon fibers; fumed carbon fibers; graphite powder; carbon nanotubes; activated carbon, and other carbon materials. The conductive material can be composed of one or more of these materials.

[0095] (Negative electrode active material layer)

[0096] A negative electrode active material layer 13 is formed on the negative electrode current collector 15. The negative electrode active material layer 13 includes a solid electrolyte, a negative electrode active material, and a negative electrode conductive material. Additionally, the negative electrode active material layer 13 may also contain various adhesives, such as the adhesive composition of the present invention. The negative electrode active material layer 13 will be described below.

[0097] (Solid electrolyte)

[0098] The electrolyte composition of the present invention can be used as the solid electrolyte contained in the negative electrode active material layer 13. That is, the solid electrolyte may contain the multiblock copolymer of the present invention, or it may contain a solid electrolyte other than the multiblock copolymer (electrolyte composition) of the present invention. Examples of solid electrolytes other than the polymer for electrolytes of the present invention include lithium aluminum titanium phosphate oxide (LATP), lithium aluminum germanium phosphate oxide (LAGP), and lithium lanthanum zirconium oxide (LLZ). Solid electrolytes other than the multiblock copolymer (electrolyte composition) of the present invention may be used alone or in combination with two or more, or they may be combined with the multiblock copolymer of the present invention.

[0099] (Negative electrode active material)

[0100] As a negative electrode active material, any material capable of reversibly releasing / retaining lithium ions and enabling electron transport is acceptable; there are no particular limitations. Examples of negative electrode active materials include, for instance, carbonaceous materials such as natural graphite, artificial graphite, resin carbon, carbon fiber, activated carbon, hard carbon, and soft carbon; alloy materials primarily composed of tin, tin alloys, silicon, silicon alloys, gallium, gallium alloys, indium, indium alloys, aluminum, and aluminum alloys; conductive polymers such as polyacene, polyacetylene, and polypyrrole; and lithium metal: lithium-titanium composite oxides, etc. The negative electrode active material can be composed of one or more of the above materials.

[0101] (Negative electrode conductive material)

[0102] The negative electrode conductive material can use conductive additives commonly used in lithium-ion secondary batteries and all-solid-state lithium-ion secondary batteries. Examples of negative electrode conductive materials include, for instance, carbon blacks such as acetylene black and Ketjen black; carbon fibers; fumed carbon fibers; graphite powder; carbon nanotubes; activated carbon, and other carbon materials. The conductive material can be composed of one or more of these materials.

[0103] (Positive current collector)

[0104] The positive current collector 14 is positioned to contact the positive active material layer 12. Due to the presence of the positive current collector 14, it is easy to obtain electricity from the positive active material layer 12. Known positive current collectors can be used as the positive current collector 14, for example, Al, SUS (Steel Use Stainless), etc. Furthermore, the thickness and shape of the positive current collector 14 can be appropriately selected.

[0105] (Negative current collector)

[0106] The negative electrode current collector 15 is positioned to contact the negative electrode active material layer 13. Due to the presence of the negative electrode current collector 15, it is easy to obtain electricity from the negative electrode active material layer 13. Known negative electrode current collectors can be used as the negative electrode current collector 15; for example, Cu can be used. It should be noted that if the electron conductivity of the negative electrode active material layer 13 is high, the negative electrode current collector 15 may not be necessary. Furthermore, the thickness and shape of the negative electrode current collector 15 can be appropriately selected.

[0107] The lithium-ion battery 100 can be manufactured using known methods.

[0108] In addition, without departing from the spirit of the present invention, the constituent elements in the above embodiments can be appropriately replaced with known constituent elements, and the above variations can also be appropriately combined. Specifically, for example, a lithium-ion battery may include a buffer layer. The buffer composition of the present invention can be used in the above-mentioned buffer layer.

[0109] It should be noted that, in the above embodiment, a positive current collector 14 is provided, but if the electron conductivity of the positive active material layer 12 is high, the positive current collector 14 may not be provided. Furthermore, in the above embodiment, a negative current collector 15 is provided, but if the electron conductivity of the negative active material layer 13 is high, the negative current collector 15 may not be provided.

[0110] Next, an embodiment of the method for manufacturing the multiblock copolymer of the present invention will be described.

[0111] In a first embodiment of the method for manufacturing the multiblock copolymer of the present invention, the following steps are included: The process of reacting PEG with isocyanate groups at both ends with poly(PEEGE) to synthesize a compound represented by the following chemical formula (1) (PEEGE-PEG); and The process of synthesizing a multiblock copolymer (PGLYD-PEG) represented by the following chemical formula (2) by reacting an acid with the compound (PEEGE-PEG),

[0112] (In the formula, l is a natural number greater than 2)

[0113] (In the formula, l is a natural number greater than 2).

[0114] For example, PEEGE is synthesized from a difunctional alcohol, and PEG can be a commercially available compound with hydroxyl groups at both ends. By reacting PEG with a diisocyanate compound and then linking it to PEEGE, a compound represented by chemical formula (1) (PEEGE-PEG) can be synthesized. Examples of diisocyanate compounds include, for example, diphenylmethane diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, etc.

[0115] By applying an acid to the compound (PEEGE-PEG) to remove the protection of the hydroxymethyl group, a multi-block copolymer (PGLYD-PEG) represented by the above chemical formula (2) is synthesized. The acid is not particularly limited, and examples include hydrogen chloride gas, hydrochloric acid, and hydrochloric acid methanol solution.

[0116] Furthermore, in the manufacturing method of the present invention, lithium-ion conductivity can be improved by converting a portion of the hydroxyl groups of PGLYD into nitrile groups, thereby increasing the polarity of the polymer. Additionally, residual hydroxyl groups can be converted into an imidazolium salt having a bis(trifluorosulfonyl)imide anion and doped with lithium perchlorate, thereby imparting high lithium-ion conductivity.

[0117] Furthermore, in a second embodiment of the method for manufacturing the multiblock copolymer of the present invention, the following steps are included: The process of reacting PEG, poly-EEGE (PEEGE), and diisocyanate compounds with hydroxyl groups at both ends to synthesize a compound represented by the following chemical formula (1) (PEEGE-PEG); and The process of synthesizing a multiblock copolymer (PGLYD-PEG) represented by the following chemical formula (2) by reacting an acid with the compound (PEEGE-PEG),

[0118] (In the formula, l is a natural number greater than 2)

[0119] (In the formula, l is a natural number greater than 2).

[0120] Specifically, in the second approach, poly(PEEGE) synthesized from a difunctional alcohol and possessing hydroxyl groups at both ends is mixed with PEG, which also possesses hydroxyl groups at both ends, and then linked in a one-step manner using a diisocyanate compound. Therefore, compared to the first approach, the second approach using PEG with hydroxyl groups at both ends is a more direct and simpler method. For example, reacting a solution of PEEGE and PEG with hydroxyl groups at both ends with a diisocyanate compound such as 1,3-bis(isocyanomethyl)cyclohexane can synthesize the compound (PEEGE-PEG).

[0121] As a diisocyanate compound, for example, one or more can be selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates and aromatic diisocyanates.

[0122] Examples of aliphatic diisocyanates include butane diisocyanate, pentane diisocyanate, hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate, and lysine diisocyanate.

[0123] Examples of alicyclic diisocyanates include isophorone diisocyanate (IPDI), hydrogenated phenyl dimethyl diisocyanate, hydrogenated diphenylmethane diisocyanate, and 1,4-cyclohexane diisocyanate.

[0124] Examples of aromatic diisocyanates include phenyl dimethyl diisocyanate (XDI), diphenylmethane diisocyanate (MDI), and toluene diisocyanate (TDI).

[0125] In addition to the steps described above, the method for manufacturing the multiblock copolymer of the present invention may also include a step of synthesizing EEGE (protection of the hydroxymethyl group of glycidyl ester), a step of synthesizing PEEGE, a step of replacing the terminal functional groups of PEG, etc.

[0126] Furthermore, the method for manufacturing the multiblock copolymer of the present invention may also include a step of replacing a portion of the functional groups.

[0127] The following examples illustrate the multiblock copolymers and their manufacturing methods, as well as lithium-ion batteries, of the present invention in more detail. Of course, the present invention is not limited to these examples, and various forms are conceivable.

[0128] Example

[0129] <1> Method for manufacturing multiblock copolymers (first scheme)

[0130] 1) Synthesis of PEG polymers with isocyanate groups at both ends

[0131] PEG (weight average molecular weight 16000, 10 g, OH group 2.5 mmol) with two terminal hydroxyl groups and dibutyltin dilaurate (molecular weight 631.57, 7.89 mg, 0.0125 mmol) were dissolved in 20 mL of toluene. Hexamethylene diisocyanate (molecular weight 168.2, 0.421 g, 2.5 mmol) was added, and the mixture was allowed to react at room temperature overnight. The resulting solution was then transferred to cold diethyl ether, and the precipitated white solid was separated by filtration. The solid was dried under reduced pressure at 50 °C overnight to obtain the target compound (yield 85%).

[0132] 2) Protection of the hydroxymethyl group of glycidol (synthesis of EEGE)

[0133] Ethyl vinyl ether (147 g, 2.04 mol) and glycidyl ether (50 g, 0.675 mol) were added to a three-necked flask equipped with a stirrer, and the mixture was stirred while cooling in a methanol bath. After the solution had cooled sufficiently, 1.25 g (7.26 mmol) of p-toluenesulfonic acid was added in small increments, and the mixture was stirred for 3 hours. A 1 L saturated NaHCO3 aqueous solution was prepared and added to a 170 mL three-necked flask and stirred. The organic layer was then separated using a separatory funnel and washed with the saturated NaHCO3 aqueous solution. MgSO4 was added, and the mixture was stirred overnight and dried. After drying, the MgSO4 was removed by filtration, the product was concentrated using an evaporator, and then purified by vacuum distillation to obtain the final product.

[0134] 3) Synthesis of poly-EEGE

[0135] Tetraethylene glycol (molecular weight 194.23, 1.94 mg, 0.001 mmol), cesium hydroxide (molecular weight 149.912, 0.12 mg, 0.01 mmol), and toluene (30 mL) were added to a two-necked flask. Dehydration was performed using a Dean-Stark reflux tube to prepare cesium salts. The solution was heated to 90 °C, and EEGE (0.146 g, 1 mmol) was added dropwise to induce polymerization. The polymer was precipitated by adding the polymerization solution to hexane. The precipitate was dried overnight at 50 °C to obtain the target compound (polyEEGE:PEEGE) (yield 68%).

[0136] 4) Synthesis of PGLYD-PEG multiblock copolymer

[0137] (In the formula, l is a natural number greater than 2)

[0138] The obtained PEG (weight average molecular weight 8000, 1 g, isocyanate group 0.25 mmol) and PEEGE (weight average molecular weight 14600, 1.825 g, hydroxyl group 0.25 mmol) with isocyanate groups at both ends were added to a flask and stirred with 5 mL of N-methylpyrrolidone (NMP). Dibutyltin dilaurate (molecular weight 631.57, 7.89 mg, 0.0125 mmol) was added as a catalyst, and the mixture was stirred at 60 °C overnight. The resulting polymerization solution was then added to cold diethyl ether, the precipitate was recovered, and the solution was dried at 50 °C overnight to obtain the multiblock copolymer (PEEGE-PEG).

[0139] The generated multiblock copolymer (PEEGE-PEG) was dissolved in THF, and hydrogen chloride gas was blown into it for 10 minutes. Then, nitrogen was blown in, and the solution was put into hexane to recover the precipitated polymer (multiblock copolymer (PGLYD-PEG)).

[0140] 5) Nitrile formation of OH groups in polymers, etc.

[0141] The obtained PGLYD-PEG multiblock copolymer was dissolved in NMP, and sodium hydride was added. Then, 80% of bromopropionitrile (equivalent to the hydroxyl group) was added, and the mixture was dried at 60°C overnight. The solution was then added to acetone to recover the precipitate.

[0142] Excess p-toluenesulfonyl chloride was added to the above-mentioned nitrified PGLYD-PEG multiblock copolymer to activate the hydroxyl groups, and ethyl imidazole was added to convert the hydroxyl groups to imidazole onium salts. Then, lithium bis(trifluorosulfonyl)imide was added to replace the chloride ions with bis(trifluorosulfonyl)imide.

[0143] 6) The PGLYD-PEG multiblock copolymer obtained above exhibits sufficient adhesion to aluminum foil. Furthermore, the multiblock copolymer shows good solubility in NMP and water. The lithium-ion conductivity is 10 at room temperature. -5 S / m shows a good value as an adhesive.

[0144] <2> Manufacturing method (second scheme) and characteristics of multiblock copolymers

[0145] (1) Equipment Analysis

[0146] NMR spectrum: 1 H-NMR, 13 C-NMR, DEPT-135, and two-dimensional NMR spectra were performed using a JNM-ECA500 (JEOL). Tetramethylsilane (TMS) was used as the internal standard, and CDCl3 and DMSO-d6 were used as deuterated solvents.

[0147] IR spectroscopy: Using an FT-IR 4200 type A (JASCO), with KBr as the reference material, trace amounts of the compound were added to KBr, and measurements were performed by light transmittance method. The prepared gel or membrane was measured by total reflectance method (ATR method).

[0148] Molecular weight determination: 15 mg of sample was dissolved in 5 mL of THF or NMP, and the weight-average molecular weight (Mw), number-average molecular weight (Mn), and dispersity (Mw / Mn) were determined using a high-speed GPC system HLC-8420 (Tosoh Corporation) and a dissolution curve converted from polystyrene.

[0149] Solubility test: 10 mg of the sample was added to 5 mL of various solvents, stirred for 24 hours, and then the solubility was confirmed. For undissolved samples, the temperature was raised to near the boiling point, stirred for another 24 hours, and then allowed to stand at room temperature to confirm whether precipitation was observed. Commercially available solvents were used directly without purification. The solvents used are shown below.

[0150] Chloroform (CHCl3) N-Methylpyrrolidone (NMP) Tetrahydrofuran (THF) Methanol (MeOH) Toluene hexane acetone Water (H2O) (2) Synthesis of EEGE (2,3-Epoxypropyl-1-ethoxyethyl ether). (operate) Add ethyl vinyl ether (196 ml, 2.04 mol) and glycidyl ether (44.6 ml, 0.675 mol) to a 300 ml single-necked flask equipped with a stirrer. While cooling in a cryogenic bath set to -25°C, stir under nitrogen. After the solution has cooled sufficiently, add TsOH in small, incremental amounts. After adding H2O (1.38g, 7.26mmol), stir for 3 hours.

[0151] (deal with)

[0152] The solution was transferred to a separatory funnel and washed with 1 L of pre-prepared saturated NaHCO3 aqueous solution. The pH was measured to be 7, confirming the removal of TsOH. MgSO4 was then added and the mixture was stirred overnight for dehydration.

[0153] (purification)

[0154] After dehydration, MgSO4 was removed by filtration, the product was concentrated using an evaporator, and then purified by vacuum distillation (diaphragm, 110℃) to obtain the product.

[0155] (result)

[0156] Appearance: Colorless and transparent liquid.

[0157] Yield: 47.0g.

[0158] Yield: 47.6%.

[0159]

[0160] Figure 2 It shows the product. 1 The 1H NMR spectrum (400MHz, CDCl3) is shown in the figure. Figure 2 As shown, EEGE was confirmed to have been synthesized as a product.

[0161] (3) Synthesis of PEEGE

[0162] (operate)

[0163] Tetraethylene glycol (0.074 g, 0.38 mmol) and cesium hydroxide monohydrate (0.13 g, 0.70 mmol) were added to a 50 ml single-necked flask equipped with a stir bar, a Dean-Stark water separator, a thermometer, a cooling tube, and a three-way stopcock. The mixture was reacted overnight at 130 °C in toluene (20 ml) under nitrogen. After the reaction, the Dean-Stark water separator was removed, and toluene was removed by vacuum distillation (40 °C), followed by vacuum distillation at 100 °C for 1 hour to completely remove toluene. Then, the cooling tube was installed, and EEGE (4.4 g, 30 mmol) was added under nitrogen, and the mixture was reacted at 65 °C for 2 days.

[0164] (deal with)

[0165] To stop the polymerization, use methanol / acetic acid (1:1).

[0166] (purification)

[0167] Dissolved in tetrahydrofuran, then added to water and dried under reduced pressure at 100°C. The resulting product was analyzed by IR spectroscopy. 1 Its structure was analyzed by H NMR and GPC.

[0168] (result)

[0169] Properties: Viscous liquid.

[0170] Yield: 4.49g.

[0171] Yield: 94.5%.

[0172] GPC data.

[0173] Mn = 3900.

[0174] Mw = 4800.

[0175] Mw / Mn = 1.24.

[0176]

[0177] Figure 3 The image shows the FT-IR spectrum of the product. Figure 4 (a) shows the product solution. 1 The 1H NMR spectrum, Figure 4 (b) shows the product obtained. 1 The 1H NMR spectrum. (See figure) Figure 3 and Figure 4 As shown, PEEGE was confirmed to have been synthesized as a product.

[0178] (4) Synthesis of multiblock copolymer (PEG-PEEGE)

[0179] (operate)

[0180] Following the same procedure as in the synthesis of PEEGE, tetraethylene glycol (0.074 g, 0.38 mmol) and cesium hydroxide monohydrate (0.13 g, 0.70 mmol) were added to a 50 mL single-necked flask equipped with a stir bar, a Dean-Stark tube, a thermometer, a cooling tube, and a three-way stopcock. The mixture was reacted overnight at 130 °C in a nitrogen atmosphere in 20 mL of toluene. After the reaction, the Dean-Stark apparatus was removed, and toluene was removed by vacuum distillation (40 °C), followed by vacuum distillation at 100 °C for 1 hour to completely remove toluene. Then, a cooling tube was installed, and under a nitrogen environment, EEGE (4.4 g, 30 mmol) was added and reacted at 65 °C for 2 days to prepare the cesium (Cs) salt of PEEGE. After returning to room temperature, PEG3k (2.0 g, 0.55 mmol) and hexamethylene diisocyanate (0.16 g, 0.98 mmol) dissolved in NMP solvent (1 mL) were added, and dibutyltin dilaurate (0.019 g, 0.03 mmol) was added. The mixture was reacted at 60 °C overnight.

[0181] (deal with)

[0182] It was poured into a silicon mold while heated.

[0183] (purification)

[0184] To prevent the silicon mold from cooling, it was placed in a vacuum oven pre-set at 50°C and dried under reduced pressure at 140°C. The resulting product was then analyzed using IR spectroscopy. 1 Its structure was analyzed by H NMR and GPC.

[0185] (result)

[0186] Shape: Viscous liquid.

[0187] Yield: 2.84g.

[0188] Yield: 42.4%.

[0189] Mn = 6500.

[0190] Mw = 14000.

[0191] Mw / Mn = 2.2.

[0192]

[0193] Figure 5 The FT-IR spectrum of PEG-PEEGE is shown. Figure 6 It shows PEG, PEEGE, and PEG-PEEGE. 1The 1H NMR spectrum. (See figure.) Figure 5 and Figure 6 As shown, the synthesis of a multiblock copolymer of PEG-PEEGE as a product was confirmed.

[0194] (5) Synthesis (deprotection) of multiblock copolymer (PEG-PGLYD)

[0195] (operate)

[0196] Add PEG-PEEGE (1.36 g, 0.21 mmol) and chloroform solvent (40 mL) to a 100 mL two-necked flask equipped with a stir bar, and stir at room temperature until dissolved. Add concentrated sulfuric acid (10 mL, 0.184 mol) to a dropping funnel with a side tube, and add excess NaCl (15 g, 0.26 mol) to a 200 mL two-necked flask equipped with a stir bar, connecting it to the dropping funnel. Install a three-way stopcock on the other neck of the flask containing NaCl, and assemble the apparatus in the following order: anti-backflow Erlenmeyer flask, reaction vessel equipped with a Pasteur tube, and bottle containing NaOH aqueous solution. Then, slowly add concentrated sulfuric acid dropwise to generate HCl gas from the reaction solution.

[0197] (deal with)

[0198] Nitrogen is blown into the reaction solution to remove HCl.

[0199] (purification)

[0200] After removing chloroform using an evaporator, IR is used... 1 The structure of the obtained product was analyzed by 1H NMR.

[0201] (result)

[0202] Properties: Viscous liquid.

[0203] Yield: 1.161g.

[0204] Yield: 85.92%.

[0205] Figure 7 The image shows the IR spectra of PEG-PGLYD and PEG-PEEGE. Figure 8 It shows PEG-PEEGE and PEG-PGLYD. 1 The 1H NMR spectrum. (See figure) Figure 7 and Figure 8 As shown, it was confirmed that PEEGE was converted to PGLYD by acid, and a multi-block copolymer of PEG-PGLYD was synthesized.

[0206] Figure 9This is a schematic diagram illustrating one embodiment of the manufacturing method of the multiblock copolymer of the present invention (manufacturing method 2 described above). In this manufacturing method (manufacturing method 2 described above), two PEG and diisocyanate compounds with OH-terminated groups are added to a PEEGE salt. Compared with preparation method 1, there are fewer reaction steps, therefore, the PEG-PGLYD multiblock copolymer can be synthesized easily and at low cost. It should be noted that in Figure 9 Among them, an example of its use as an electrolyte is shown, in which lithium bis(trifluorosulfonyl)imide is added to a multiblock copolymer and bis(trifluorosulfonyl)imide is added at the end.

[0207] <3> Solubility of multiblock copolymers (PEG-PGLYD)

[0208] 1.5 g of the multiblock copolymer synthesized as described above was added to 3 mL of NMP and stirred at room temperature for 24 hours. Figure 10 As shown, the dissolution of the multiblock copolymer into a homogeneous solution was confirmed, indicating that the multiblock copolymer has high solubility.

[0209] <4> The tackiness of multi-block copolymers (PEG-PGLYD) (used in adhesives)

[0210] Using a film forming apparatus, the NMP solution of the multi-block copolymer synthesized by the above method was coated onto a SUS substrate to a thickness of 25 micrometers, and dried at 120°C for 10 minutes. Figure 11 The coating exhibits tackiness when touched with a finger, confirming that it has sufficient adhesion.

[0211] <5> Positive electrode materials for lithium-ion batteries using multi-block copolymers (PEG-PGLYD)

[0212] The NMP solution of the multi-block copolymer synthesized as described above was mixed with ferric phosphate containing conductive material and coated onto aluminum foil to form a slurry. Then, it was dried at 110°C for 10 minutes and pressed to obtain the positive electrode material. Figure 12 ).like Figure 12 As shown, for the cathode material, no coating peeling was confirmed.

[0213] <6> Charge-discharge tests of lithium-ion batteries using multi-block copolymer (PEG-PGLYD)

[0214] Will Figure 12 The positive electrode material obtained was cut into coin-shaped battery dimensions, and the initial charge-discharge characteristics of the fabricated battery were tested. For example... Figure 13 As shown, it was confirmed that no sharp capacity drop occurred, and it can be used as an electrode adhesive.

[0215] <7> Cycling tests of lithium-ion batteries using multiblock copolymers (PEG-PGLYD)

[0216] Will Figure 12 The positive electrode material obtained was cut into coin-shaped battery dimensions, and cycle tests were conducted on the manufactured batteries. For example... Figure 14 As shown, no sharp performance degradation was observed in the cycle tests up to 10 times, confirming that it can function normally as a secondary battery.

[0217] Explanation of reference numerals in the attached figures

[0218] 100: Lithium-ion battery.

[0219] 11: Solid electrolyte layer.

[0220] 12: Positive electrode active material layer.

[0221] 13: Negative electrode active material layer.

[0222] 14: Positive current collector.

[0223] 15: Negative current collector.

Claims

1. A multiblock copolymer, wherein, The connection consists of two or more unit structures, which are formed by bonding soft segments of polyglycidyl PGLYD with hard segments of polyethylene glycol PEG.

2. The multiblock copolymer of claim 1, wherein, The weight-average molecular weight of the multiblock copolymer is above 10,000.

3. The multiblock copolymer of claim 1, wherein, The multiblock copolymer has lithium-ion conduction pathway groups.

4. An electrolyte composition, which is an electrolyte composition for lithium-ion batteries, wherein, The electrolyte composition comprises the multiblock copolymer of claim 1.

5. An adhesive composition for use in lithium-ion batteries, wherein, The adhesive composition comprises the multiblock copolymer of claim 1.

6. A buffer composition for use in lithium-ion batteries, wherein, The buffer composition comprises the multiblock copolymer of claim 1.

7. A lithium-ion battery, wherein, The lithium-ion battery comprises at least one of the electrolyte composition of claim 4, the adhesive composition of claim 5, and the buffer composition of claim 6.

8. A method for manufacturing a multiblock copolymer, which is the method for manufacturing the multiblock copolymer according to claim 1, wherein, The method for manufacturing the multiblock copolymer includes the following steps: The process of reacting polyethylene glycol (PEG) with isocyanate groups at both ends with poly(2,3-epoxypropyl-1-ethoxyethyl ether), i.e., PEEGE, to synthesize a compound represented by the following chemical formula (1); and The process of reacting an acid with the compound to synthesize a multiblock copolymer represented by the following chemical formula (2), In equation (1), l is a natural number greater than 2. In equation (2), l is a natural number greater than 2.

9. A method for manufacturing a multiblock copolymer, comprising the method for manufacturing a multiblock copolymer as described in claim 1, wherein, The method for manufacturing the multiblock copolymer includes: The process of reacting polyethylene glycol (PEG), poly(2,3-epoxypropyl-1-ethoxyethyl ether), i.e. PEEGE, and a diisocyanate compound with hydroxyl groups at both ends to synthesize a compound represented by the following chemical formula (1); and The process of reacting an acid with the compound to synthesize a multiblock copolymer represented by the following chemical formula (2), In equation (1), l is a natural number greater than 2. In equation (2), l is a natural number greater than 2.

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