JP5179884B2 - Non-aqueous electrolyte and lithium ion secondary battery provided with the same - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte and a lithium ion secondary battery including the same.

Conventionally, as a non-aqueous electrolyte used in a lithium ion secondary battery, by adding a silicon compound having an unsaturated bond to the electrolyte, the rate of change in electric capacity and internal resistance is small during repeated charging and discharging, and The thing which was excellent in the cycle characteristic and low temperature characteristic that an internal resistance increase at the time of low temperature is small and maintains a high electrical capacitance is proposed (for example, refer patent document 1).
JP 2002-134169 A

  However, the non-aqueous electrolyte described in Patent Document 1 is excellent in cycle characteristics and low-temperature characteristics by adding a silicon compound, but is still insufficient and has higher cycle characteristics and low-temperature characteristics. Things were desired.

  The present invention has been made in view of the above problems, and further improves the cycle characteristics in repeated charge and discharge, and further improves the low temperature characteristics, and a lithium ion solution using the same. An object is to provide a secondary battery.

  As a result of diligent research in order to achieve the above-described object, the present inventors found that a non-aqueous electrolyte used for a lithium ion secondary battery was obtained by combining lithium bisoxalatoborate and divinyltetraalkyldisiloxane (carbon number of alkyl). And 1 to 4), it has been found that the cycle characteristics in repeated charge and discharge can be further improved, and the low temperature characteristics can be further improved, and the present invention has been completed.

That is, the non-aqueous electrolyte of the present invention is
A non-aqueous electrolyte used in a lithium ion secondary battery,
An electrolyte salt containing lithium, 0.05% by weight or more of lithium bisoxalatoborate, and 0.05% by weight or more of divinyltetraalkyldisiloxane (wherein the alkyl has 1 to 4 carbon atoms).

The lithium ion secondary battery of the present invention is
A positive electrode having a positive electrode active material;
A negative electrode having a negative electrode active material;
The non-aqueous electrolyte described above that is interposed between the positive electrode and the negative electrode and conducts lithium ions;
It is equipped with.

  In the non-aqueous electrolyte and the lithium ion secondary battery including the non-aqueous electrolyte, it is possible to further improve cycle characteristics in repeated charge / discharge and further improve low-temperature characteristics. The reason why such an effect is obtained is not clear, but is presumed as follows. For example, lithium bisoxalatoborate forms a film on the surface of the negative electrode active material at the time of charging, and suppresses the deactivation of lithium ions on the surface of the negative electrode active material associated with the charge / discharge cycle when it is contained by 0.05 wt% or more It is presumed that a decrease in battery capacity can be suppressed. In addition, divinyltetraalkyldisiloxane is a compound that has an unsaturated bond and is easily self-polymerized, and forms a stable film by polymerization reaction on the electrode surface during charge and discharge, and contains 0.05% by weight or more. It is presumed that the increase in resistance at the electrode / electrolyte interface accompanying the charge / discharge cycle can be suppressed. It is presumed that the effect of each compound is exhibited synergistically.

  A lithium ion secondary battery of the present invention includes a positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material, and a non-aqueous electrolyte that is interposed between the positive electrode and the negative electrode and conducts lithium ions. . This non-aqueous electrolyte includes an electrolyte salt containing lithium, 0.05% by weight or more of lithium bisoxalatoborate, 0.05% by weight or more of divinyltetraalkyldisiloxane (the alkyl has 1 to 4 carbon atoms) ).

The positive electrode of the lithium ion secondary battery of the present invention is prepared by mixing a positive electrode active material, a conductive material, and a binder, and adding a suitable solvent to form a paste-like positive electrode material on the surface of the current collector. It may be formed by coating and drying, and compressing to increase the electrode density as necessary. As the positive electrode active material, a sulfide containing a transition metal element, an oxide containing lithium and a transition metal element, or the like can be used. Specifically, transition metal sulfides such as TiS ₂ , TiS ₃ , MoS ₃ , FeS ₂ , Li _x MnO ₂ (0.5 ≦ x ≦ 1.5, etc.), Li _x Mn ₂ O _4, etc. Lithium manganese composite oxide, lithium cobalt composite oxide such as Li _x CoO ₂ , lithium nickel composite oxide such as Li _x NiO ₂ , lithium vanadium composite oxide such as LiV ₂ O ₃ , transition such as V ₂ O ₅ A metal oxide or the like can be used. Of these, lithium transition metal composite oxides are preferred. The conductive material is for ensuring the electrical conductivity of the positive electrode. For example, one or two kinds of graphite such as natural graphite and artificial graphite, carbon black such as acetylene black, and amorphous carbon such as needle coke are used. What mixed the above can be used. The binder plays a role of connecting the active material particles and the conductive material particles. For example, the binder is a fluorine-containing resin such as polytetrafluoroethylene, polyvinylidene fluoride, or fluororubber, or a thermoplastic resin such as polypropylene or polyethylene. Etc. can be used. In addition, an aqueous dispersion of a cellulose-based or styrene-butadiene rubber that is an aqueous binder can also be used. Examples of the solvent for dispersing the positive electrode active material, the conductive material, and the binder include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, and N, N-dimethylaminopropyl. Organic solvents such as amine, ethylene oxide, and tetrahydrofuran can be used. As the current collector, foil of aluminum, stainless steel, nickel plated steel, or the like can be used.

  The negative electrode of the lithium ion secondary battery of the present invention is prepared by mixing a negative electrode active material, a conductive material, and a binder, and adding a suitable solvent to form a paste-like negative electrode material on the surface of the current collector. It may be formed by coating and drying, and compressing to increase the electrode density as necessary. Examples of negative electrode active materials include inorganic compounds such as lithium, lithium alloys and tin compounds, carbonaceous materials capable of occluding and releasing lithium ions, and conductive polymers. Among these, carbonaceous materials are used from the viewpoint of safety. It is preferable to see. The carbonaceous material is not particularly limited, but graphite, petroleum-based coke, coal-based coke, petroleum-based pitch carbide, coal-based pitch carbide, phenolic resin, crystalline cellulose cellulose resin, and the like. Examples include carbonized carbon, furnace black, acetylene black, pitch-based carbon fiber, and PAN-based carbon fiber. In addition, as the conductive material, binder, solvent, and the like used for the negative electrode, those exemplified for the positive electrode can be used. For the current collector of the negative electrode, a foil such as copper, nickel, stainless steel, or nickel-plated steel can be used.

  The lithium ion secondary battery of the present invention may include a separator between the negative electrode and the positive electrode. The separator is not particularly limited as long as it is a material that can withstand the use range of the secondary battery, such as a microporous film of a polymer compound. For example, polyethers such as polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, polyethylene oxide, carboxymethylcellulose and hydroxypropyl Examples thereof include celluloses such as cellulose, polymer compounds mainly composed of poly (meth) acrylic acid and other esters and derivatives thereof, and films made of copolymers or mixtures thereof. These may be used alone or in combination. Further, for example, an additive for enhancing ion conductivity and various additives for enhancing strength and corrosion resistance may be added to these films. Of these microporous films, polyethylene, polypropylene, polyvinylidene fluoride, polysulfone and the like are preferably used. This separator is preferably microporous so that the non-aqueous electrolyte can penetrate and ions can easily pass therethrough. This microporosification method includes the “phase separation method” in which a film of the above polymer compound and a solvent is formed while microphase separation is performed, and the solvent is extracted and removed to make it porous. There is a “stretching method” in which a film is formed by extrusion and then heat-treated to arrange crystals in one direction, and a gap is formed between the crystals by stretching to make it porous.

  The non-aqueous electrolyte of the lithium ion secondary battery of the present invention contains 0.05% by weight or more of lithium bisoxalatoborate. The lithium bisoxalatoborate content is more preferably 0.1 wt% or more and 10 wt% or less, and still more preferably 0.2 wt% or more and 5 wt% or less. If this content is 0.05% by weight, a decrease in battery capacity upon repeated charge / discharge can be sufficiently suppressed, and if it is 10% by weight or less, the content of lithium bisoxalatoborate can be further suppressed. Thus, an increase in resistance due to the film formed on the electrode can be suppressed. When the content is 0.2 wt% or more and 5 wt% or less, the above effect can be obtained. Here, the content of lithium bisoxalatoborate is 100% by weight of a mixed solution of an organic solvent and divinyltetraalkyldisiloxane, and the addition ratio (% by weight) with respect to 100% by weight. The nonaqueous electrolytic solution contains 0.05% by weight or more of divinyltetraalkyldisiloxane (the alkyl has 1 to 4 carbon atoms). The content of the divinyltetraalkyldisiloxane is more preferably 0.1% by weight or more and 10% by weight or less, and further preferably 0.2% by weight or more and 5% by weight or less. If this content is 0.05% by weight, the increase in battery resistance when charging and discharging is repeated can be sufficiently suppressed, and if it is 10% by weight or less, the content of divinyltetraalkyldisiloxane can be further suppressed. Thus, an increase in resistance due to the film formed on the electrode can be suppressed. When the content is 0.2 wt% or more and 5 wt% or less, the above effect can be obtained. The divinyltetraalkyldisiloxane preferably has a smaller alkyl group carbon number, and divinyltetramethyldisiloxane can be suitably used. Here, the content of divinyltetraalkyldisiloxane is 100% by weight of a mixed solution of an organic solvent and lithium bisoxalatoborate, and is a value of the addition ratio (% by weight) with respect to 100% by weight. The lithium bisoxalatoborate and divinyltetraalkyldisiloxane can be used in the above-mentioned addition ranges, respectively, but the total amount of lithium bisoxalatoborate and divinyltetraalkyldisiloxane is 20% by weight or less. It is preferably 12% by weight or less, more preferably 4% by weight or less. From the viewpoint of the relationship between the content and the effect to be obtained and the cost, it is more preferable to add at 0.1 wt% to 2.0 wt%.

  In the non-aqueous electrolyte of the lithium ion secondary battery of the present invention, lithium bisoxalatoborate and divinyltetraalkyldisiloxane are dissolved in an organic solvent. As the organic solvent, carbonates, lactones, ethers, sulfolanes, dioxolanes and the like can be used. Specifically, as carbonates, cyclic carbonates such as ethylene carbonate, propylene carbonate, vinylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl-n-butyl carbonate, methyl-t-butyl carbonate, di-carbonate, -Chain carbonates such as i-propyl carbonate and t-butyl-i-propyl carbonate, etc., lactones such as γ-butyl lactone and γ-valerolactone, dimethoxyethane, ethoxymethoxyethane, diethoxyethane as ethers Examples include sulfolane and sulfomethyl as sulfolanes, and 1,3-dioxolane as dioxolanes. Among these, the combination of cyclic carbonates and chain carbonates is preferable. According to this combination, not only the cycle characteristics representing the battery characteristics in repeated charge and discharge are excellent, but also the viscosity of the electrolyte, the electric capacity of the obtained battery, the battery output, etc. should be balanced. it can. The cyclic carbonates are considered to have a relatively high relative dielectric constant and increase the dielectric constant of the electrolytic solution, and the chain carbonates are considered to suppress the viscosity of the electrolytic solution.

Examples of the electrolyte salt included in the lithium ion secondary battery of the present invention include LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , and LiC (CF ₃ SO ₂ ) _{3. , LiSbF 6, LiSiF 6, LiAlF} 4, LiSCN, LiClO 4, LiCl, LiF, LiBr, LiI, and the like LiAlCl _4. Among these, from the group consisting of inorganic salts such as LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiClO ₄ , and organic salts such as LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) _3. It is preferable from the viewpoint of electrical characteristics to use a combination of one or two or more selected salts. This electrolyte salt preferably has a concentration in the non-aqueous electrolyte of 0.1 mol / L or more and 3.0 mol / L or less, and more preferably 0.5 mol / L or more and 2.0 mol / L or less. When the concentration of the electrolyte salt is 0.1 mol / L or more, a sufficient current density can be obtained, and when the concentration is 3.0 mol / L or less, the electrolytic solution can be more stabilized. Moreover, you may add flame retardants, such as a phosphorus type and a halogen type, to this non-aqueous electrolyte. Specifically, this flame retardant is phosphorous, for example, phosphoric esters such as trimethyl phosphate and triethyl phosphate, melamine polyphosphate and ammonium polyphosphate, polyethylene phosphate ethylenediamine, polyphosphate hexamethylenediamine, Polyphosphoric acids such as polyphosphate piperazine salts can be used. The content of the flame retardant is preferably 5 parts by weight or more and 100 parts by weight or less, and more preferably 10 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the total organic solvent constituting the nonaqueous electrolytic solution. When the content of the flame retardant is 5 parts by weight or more, a sufficient flame retardant effect is obtained, and when the content is 100 parts by weight or less, an increase in resistance of the electrolytic solution can be further suppressed.

  The shape of the lithium ion secondary battery of the present invention is not particularly limited, and examples thereof include a coin type, a button type, a sheet type, a laminated type, a cylindrical type, a flat type, and a square type. Moreover, you may apply to the large sized thing etc. which are used for an electric vehicle etc. FIG. 1 is a schematic view showing an example of a lithium ion secondary battery 10 of the present invention. The lithium ion secondary battery 10 includes a positive electrode sheet 13 in which a positive electrode active material 12 is formed on a current collector 11, a negative electrode sheet 18 in which a negative electrode active material 17 is formed on the surface of the current collector 14, a positive electrode sheet 13 and a negative electrode A separator 19 provided between the sheet 18 and a nonaqueous electrolytic solution 20 that fills between the positive electrode sheet 13 and the negative electrode sheet 18 are provided. In this lithium ion secondary battery 10, a separator 19 is sandwiched between a positive electrode sheet 13 and a negative electrode sheet 18, and these are wound and inserted into a cylindrical case 22, and a positive electrode terminal 24 and a negative electrode sheet connected to the positive electrode sheet 13. And a negative electrode terminal 26 connected to each other. The non-aqueous electrolyte 20 is composed of an electrolyte salt containing lithium in an organic solvent, 0.05 wt% to 10 wt% lithium bisoxalatoborate, and 0.05 wt% to 10 wt% divinyl. And tetramethyldisiloxane.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

  Below, the example which produced the lithium ion secondary battery concretely is demonstrated as an experiment example.

[Production of lithium ion secondary battery]
85% by weight of LiNiO ₂ as a positive electrode active material, 10% by weight of acetylene black as a conductive material, 5% by weight of polyvinylidene fluoride as a binder, and an appropriate amount of N-methyl-2-pyrrolidone as a dispersant are added to form a slurry. A positive electrode material was obtained. This positive electrode material slurry was uniformly applied on both surfaces of a 20 μm thick aluminum foil current collector, and dried by heating to prepare a positive electrode coated sheet. Thereafter, the coated sheet was pressed, cut into a rectangular shape of a predetermined size, and the positive electrode material at a portion to be a lead tab weld for extracting current was peeled off to obtain a sheet-like positive electrode. A negative electrode active material was mixed with 95% by weight of carbon material powder and 5% by weight of polyvinylidene fluoride as a binder, and a negative electrode slurry was prepared in the same manner as the positive electrode. This was uniformly applied to both sides of a 10 μm thick copper foil current collector. And dried by heating to prepare a negative electrode coated sheet. Thereafter, this coated sheet was pressed, cut into a rectangular shape of a predetermined size, and the negative electrode material in a portion to be a lead tab weld for extracting current was peeled off to obtain a sheet-like negative electrode. These positive electrode and negative electrode are wound around a separator made of a microporous polyethylene film having a thickness of 25 μm to form a roll-shaped electrode body, and this roll-shaped electrode body is inserted into a 18650-type cylindrical case. Kept inside. At this time, the current collecting leads connected to the lead tab welds of the positive electrode and the negative electrode were respectively joined to the positive electrode terminal and the negative electrode terminal provided in the case. Thereafter, a non-aqueous electrolyte described later was poured into the case and sealed to obtain a cylindrical lithium ion secondary battery (see FIG. 1). The lithium ion secondary batteries of Experimental Examples 1 to 17 were obtained by changing the content of the nonaqueous electrolyte.

[Experimental Example 1]
As a non-aqueous electrolyte, ethyl carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) were mixed at a volume ratio of 1: 1: 1, and LiPF ₆ was added at 1 mol / L. A lithium ion secondary battery manufactured by using one dissolved at a concentration was set as Experimental Example 1.

[Experimental Examples 2 to 10]
1 part by weight of lithium bisoxalatoborate is added to 99 parts by weight of the mixed solvent used in Experimental Example 1, and 0.0 part by weight, 0.03 part by weight, 0.05 part by weight with respect to 100 parts by weight. 1 part by weight, 0.10 part by weight, 1.0 part by weight, 2.0 parts by weight, 5.0 parts by weight, 10.0 parts by weight, and 15.0 parts by weight of divinyltetramethyldisiloxane The lithium ion secondary batteries produced using these were designated as Experimental Examples 2 to 10, respectively.

[Experimental Examples 11 to 17]
1 part by weight of divinyltetramethyldisiloxane is added to 99 parts by weight of the mixed solvent used in Experimental Example 1 above, and 0.0 part by weight, 0.05 part by weight, 0.10 with respect to 100 parts by weight. Experiments were conducted on lithium ion secondary batteries produced using parts by weight, 2.0 parts by weight, 5.0 parts by weight, 10.0 parts by weight, and 15.0 parts by weight of lithium bisoxalatoborate, respectively. It was set as Examples 11-17.

[Initial discharge capacity]
The lithium ion secondary batteries of Examples 1 to 17 produced, after constant current charging at 0.2 mA / cm ² up to 4.1 V, was constant current discharge to 3.0V at 0.2 mA / cm ² . Then, after charging at 0.2 mA / cm ² up to 4.1 V, a constant current discharge to 3.0V at 0.1 mA / cm ^2, and the discharge capacity at this time as the initial discharge capacity V0. The measurement was performed in an atmosphere at 20 ° C.

[High-temperature cycle characteristics test, discharge capacity maintenance rate]
Put a lithium ion secondary battery of Example 1 to 17 in a thermostat at ambient temperature 60 ° C., and a constant current charging to 4.1V at a discharge current 2.0 mA / cm ^2, at a discharge current of 2.0 mA / cm ² A charge / discharge for performing constant-current discharge up to 3.0 V was taken as one cycle, and a high-temperature cycle characteristic test was performed in which this cycle was performed for a total of 500 cycles. Thereafter the high-temperature cycle characteristics test, the atmospheric temperature 20 ° C., after which a constant current charged at 0.2 mA / cm ² up to 4.1 V, was constant current discharge to 3.0V at 0.2 mA / cm ^2. Then, after charging at 0.2 mA / cm ² up to 4.1 V, a constant current discharge at 0.1 mA / cm ² up to 3.0 V, and the discharge capacity at this time as a cycle after the discharge capacity Vc. Using the discharge capacity Vc after the cycle and the initial discharge capacity V0, the discharge capacity retention ratio Vk (%) was obtained by the following equation (1).
Discharge capacity retention rate Vk (%) = Vc / V0 × 100 (1)

[Battery resistance increase rate]
Using the lithium ion secondary batteries of Experimental Examples 1 to 17, the battery resistance increase rate Rin when the charge / discharge cycle was repeated was determined. The battery resistance was 20 ° C., constant current and constant voltage charge to 3.7 V at a charge current of 0.2 mA / cm ² , then constant current discharge at a discharge current of 10 mA / cm ² , and the voltage after 10 seconds was measured. This value obtained by voltage drop was defined as battery resistance R ₂₀ at 20 ° C. After charging at a constant current and a constant voltage up to 3.7V at a charging current of 0.2 mA / cm ² again at 20 ° C., holding at −30 ° C. for 3 hours, and discharging at a constant current of 10 mA / cm ² again. The voltage after 10 seconds was measured, and the value of the battery resistance obtained by the voltage drop was defined as the battery resistance R- ₃₀ at -30 ° C. The battery resistance increase rate Rin at 20 ° C. is obtained by using the battery resistance Rb measured before the high temperature cycle characteristic test and the battery resistance Ra measured after the high temperature cycle characteristic test at 20 ° C. Determined by In addition, the battery resistance was measured before and after the high temperature cycle characteristic test at −30 ° C., and the battery resistance increase rate Rin at −30 ° C. was also obtained.
Battery resistance increase rate Rin (%) = (Ra−Rb) / Rb × 100 (2)

[Initial resistance characteristics]
Using the lithium ion secondary batteries of Experimental Examples 1 to 17, the initial resistance characteristic Rs was obtained at 20 ° C. and −30 ° C. in the state before the high temperature cycle characteristic test. Here, the initial resistance characteristic Rs is a relative value based on the initial battery resistance Rb1 of Example 1 in which lithium bisoxalatoborate and divinyltetramethyldisiloxane are not added as a reference (= 100). Obtained using.
Initial resistance characteristic Rs = Rb / Rb1 × 100 (3)

[Measurement result]
The measurement results of Experimental Examples 1 to 17 are shown in Table 1, the relationship of the battery resistance increase rate to the content of divinyltetramethyldisiloxane of Experimental Examples 1 to 10 is shown in FIG. 2, and Experimental Examples 1, 6, 11 to 17 are shown. FIG. 3 shows the relationship between the battery resistance increase rate and the lithium bisoxalatoborate content, and FIG. 4 shows the relationship between the discharge capacity retention rate and the initial resistance characteristics with respect to the divinyltetramethyldisiloxane content in Experimental Examples 1 to 10. FIG. 5 shows the relationship between the discharge capacity retention ratio and the initial resistance characteristics with respect to the lithium bisoxalatoborate content of Experimental Examples 1, 6, and 11-17. As a result, when the lithium bisoxalatoborate content is 0.05 wt% to 10 wt%, the cycle characteristics are higher than those not added, and the battery resistance is increased at a low temperature of −30 ° C. It became clear that it could be suppressed. In addition, the content of divinyltetramethyldisiloxane is 0.05 wt% to 10 wt%, which shows higher cycle characteristics than those not added, and suppresses increase in battery resistance at a low temperature of −30 ° C. It became clear that it was possible.

It is a schematic diagram which shows an example of the lithium ion secondary battery 10 of this invention. It is a related figure of the battery resistance increase rate with respect to content of divinyltetramethyldisiloxane. It is a related figure of the battery resistance increase rate with respect to content of lithium bisoxalatoborate. It is a relationship figure of the discharge capacity maintenance factor with respect to content of divinyltetramethyldisiloxane, and an initial stage resistance characteristic. It is a relationship figure of discharge capacity maintenance factor with respect to content of lithium bisoxalatoborate, and initial resistance characteristics.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Lithium ion secondary battery, 11 Current collector, 12 Positive electrode active material, 13 Positive electrode sheet, 14 Current collector, 17 Negative electrode active material, 18 Negative electrode sheet, 19 Separator, 20 Nonaqueous electrolyte, 22 Cylindrical case, 24 Positive electrode Terminal, 26 Negative terminal.

Claims (5)

A non-aqueous electrolyte used in a lithium ion secondary battery,
0 . 1% by weight or more and 10% by weight or less of lithium bisoxalatoborate , electrolyte salt other than lithium bisoxalatoborate containing lithium, and 0.05% by weight or more of divinyltetraalkyldisiloxane (alkyl having 1 carbon atom) And 4 or less).   The nonaqueous electrolytic solution according to claim 1, comprising 0.2% by weight or more and 5% by weight or less of lithium bisoxalatoborate.   The nonaqueous electrolytic solution according to claim 1 or 2, comprising 0.1 wt% or more and 10 wt% or less of divinyltetraalkyldisiloxane.   The non-aqueous electrolyte according to claim 1, wherein the divinyltetraalkyldisiloxane is divinyltetramethyldisiloxane. A positive electrode having a positive electrode active material;
A negative electrode having a negative electrode active material;
The nonaqueous electrolytic solution according to any one of claims 1 to 4, which is interposed between the positive electrode and the negative electrode and conducts lithium ions,
Lithium ion secondary battery equipped with.

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