JP5676733B1 - Electrolyte solution, lithium battery and electrochemical carrier structure - Google Patents

Abstract

An electrolyte solution, a lithium battery, and an electrochemical carrier structure are provided. An electrolyte solution includes 0.1 to 15 parts by weight of an additive with respect to 100 parts by weight of a mixed solution of 81 to 88 parts by weight of an organic solvent and 12 to 19 parts by weight of a lithium salt. The structure of is as follows. [P is 5-31, q is 1-5, r is 9-40, x is 3-40, y is 1-31, and each z is independent, 1-40]

Description

  The present invention relates to an electrolyte solution, and in particular to the composition of the additive.

  Current portable electronic products such as digital cameras, mobile phones, and notebook computers require lightweight batteries. Among various types of batteries, the unit weight of a lithium battery that can be charged in duplicate is three times higher than that of conventional batteries such as a lead storage battery, a nickel hydrogen rechargeable battery, a nickel zinc battery, and a nickel cadmium battery. In addition, lithium batteries can be charged quickly.

Of the lithium batteries, the cathode material is typically a transition metal oxide, such as LiNiO ₂ , LiCoO ₂ , LiMn ₂ O ₄ , LiFePO ₄ , or LiNi _x Co _1-x O ₂ . The anode material is typically lithium metal, an alloy of lithium and other metals, or a carbonaceous material such as graphite. The electrolyte is liquid or solid, and among the solid electrolytes, a polymer electrolyte is particularly attracting attention. This is because the polymer electrolyte does not flow out of the liquid and is easy to prepare. Polyelectrolytes are further divided into complete solid or gel bodies. The difference between the two is that the gel body contains an organic electrolyte solution and no solid.

  Taiwan Patent Publication No. I384668 discloses an electrolyte of an organic aprotic solvent, at least one salt and at least one chelate borate additive.

  Taiwan Patent Publication No. I376828 (Patent Document 2) discloses an electrolyte solution containing an organic solvent, a lithium salt, and an additive. Additives include maleimide, bismaleimide, polymaleimide, polybismaleimide, copolymer of bismaleimide and polymaleimide, or mixtures of the above And vinylene carbonate.

  In general, conventional aqueous electrolyte solutions are not suitable for lithium batteries. This is because water and lithium in the anode produce a violent reaction. Therefore, it is necessary to change the solvent for dissolving the lithium salt into an organic solvent, and these organic solvents need to have characteristics such as high ion conductivity, high dielectric constant, and low viscosity. However, since there are few organic solvents having these three characteristics at the same time, a mixed solvent is a preferred choice. Therefore, there is a need for a new electrolyte solution composition that further increases the efficiency of the lithium battery.

Taiwan Patent Application Publication No. I384668 Specification Taiwan Patent Application Publication No. I376828 Specification

  The present invention aims to provide an electrolyte solution, a lithium battery and an electrochemical carrier structure.

  The electrolyte solution according to an embodiment of the present invention includes 0.1 to 15 parts by weight of an additive with respect to 100 parts by weight of a mixed solution of 81 to 88 parts by weight of an organic solvent and 12 to 19 parts by weight of a lithium salt. The structure of the additive is as follows:

式中、ｐは５から３１の間；ｑは１から５の間；ｒは９から４０の間；ｘは３から４０の間；ｙは１から３１の間；および各ｚはそれぞれ独立し、１から４０の間である。

Where p is between 5 and 31; q is between 1 and 5; r is between 9 and 40; x is between 3 and 40; y is between 1 and 31; and each z is independently Between 1 and 40.

  The lithium battery which concerns on one Embodiment of this invention contains the above-mentioned electrolyte solution.

  An electrochemical carrier structure according to an embodiment of the present invention includes the electrolyte solution described above.

  The electrolyte solution containing the additive according to the present invention can effectively improve the battery capacity.

It is a curve comparison figure of the battery capacity (amp hours, Ah) and charge / discharge frequency in one embodiment of the present invention.

  The electrolyte solution according to an embodiment of the present invention includes 0.1 to 15 parts by weight of an additive with respect to 100 parts by weight of a mixed solution of 81 to 88 parts by weight of an organic solvent and 12 to 19 parts by weight of a lithium salt. And is shown in equation (1).

  In formula (1), p is between 5 and 31. When the value of p is too small, there are few alkoxy groups, the effect of associative transmission with lithium ions is poor, and lithium battery performance is reduced. In formula (1), q is between 1 and 5. When the numerical value of q is excessive, there are few alkoxy groups to be grafted, the effect of associative transmission with lithium ions is poor, and the lithium battery performance is lowered. In the formula (1), r is between 9 and 40. In formula (1), x is between 3 and 40. If the value of x is excessive, the effect of associative transmission with lithium ions is poor and the lithium battery performance is reduced. In formula (1), y is between 1 and 31. In formula (1), each z is independent and is between 1 and 40.

  The method for synthesizing the above-described additive is as follows. First, poly (oxyalkylene) -amine and glycidyl methacrylate (Glycidyl Methacrylate) are mixed, put into tetrahydrofuran (Tetrahydrofuran, THF), heated at 60 to 80 ° C., and 4- React for 12 hours. The reaction formula is shown in Formula (2).

  In the formula (2), poly (oxyalkylene) -amine is a commercially available JEFFAMINE® series, for example, M-600 (x = 9, y = 1), M-1000 (x = 3). , Y = 19), M-2005 (x = 29, y = 6), or M-2070 (x = 10, y = 31).

  Subsequently, the product of formula (2), tris (2-methoxyethoxy) vinyl) silane, poly (methysiloxane), and platinum catalyst (Platinum catalyst) and hydrosilylation catalytic reaction (J. Appl Electrochem (2009) 39: 253). The reaction equation is shown in equation (3):

  In formula (3), poly (methysiloxane) can be purchased from Aldrich (# 176206, n is between 26 and 51) and tris (2-methoxyethoxy) vinyl) silane (Tris (2-methoxyethoxy) (vinyl) silane) can be purchased from Aldrich (# 175587). What can be understood is that the product of formula (3) is a random copolymer.

  In one embodiment of the present invention, the organic solvent may be γ-butyrolactone, Ethylene carbonate, Propylene carbonate, Diethyl carbonate, Propyl acetate, Carbonic acid. Preferably, it includes dimethyl carbonate, ethyl methyl carbonate, or a combination of the above. On the basis of 100 parts by weight of the mixed solution of the organic solvent and the lithium salt, the organic solvent in the mixed solution is 81 to 88 parts by weight.

In one embodiment of the present invention, the lithium _{salt, LiPF 6, LiBF 4, LiAsF} 6, LiSbF 6, LiClO 4, LiAlCl 4, LiGaCl 4, LiNO 3, LiC (SO 2 CF 3) 3, LiN (SO 2 CF ₃ ) ₂ , LiSCN, LiO ₃ SCF ₂ CF ₃ , LiC ₆ F ₅ SO ₃ , LiO ₂ CCF ₃ , LiSO ₃ F, LiB (C ₆ H ₅ ) ₄ , LiCF ₃ SO ₃ , or a combination of the above Is preferred. Based on 100 parts by weight of the mixed solution of the organic solvent and the lithium salt, the lithium salt in the mixed solution is 12 to 19 parts by weight. When the amount of the lithium salt used is too large, the lithium salt cannot be completely dissolved in the electrolyte, and the lithium salt is deposited to lower the conductivity of the electrolyte solution. Conversely, if the amount of lithium salt used is too small, the electrolyte solution cannot have sufficient conductivity.

  Based on 100 parts by weight of the mixed solution of the organic solvent and the lithium salt, the additive in the electrolyte solution is 0.1 to 15 parts by weight. If the additive ratio is too high, too much additive will cause a decrease in volume. If the additive ratio is too low, the performance of the lithium battery or electrochemical carrier structure cannot be improved.

  A lithium ion battery can be manufactured as follows, for example. First, the above-mentioned organic solvent, lithium salt, and additive are mixed in a necessary ratio to form an electrolyte solution. The mixing method is, for example, injected into a standard lithium ion battery by stirring, sonication, or a combination of the above. A positive electrode plate is manufactured based on a standard lithium ion battery positive electrode plate manufacturing method. A standard negative electrode plate is manufactured using a standard lithium ion battery negative electrode paste. The standard battery core (Jelly Roll) is formed by combining the positive and negative electrodes, and the scale is 3.5 mm (height), 58 mm (width), 120 mm (length), that is, 3558120 standard battery core, When 7.8 grams of liquid electrolyte is injected to form a package, the lithium ion battery according to this embodiment is obtained.

  In order to make the aforementioned and other objects, features and advantages of the present invention more comprehensible, examples and figures are described below.

Example 1
As shown in Formula (2), 0.6 mol of glycidyl methacrylate (Glycidyl Methacrylate) and 0.6 mol of poly (oxyalkylene) -amine (JEFFAMINE® 2070, x = 10, y = 31) was placed in 100 mL of tetrahydrofuran (Tetrahydrofuran, THF) and heated at 60 ° C. to 80 ° C. for 4 hours to synthesize a product represented by formula (2). .

  Subsequently, as shown in Formula (3), 1 mole of poly (methysiloxane) (Aldrich # 176206), 0.6 moles of the product of Formula (2), 0.3 Additives are reacted by reacting Mole of Tris (2-methoxyethoxy) (vinyl) silane (Aldrich # 175587) and 0.1-1 mole of platinum catalyst. did. This additive is shown in Formula (1), p is 16 to 31, q is 3 to 5, r is 9 to 15, x is 35, y is 6, and z is 1.

90 parts by weight of LiCoO ₂ , 5 parts by weight of PVDF, and 5 parts by weight of acetylene black (conductive powder) were dispersed in N-Methyl-2-pyrrolidone (NMP), This gel body was applied to an aluminum foil, dried, compressed and cut to form a negative electrode.

  95 parts by weight of graphite and 5 parts by weight of PVDF were dispersed in NMP, this gel body was applied to an aluminum foil, dried, compressed, and cut to form a positive electrode.

18.4 parts by weight of propylene carbonate (PC), 30.7 parts by weight of ethylene carbonate (EC), and 37.1 parts by weight of diethyl carbonate (DEC), An organic solvent for the electrolyte solution was used. LiPF ₆ (13.8 parts by weight) as a lithium salt was dissolved in this organic solvent to prepare a mixed solution of the organic solvent and the lithium salt (total 100 parts by weight). Additives were added to this mixed solution to obtain an electrolyte solution. The additive of the electrolyte solution is as described above (1 part by weight).

  Subsequently, after the anode and the cathode were separated from each other by the separator (PP), the above-described electrolyte solution was added to the accommodation region between the anode and the cathode. Finally, the above structure was packaged in a package structure.

Comparative Example 1
Comparative Example 1 is similar to Example 1 except that the electrolyte solution does not contain the additive of the present invention.

  The batteries of Example 1 and Comparative Example 1 were charged and discharged with a fixed current / voltage. First, at a fixed current of 2.4 mA, the battery was charged to 4.2 V until the current became 0.1 mA or less, and the measured capacity (amp hour, Ah) is shown in Table 1. Subsequently, the battery was discharged with a fixed current of 2.4 A until the cut-off voltage (2.75 V) was reached. The above process was repeated 300 times. Curves of the battery capacity (amp hours, Ah) and the number of times of charging / discharging in Example 1 and Comparative Example 1 are shown in FIG.

  As can be seen from FIG. 1, the battery capacity of Example 1 of the present invention is about 10% to 15% higher than that of Comparative Example 1, and the battery capacity is about 30% to 40% higher after 350 charge / discharge cycles. . As can be seen from the above data, the electrolyte solution containing the additive according to the present invention can effectively improve the battery capacity.

Example 2
Example 2 is similar to Example 1 except that the additive content in the electrolyte solution of Comparative Example 1 is 0.1 parts by weight.
The battery was charged to 4.2 V with a fixed current of 2.4 mA until the current became 0.1 mA or less, and its capacity (amp hour, Ah) was measured and shown in Table 1.

Example 3
Example 3 is similar to Example 1 except that the additive content in the electrolyte solution of Comparative Example 1 is 5 parts by weight.
The battery was charged at 4.2 V until the current became 0.1 mA or less at a fixed current of 2.4 mA, and its capacity (amp hour, Ah) was measured and shown in Table 1.

Example 4
Example 4 is similar to Example 1 except that the additive content in the electrolyte solution of Comparative Example 1 is 10 parts by weight.
The battery was charged at 4.2 V at a fixed current of 2.4 mA until the current became 0.1 mA or less, and its capacity (amp hour, Ah) was measured.

Example 5
Example 5 is similar to Example 1 except that the additive content in the electrolyte solution of Comparative Example 1 is 15 parts by weight.
The battery was charged at 4.2 V until the current became 0.1 mA or less at a fixed current of 2.4 mA, and its capacity (amp hour, Ah) was measured and shown in Table 1.

  Although preferred embodiments of the present invention have been disclosed in the present invention as described above, these are not intended to limit the present invention in any way, and any person who is familiar with the technology can make various modifications within the spirit and scope of the present invention. Variations and moist colors can be added, so the protection scope of the present invention is based on what is specified in the claims.

Claims (5)

An electrolyte solution,
0.1 to 15 parts by weight of an additive is added to 100 parts by weight of a mixed solution of 81 to 88 parts by weight of an organic solvent and 12 to 19 parts by weight of a lithium salt,
The structure of the additive is:

Where p is between 5 and 31;
q is between 1 and 5;
r is between 9 and 40;
x is between 3 and 40;
An electrolyte solution characterized in that y is between 1 and 31; and each z is independently between 1 and 40.   The organic solvent includes γ-butyrolactone, γ-butyrolactone, ethylene carbonate, propylene carbonate, diethyl carbonate, propyl acetate, dimethyl carbonate, carbonic acid. The electrolyte solution according to claim 1, comprising ethyl methyl carbonate or a combination of the above. The lithium salt is LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiSbF ₆ , LiClO ₄ , LiAlCl ₄ , LiGaCl ₄ , LiNO ₃ , LiC (SO ₂ CF ₃ ) ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiSCN, LiO ₃ SCF ₂ CF ₃ , LiC ₆ F ₅ SO ₃ , LiO ₂ CCF ₃ , LiSO ₃ F, LiB (C ₆ H ₅ ) ₄ , LiCF ₃ SO ₃ , or a combination of the above, Or the electrolyte solution of 2.   It is a lithium battery, Comprising: The lithium battery characterized by including the electrolyte solution as described in any one of Claim 1 to 3.   An electrochemical carrier structure comprising the electrolyte solution according to any one of claims 1 to 3.

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