JPH02192668A - Secondary cell - Google Patents

Abstract

PURPOSE:To prevent the corrosion of the cell can or the collector of a cell by composing the solvent of the electrolyte with a mixture of a specified normal chain diether compound and a specified ring carbonic ester compound. CONSTITUTION:The solvent of the electrolyte consists of a mixture of a normal chain diether compound indicated in the formula I and a ring carbonic ester compound indicated in the formula II. In this formulae I and II, l indicates 1 or 2, m, n, indicate an integral number more than 1 and less than 4 respectively, R1 indicates a lower alkyl radical or 1-3 in hydrogen atom or carbon number, and R2 indicates a hydrogen atom or a methyl radical. And the vol.% of the mixture of the normal chain diether compound and the ring carbonic ester compound is specified to be 90:10-10:90. Thereby the voltage elevation at the charging time can be suppressed low to prevent the corrosion of the cell can or the collector.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a secondary battery using a conductive polymer in at least one electrode.

(B) Prior Art In recent years, secondary batteries using conductive polymers as electrodes have been proposed, as seen in, for example, Japanese Patent Application Publication No. 136469/1983.

The conductive polymer used for the electrodes of this type of secondary battery usually has a slight conductivity, but it is possible to dope and dope various dopants, and doping dramatically increases the isoelectricity. to rise. And CX
Conductive polyester doped with anions such as 04- and BF4-? - is used as a positive electrode material, and aCt polymer doped with cations such as Li" and Na+ is used as a negative electrode material, and the battery can be charged and discharged by electrochemically reversibly performing doping and undoping. is configured.

Such conductive polymers are generally made by chemical polymerization using an oxidizing agent or electrolytic polymerization, and examples of such conductive polymers include polyacetylene, polypyrrole, polythiophene, polyaniline, polyvaraphenylene, and the like. If this polymer is obtained in powder form, it is pressure-molded into a shape that matches the electrode shape, and if it is in film form, it is used by punching it into the electrode size or by crushing it into powder form. has been done. Batteries using these conductive polymers are expected to be lightweight, have high energy density, and are non-polluting. In particular, the above-mentioned polypyrrole and polyaniline have good properties, and secondary batteries using these are considered promising as practical batteries.

The electrolyte for this type of secondary battery is usually the same as that used in existing non-aqueous batteries such as lithium batteries.
An alkali metal salt such as a lithium salt such as lithium perchlorate or lithium fluoroborate is dissolved as a solute in an aprotic organic solvent such as propylene carbonate.

(c) Problems to be Solved by the Invention However, secondary batteries using these conductive polymers as electrodes generally have a considerably higher electrode potential than existing non-aqueous batteries. Therefore, when a battery is constructed using the above-mentioned conventional electrolyte and charged and discharged, the battery voltage becomes too high as charging progresses, resulting in decomposition of the electrolyte, dopant, and even conductive polymer. There are problems in that side reactions such as these occur, leading to a decrease in charge/discharge efficiency and deterioration of storage characteristics. This tendency is especially noticeable when the charge/discharge capacity is large, and there is also the problem that the degree of decrease in charge/discharge efficiency is large as the cycle progresses, and therefore the cycle life is shortened.

The present invention solves these conventional problems and dramatically improves the cycle characteristics of secondary batteries by preventing a decrease in charge/discharge efficiency and deterioration of storage characteristics. The purpose is to provide a reliable and high-performance secondary battery.

(d) Means for Solving the Problems The present invention provides a secondary battery comprising a positive electrode, a negative electrode, and an electrolyte, and using a conductive polymer only in the positive electrode or in both the positive and negative electrodes, comprising: The electrolytic solution is characterized in that the solvent thereof is a mixed solvent of a linear diether compound represented by the following general formula (a) and a cyclic carbonate ester compound represented by the following general formula (b). It is.

However, C@Ht+s+IQ (CH1) to CmHt*
++"'(a) (where 2 is 1 or 2, m and n are 1
An integer greater than or equal to 4 and less than or equal to 4. ) (In the formula, R3 is a hydrogen atom or a lower alkyl group having 1 to 3 carbon atoms, and R1 is a hydrogen atom or a methyl group.) And here, the mixing volume ratio of the linear diether compound and the cyclic carbonate compound is, The ratio is preferably 90:10 to 10:90.

(E) Effect When a battery is constructed using an organic solvent as an electrolyte as in the present invention, the rise in voltage during charging can be suppressed to a lower level than when only propylene carbonate is used as an electrolyte solvent as in the past. As a result, corrosion of the battery can and current collector can be prevented, and decomposition of the electrolyte, dopant, or conductive polymer can be controlled, and the charging/discharging characteristics and cycle characteristics of the battery can be improved.

The reason why the characteristics are improved when a mixed solvent is used as an electrolyte solvent is considered to be as follows. That is,
The anions used as dopants in this type of battery exist as solvates with the solvent in which they are dissolved in the undoping state, but when a doping reaction occurs, this solvation is removed and the anions themselves become conductive polymers. It is medium-heated. At this time, the ease of desolvation and the ease of doping are greatly influenced by the interaction between the solvent in which the anion is solvated and the conductive polymer to which the anion is doped.

Furthermore, when using a mixed solvent of a linear diether compound and a cyclic carbonate compound as described above, the solvation of the anion and the linear diether tends to come off due to the interaction between the linear diether and the conductive polymer. it is conceivable that.

Further, the fact that the electrolytic solution using the mixed solvent of the present invention has higher conductivity and lower viscosity than the conventional electrolytic solution using propylene carbonate is also considered to be a factor in improving the characteristics.

The linear diether compounds represented by the formula (a) include dimethoxymethane, jetoxyethane, butoxypropoxymethane, ethoxymethoxyethane, and jetoxymethane, and the cyclic carbonate represented by the formula (b) includes propylene. Carbonate, ethylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 2,3-pentene carbonate, etc. can be used.

As the electrolyte for the secondary battery of the present invention, lithium borofluoride (L+BF+), lithium perchlorate (LrC
9O+), lithium hexafluoride phosphate (L i P Fs
), lithium hexafluoride arsenate (L i A.

F4), lithium aluminum tetrachloride (LiAx C
14) etc. can be used.

(f) Examples In the following examples, studies were conducted by varying the combination of the linear diether compound and cyclic carbonate ester and the amount added thereof.

In Experiment I, propylene carbonate was used as the cyclic carbonate; in Experiment 2, ethylene carbonate was used as the cyclic carbonate; in Experiment 3, 1,2-butylene carbonate was used as the cyclic carbonate; In Experiment 4, 2,3-butylene carbonate was used as the cyclic carbonate. In Experiment 5, 1,2-pentene carbonate was used as the cyclic carbonate. In Experiment 6, 2,3-pentene carbonate was used as the cyclic carbonate. An example using , and are shown respectively.

◎ Experiment 1: First example using propylene carbonate as cyclic carbonate ester [Example I] An example of the present invention will be described below based on a flat non-aqueous secondary battery shown in FIG.

The negative electrode 2 made of J-thium metal is pressed onto the inner surface of a negative electrode current collector 7, and this negative electrode current collector 7 is fixed to the inner bottom surface of a negative electrode needle 5 made of stainless steel and having a substantially U-shaped cross section. The peripheral end of the negative electrode needle 5 is fixed inside an insulating backing 8 made of polypropylene, and on the outer periphery of the insulating backing 8 is a positive electrode can made of stainless steel and having a substantially U-shaped cross section in the opposite direction to the negative electrode needle 5. 4 is fixed. A positive electrode current collector 6 is fixed to the inner bottom surface of the positive electrode can 4, and a positive electrode l is fixed to the inner surface of this positive electrode current collector 6. A separator 3 is interposed between the positive electrode 1 and the negative electrode 2.

By the way, the positive electrode 1 was created by pressure-molding polyaniline powder synthesized by electrolytic polymerization into a disk shape, and the negative electrode 2 was created by punching a lithium rolled plate into a predetermined size. In addition, as the electrolytic solution, a solution in which 1M lithium borofluoride (LiBF) was dissolved in an organic solvent was used, and the organic solvent was dimethoxymethane (C, H
, QCH*OC-Hs) and propylene carbonate at a volume ratio of 50:50.

The battery thus produced is hereinafter referred to as (A1) battery.

[Example II to Example ■] As shown in Table 1 below, dimethoxymethane and propylene carbonate were used as organic solvents in a ratio of 95:5, respectively.
．． 90: 10.70: 30, lO: 90.5:
A battery was produced in the same manner as in Example I above, except that the mixture was mixed at a volume ratio of 95%.

The batteries thus produced are classified into the following categories: (A,) battery, (81) battery, (Ai) battery, (A,) battery, (A,
) is called a battery.

Margin below [Comparative Example ■] A battery was produced in the same manner as in Example I above, except that a mixed solvent of γ-butyrolactone and propylene carbonate in a ratio of 50,750 was used as the organic solvent.

The battery thus produced is hereinafter referred to as a pond (Y).

[Comparative Example II] A battery was produced in the same manner as in Example I above, except that propylene carbonate was used as the organic solvent.

The battery thus produced is hereinafter referred to as a (Z)it battery.

U Experiment Regarding the (A1) to (A6) batteries of the present invention and the (Y) battery and (Z) battery of the comparative example, a current of 1 mA was used for 10
After charging for an hour, the battery voltage reached 2.0 mA with a current of 1 mA.
A charge/discharge cycle of discharging until the voltage reached 5V was repeated.

Then, the end-of-charge voltage and charge-discharge efficiency of each battery at the 100th cycle were investigated, and the results are also shown in Table 1 above.

As is clear from Table 1, the comparative example (Y) battery and (Z
) For batteries, the end-of-charge voltage is 4, 55V, and 4.60V, respectively.
And very expensive. In contrast, (A,) of the present invention
The battery and (A6) battery each have a charge end voltage of 4.38.
It was observed that the voltage was 4.40V and had decreased.
Furthermore, the (AI) battery and (A,) battery of the present invention ~ (A5)
What is the end-of-charge voltage for batteries? 3.76V, 3.76V
, 3.77■, and 3.78V, which shows a further decrease.

Furthermore, the charge/discharge efficiency of the (Y) and (Z)TL cells of Comparative Examples was 75% and 65%, respectively, which was a significant decrease.

On the other hand, it was observed that the charging/discharging efficiency of the battery of the present invention (A,) and the battery of (A6) was 83% and 80%, respectively, which was improved. Batteries and (
A.) Batteries to (A5) Batteries all have charge/discharge efficiencies of 100.
%, which shows a further improvement.

From these results, it can be seen that the performance of the (AI) to (As) batteries of the present invention was improved compared to the (Y) battery and (z) battery of the comparative example.

In particular, it can be seen that the performance of the (A1) battery and (A,) battery to (A,) battery has been dramatically improved.

Therefore, the mixing volume ratio of the organic solvent dimethoxymethane and propylene carbonate is 90:1O to 1
A range of 0:90 is desirable.

! - Needle 'xi rotation [Example ■] Jetoxyethane [c*HsO(CH-
) t oct Hs] and propylene carbonate at a volume ratio of 50:50.

The battery thus produced is hereinafter referred to as a (B,) battery.

[Example IT to Example ■] As shown in Table 2 below, diethoxyethane and propylene carbonate were used as organic solvents in a ratio of 95:5, respectively.
A battery was produced in the same manner except that solvents mixed at a volume ratio of 90:10.70:30.10:90.5:95 were used.

The batteries produced in this way are classified into the following categories: (B,), (B,) battery, (B,) battery, CB,) battery, (B,)
) is called a battery.

Below is the margin [Comparative Example 1. II] Comparative examples are shown in Comparative Examples ■ and II in Table 1 above (Y
) batteries and (Z)it ponds were used.

[Experiment] Charging and discharging cycles were repeated under the same conditions as described above for the (B,) TL cell to (B,) battery of the present invention and the (Y) battery and (Z) battery of the comparative example.

Then, the end-of-charge voltage and charge-discharge efficiency of each battery at the 100th cycle were investigated, and the results are also shown in Table 2 above.

As is clear from Table 2, (Y)' in the comparative example is
As mentioned above, the (Z) battery has a very high charge end voltage. On the other hand, the (B8) battery and (B6) of the present invention
It was observed that the end-of-charge voltage of the battery was 436 V and 4.39 V, respectively, which were lower, and furthermore, the (B) of the present invention
The end-of-charge voltage is 3.77 V, 3.76 V, 3.76 V, and 3 for the L) battery and the (B,) battery, respectively.
．． It is recognized that the voltage is 77V, which has further decreased.

In addition, in Comparative Examples (Y) 7rL pond and (Z) TL pond, the charging/discharging electric vehicle performance was significantly reduced as described above. On the other hand, it was recognized that the charging and discharging efficiency of the battery (B,) of the present invention and the battery (B,) of the present invention was 82% and 80%, respectively, which was improved, and the battery (B,) of the present invention And (B,) battery ~ (B,) battery, the charging and discharging efficiency is all 100%, and it is recognized that it is further improved.

From these results, it can be seen that the performance of the batteries (B,) to (B,) of the present invention was improved compared to the (Y) battery and (Z) battery of the comparative example.

In particular, it can be seen that the performance of the (B1) battery and (B,) 71 to (B,) battery has been dramatically improved. Therefore, the mixing volume ratio of the organic solvent jetoxyethane and propylene carbonate is 90:10 to 10:90.
It is desirable that it be within the range of .

Third Example [Example I] Butoxypropoxymethane [C,I-I
, OCH, QC, H,] and propylene carbonate at a volume ratio of 50:50, but a battery was produced in the same manner as in Example 2 of the first example.

The battery thus produced is hereinafter referred to as a (C1) battery.

[Example 1 to Example ■] As shown in Table 3 below, butoxypropoxymethane and propylene carbonate were used as organic solvents at 95:5.90:10.70:30.10:90.5, respectively.
A battery was produced in the same manner except that a solvent mixed at a volume ratio of 95% was used.

The batteries produced in this way were measured in the following order (Ct)?
rL pond, (C3) battery, (C,) pond, (Cs)? 1 is called a pond, and (C6) is called a battery.

The following margins [Comparative Examples ■, II] As comparative examples, (Y) and (Z) batteries in Table 1 were used.

[Experiment Ko (C,)' of the above-mentioned invention ~ (C,)? ! Charge/discharge cycles were repeated under the same conditions as described above for the (Y) battery and (Z) battery of Comparative Example.

The end-of-charge voltage and charging/discharging efficiency of each battery at the 100th cycle were investigated, and the results are also shown in Table 3 above.

As is clear from Table 3, the (Y) battery and (Z
) In IT batteries, the end-of-charge voltage is extremely high as described above. On the other hand, in the present invention, (C,) is a pond and (C6)
For batteries, the end-of-charge voltage is 4°40V and 4.42V, respectively.
However, it was observed that the present invention (
The end-of-charge voltages for the battery C,) and the batteries (C1) to (C3) are 3.78V, 3.79V, 3.77V, and 3, respectively.
．． It is recognized that the voltage is 79V, which is further decreased.

Furthermore, in the comparative examples (Y) battery and (Z) battery, the charging/discharging electric vehicle performance was significantly decreased as described above. On the contrary,
It was recognized that the charge/discharge efficiency of the battery (C1) and the battery (C1) of the present invention was 80% and 79%, respectively, which were improved, and furthermore, the battery (C1) and the battery (C1) of the present invention were improved.
, ), the charging and discharging efficiencies were all 100%, indicating further improvement.

From these results, it can be seen that the performance of the (C,) battery to (C,) pond of the present invention was improved compared to the (Y) battery and (Z) battery of the comparative example.

In particular, it can be seen that the performance of the (C,) battery and (C3) battery ~ ((,) 1 battery has been dramatically improved.

Therefore, the mixing volume ratio of butoxypropoxymethane and propylene carbonate, which are organic solvents, is 90:1.
A range of 0 to 1190 is desirable.

[Example I] Ethoxymethoxyethane [C=HsO] as the organic solvent
(CH-) tOCHs] and propylene carbonate at a volume ratio of 50:50, but a battery was produced in the same manner.

The battery thus produced is hereinafter referred to as a (Dl) battery.

[Example II to Example ■] As shown in Table 4 below, ethoxymethoxyethane and propylene carbonate were each used as an organic solvent at 9%
5:5.90: 10.70:30.10:90.5
A battery was produced in the same manner except that a solvent mixed at a volume ratio of :95 was used.

The batteries produced in this way are listed below in the following order: (D,) battery, (D,) battery, (D,) battery, (D,) battery, (D,
) is called a battery.

The following margins [Comparative Examples I and II Comparative Examples include (Y) battery and (Z) battery shown in Table 1 above.
Batteries were used.

[Experiment] Charging and discharging cycles were repeated under the same conditions as described above for the above-mentioned batteries (D,) to (D,) of the present invention and the (Y) battery and (Z) battery of the comparative example.

Recently, the end-of-charge voltage and charging/discharging efficiency of each battery at the 100th cycle were investigated, and the results are also shown in Table 4 above.

As is clear from Table 4, (Y) of the comparative example is pond, (
Z) As mentioned above, the end-of-charge voltage of batteries is extremely high. On the other hand, the (D,) battery of the present invention and (D,)i
It was observed that the end-of-charge voltage of the T battery was 4.36 V and 4.38 V, respectively.
, ) battery and (I) l) Z battery to (Ds) battery, the charge end voltage is 3.76V, 3.77V, 3.76V, respectively.
It is recognized that the voltage is 3.78V, which is further decreased.

Furthermore, in the comparative examples (Y) battery and (Z) battery, the charging/discharging electric vehicle performance was significantly decreased as described above. On the contrary,
The present invention (D,) and (D,)71! It was recognized that the charging and discharging efficiency of the batteries was 84% and 82%, respectively, which was improved, and the (Dl) battery and (D,) battery of the present invention
(D,) The charging and discharging efficiencies of the batteries were all 100%, indicating further improvement.

From these results, it can be seen that the (D,) wo-ike to (D6) batteries of the present invention have improved performance compared to the (Y)i-ike and (Z) batteries of the comparative examples.

In particular, the (Dl) battery and the (D,) battery to (D,) battery are
It can be seen that the performance has improved dramatically. Therefore, the mixing volume ratio of the organic solvent ethoxymethoxyethane and propylene carbonate is 90:10 to 10:9.
A range of 0 is desirable.

As in the first to fourth embodiments in Experiment 1, (A1) to (A,) battery, (B,) battery to
(B6) Battery, (C,) Pond ~ (C1) Battery, l, ) Pond ~ (D6) TL Pond is Comparative Example (Y) Pond and (Z
) The improved performance compared to batteries is thought to be due to the following reasons.

That is, when a mixed solvent of a linear diether compound and propylene carbonate is used as a solvent for the electrolytic solution as in Experiment 1, the solvation of the anion and the linear diether compound is caused by the solvation of the linear diether compound and the conductive polymer. This is thought to be due to the fact that the conductive polymer becomes easily detached due to the interaction between the two, and hair anions are easily doped into the conductive polymer.

Also, if the above mixed solvent is used as a solvent for the electrolyte,
Compared to conventional electrolytic solutions using only propylene carbonate as a solvent, the conductivity is higher and the viscosity is lower, which is thought to contribute to improved battery performance.

◎ Experiment 2: First example using ethylene carbonate as the cyclic carbonate ester [Example ■] A battery was obtained in the same manner as Example ■ of the first example of Experiment 1, and the following organic solvent was used as the electrolyte. Use 1 mat/L of lithium fluoroborate dissolved in it. As an organic solvent, jetoxymethane (C, H, OCH, QC, H
5) and ethylene carbonate are used.

The battery produced as described above is hereinafter referred to as (E,) battery.

[Example 11 to Example ■] As shown in Table 5 below, jetoxymethane and ethylene carbonate were used as organic solvents in a ratio of 95:5.9, respectively.
A battery was prepared in the same manner as in Example 2 above, except that they were mixed at a volume ratio of 0:10.70:30.10:90.5:95.

The batteries produced in this way are categorized as (E) batteries, (
They are referred to as E,) battery, (E3) battery, (E,) battery, and (E,) battery.

Comparative Example (2) A battery was prepared in the same manner as in Example (2) except that a 50:50 mixed solvent of γ-butyrolactone and propylene carbonate was used as the organic solvent.

Hereinafter, the battery produced in this manner will be referred to as a (y) battery.

[Comparative Example II] A battery was produced in the same manner as in Example I above, except that propylene carbonate was used as the organic solvent.

Hereinafter, the battery produced in this manner will be referred to as a (Z) battery.

Each battery was repeatedly charged and discharged using a 1 mA current for 10 hours and then 1 mA current until the battery voltage reached 2.5V. The end-of-charge voltage and charge-discharge efficiency of each battery at the 100th cycle are shown in Table 5.

From Table 5, the (Y)'u battery and the (Z) battery of the comparative example have deteriorated with charge end voltages of 4, 55 V, and 4.60 V, respectively, and charging and discharging efficiencies of 75% and 65%. Furthermore (El
) battery and (F6) battery each have a charge end voltage of 4.4.
0V, 4.41V, and charge/discharge efficiency of 80% and 81%, whereas batteries (E,) to (E,) of the present invention have charge end voltages of 3.78V, 3.78V, and 3.78V, respectively. 79V,
The characteristics are extremely good, with a voltage of 3.80V and a charge/discharge efficiency of 100%.

Based on these facts, the mixing volume ratio of jetoxymethane and ethylene carbonate, which are organic solvents, is 90:10 to 90:10.
A range of 10:90 is desirable.

Below is a blank space for Example 2 [Example 1 to Example ■C] As shown in Table 6 below, jetoxyethane (C, H, O(CH,), OC, F2) and ethylene carbonate were used as organic solvents. 95:5.90:10 respectively.
70: 30.50: 50.10°90.5:9
A battery was produced in the same manner as described above, except that the mixture was mixed at a volume ratio of 5.

The batteries produced in this way are as follows: (Fl) battery, (Fl) battery, (Fs) battery, (F4) battery, (F
, ) battery, (F,) battery.

In addition, as comparative examples, (Y)TL pond and (Z
) A TL pond was used.

Each battery was charged with a current of 1 mA for 10 hours, and then discharged with a current of 1 mA until the battery voltage reached 2.5 V, and a charge/discharge cycle was repeated. and,
Table 6 shows the end-of-charge voltage and charge-discharge efficiency of each battery at the 100th cycle.

From Table 6, the (Y)TL battery and the (Z) battery of the comparative example have degraded end-of-charge voltages of 4.55 V and 4.60 V, respectively, and charging and discharging efficiencies of 75% and 65%. Furthermore (F+) TL pond,
(F6) Each battery has a charging end 71E voltage of 4.39V,
4.40V and charge/discharge efficiency of 83% and 82%, whereas the batteries (F2) to (F,) of the present invention have charge end voltages of 3.77V, 3.77■, 3.76V, respectively. 3.
It has extremely good characteristics, with a voltage of 78V and a charge/discharge efficiency of 100%.

From these facts, the mixing volume ratio of the organic solvent jetoxyethane and ethylene carbonate is 90:10 to 90:10.
A range of 1.0:90 is desirable.

The following margins are 3*m down [Example ■ to Example ■] As shown in Table 7 below, butoxypropoxymethane (C, H, OCH, 0C3Ht) and ethylene carbonate were mixed as organic solvents in a ratio of 95:5 to 95:5, respectively. .90:101
A battery was produced in the same manner as described above except that the mixtures were mixed at a volume ratio of 70:30.50:50.10:90.5:95.

The batteries produced in this way are classified into the following categories: (G1) battery, (G,) battery, (G,) battery, (G4) battery, (G
, ) is called a pond and (G,) battery.

In addition, as comparative examples, the (Y) battery and (Z) battery shown in Table 7 are
Batteries were used.

Each battery was charged for 10 hours with a current of 1 mA,
Further, charge/discharge cycles were repeated in which the battery was discharged with a current of 1+nA until the battery voltage reached 2.5V. Table 7 shows the end-of-charge voltage and charge-discharge efficiency of each battery at the 100th cycle.

From Table 7, the battery (Y) and the battery (Z) of the comparative example have degraded charge end voltages of 4.55 V and 4.60 V, and charge/discharge efficiencies of 75% and 65%, respectively. Furthermore (G,) battery,
(G6) The battery has a charge end voltage of 4.42V and 4.
．． 43V, charging/discharging efficiency is 80%, 79%,
In particular, the batteries (G,) to (G,) of the present invention have charge end voltages of 3.79V, 3.78V, 3.79V, and 3.8V, respectively.
0V, charge/discharge efficiency 1. The properties are extremely good with O0%.

From these facts, the mixing volume ratio of the organic solvent jetoxyethane and ethylene carbonate is 90:10.
It is desirable that the ratio is in the range of ~10:90.

Below is a blank space for Example 4 [Example I to Example ■] As shown in Table 8 below, ethoxymethoxyethane (C, H, O (CH, OCH,) and ethylene carbonate were used as organic solvents, respectively. 95:5.90:10.
A battery was produced in the same manner as above except that the mixtures were mixed at a volume ratio of 70:30.50:50.10:90.5:95.

The batteries produced in this way are listed in the following order: (Hl) battery, (H2) battery, (H,)? It pond, (H6) battery,
It is called (H6) battery and (Hs)it battery.

In addition, as comparative examples, (Y) batteries and (Z) batteries shown in Table 8 are used.
Used batteries.

Each battery was charged for 10 hours with a current of 1 mA,
Further, charging and discharging cycles were repeated in which the battery was discharged with a current of 1 mA until the battery voltage reached 2.5 V. The end-of-charge voltage and charge-discharge efficiency of each battery at the 100th cycle are shown in Table 8.

From Table 8, the (Y) battery and (Z) battery of the comparative example have degraded end-of-charge voltages of 4.55 V and 4.60 V, and charging and discharging efficiencies of 75% and 65%, respectively. Furthermore, (Hl) battery, (
H6) TL batteries have charge end voltages of 4.38V and 4.
．． 39V, charge/discharge efficiency of 84%, 82%,
In particular, the batteries (H, ) to (H6) of the present invention have charge end voltages of 3.77V, 3.77V, 3.76V, and 3.7V, respectively.
The characteristics are extremely good, with a voltage of 8V and a charge/discharge efficiency of 100%.

From these facts, the mixing volume ratio of the organic solvent ethoxymethoxyethane and ethylene carbonate is 90
The ratio is preferably in the range of :10 to 10:90.

Space below ◎ Experiment 3: Using 1,2-butylene carbonate as the cyclic carbonate [Example I to Example ■] As shown in Table 9 below, ethoxymethoxyethane and 1,2-butylene were used as the organic solvents. 9 each.
5; 5.90: 10.70: 30, so: so, 10:
A battery was produced in the same manner as described above, except that they were mixed at a volume ratio of 90.5:95.

The batteries produced in this way are listed in the following order: (11) battery, (I,) battery, (I,) battery, (■,) battery, (■,
) battery, (1,) battery.

In addition, as a comparative example, (Y) shown in Table 9 is pond, (Z
) using a pond.

Each battery was charged for 10 hours with a current of 1 mA,
Further, charging and discharging cycles were repeated in which the battery was discharged with a current of 1 mA until the battery voltage reached 2.5 V. The end-of-charge voltage and charge-discharge efficiency of each battery at the 100th cycle are shown in Table 9.

From Table 9, the (Y) battery and (Z) battery of the comparative example have degraded end-of-charge voltages of 4.55 V and 4.60 V, respectively, and charging and discharging efficiencies of 75% and 65%. Furthermore, (I,) battery, (
1,) The batteries have a charging end voltage of 4.40V, 4.
42V and charge/discharge efficiency of 83% and 80%, respectively, whereas the batteries (I,) to (I,) of the present invention have charge end voltages of 3.39V, 3.38V, 3.37V, and 3.3V, respectively. 39
V, the charging and discharging efficiency is 100%, and the characteristics are extremely good.

For these reasons, it is desirable that the mixing volume ratio of the organic solvent ethoxymethoxyene and 1,2-butylene carbonate be in the range of 90: ], 0 to 10:90.

Space below ◎ Experiment 4: Using 2,3-butylene carbonate as the cyclic carbonate [Example I to Example ■] As shown in Table 10 below, ethoxymethoxyethane and 2,3-butylene were used as the organic solvents. and 95 each
:5.90:10.70:30.50:50.102 A battery was produced in the same manner as above except that the mixture was mixed at a volume ratio of 90.5:95.

The batteries produced in this way are classified into the following categories: (Jl) battery, (J,) TL battery, (J,) battery, (J,) battery, (J
, ) battery, (J,) battery.

In addition, as comparative examples, the (Y) battery shown in Table 10, (
Z) A battery was used.

Each battery was repeatedly charged and discharged using a 1 mA current for 10 hours and then 1 mA current until the battery voltage reached 2.5V. Table 10 shows the end-of-charge voltage and charge-discharge efficiency of each battery at the 100th cycle.

From Table 10, the (Y) battery and (Z) battery of the comparative example have degraded end-of-charge voltages of 4.55 V and 4.60 V, and charge/discharge efficiencies of 75% and 65%, respectively.

Furthermore, the (J,) battery and (J6) battery have charge end voltages of 4.41V and 4.43V, respectively, and charge/discharge efficiency of 81% and 79
%, whereas the batteries (J,) to (J,) of the present invention have end-of-charge voltages of 3°77V, 3.78V, and 3.78V, respectively.
The characteristics are extremely good: 3.78V, 3.79V, and 100% charge/discharge efficiency.

For these reasons, the mixing volume ratio of the organic solvent ethoxymethoxyethane and 2,3-butylene carbonate is preferably in the range of 90:10 to 10:90.

Blank space below ◎ Experiment 5: Using l,2-pentene carbonate as the cyclic carbonate [Example I to Example ■] As shown in Table 11 below, ethoxymethoxyethane and 1,2-pentene were used as organic solvents. and 95 each
:5.90:10.70:30.50 :50.10
A battery was produced in the same manner as described above except that the mixture was mixed at a volume ratio of :90.5:95.

The batteries produced in this way are listed in the following order: (K1) battery, (K,) battery, (K,) battery, (K,)! Pond, (K
i) 1 pond, (K,) is called TL pond.

In addition, as a comparative example, Table 11 shows (YI [ike, (Z
) using batteries.

Each battery was charged for 10 hours with a current of 1 mA,
Further, charging and discharging cycles were repeated in which the battery was discharged with a current of 1 mA until the battery voltage reached 2.5 V. Table 11 shows the end-of-charge voltage and charge-discharge efficiency of each battery at the 100th cycle.

From Table 11, the (Y) battery and (Z) battery of the comparative example have degraded charge end voltages of 4.55 V and 4.60 V, respectively, and charging and discharging efficiencies of 75% and 65%.

Furthermore, the (K1) battery and (K,) battery have charge end voltages of 4.43V and 4.44V, respectively, and charging and discharging efficiencies of 79% and 78%.
%, whereas the (K,) to (K,) batteries of the present invention have charge end voltages of 3°79V and 3.79V, respectively.
, 3.78V, 3.79V, and the charging/discharging efficiency is 100%, which shows extremely good characteristics.

For these reasons, the mixing volume ratio of the organic solvent ethoxymethoxyethane and 1,2-pentene carbonate is preferably in the range of 90:10 to 10:90.

Space below ◎ Experiment 6...Using 2,3-pentene carbonate as a cyclic carbonate [Example I to Example ■] As shown in Table 12 below, ethoxymethoxyethane and 2,3-pentene were used as organic solvents. and 95 each
:5.90:10.70:30.50:50.10:9
A battery was produced in the same manner as described above, except that the mixture was mixed at a volume ratio of 0.5:95.

The batteries produced in this way are classified into the following categories: (L,) battery, (L,) battery, (L,) battery, (L,) TLM,
(Ls) is called a pond, and (Lg) it is called a pond.

In addition, as a comparative example, (Y) shown in Table 12 is used as a pond, (
Z) A battery was used.

Each battery was charged for 10 hours with a current of 1 mA,
Further, charging and discharging cycles were repeated in which the battery was discharged with a current of 1 mA until the battery voltage reached 2.5 V. Table 12 shows the end-of-charge voltage and charge-discharge efficiency of each battery at the 100th cycle.

From Table 12, the (Y) battery and (Z) battery of the comparative example have degraded end-of-charge voltages of 4.55 V and 4.60 V, and charging and discharging efficiencies of 75% and 65%, respectively.

Furthermore, the (Ll) battery and the (L,) battery have charge end voltages of 4.43 V and 4.42'V, respectively, and a charge/discharge efficiency of 80% and 8
2%, whereas in particular the present invention's (L,) to (L,)
The batteries have a charge end voltage of 3°79V and 3,78V respectively.
V, 3.79V, 3.78V, charging/discharging efficiency of 100%, and the characteristics are extremely good.

For these reasons, it is desirable that the mixing volume ratio of the organic solvent ethoxymethoxyethane and 2,3-pentene carbonate is in the range of 90:10 to 10:90.

The reason why the voltage during charging decreased and the performance improved, especially in the batteries of Experiments 1 to 6, is considered to be due to the following reasons.

That is, the linear diether shown by the former (a) and the former (
When a mixed solvent of cyclic carbonate compounds as shown in b) is used, the solvation of the anion and the linear diether becomes easier due to the interaction between the linear diether and the conductive polymer, resulting in hair anions in the conductive Bommer. It is thought that doping becomes easier. It is also believed that the fact that the electrolytic solution using this mixed solvent has a higher conductivity and lower viscosity than the conventional electrolytic solution using only propylene carbonate is also a factor in improving the characteristics.

In Experiments 1 to 6 above, the electrode made of conductive Bommer was used only for the positive electrode, but the same effect as described above can be obtained even when it is used for both the positive electrode and the negative electrode.

In addition, in Experiments 1 to 6, lithium metal was used for the negative electrode, but alloys of lithium and at least one selected from the group consisting of aluminum, bismuth, lead, tin, cadmium, indium, and zinc, manganese, and chromium ,
Of course, the same effect can be obtained when using a lithium-aluminum alloy or a conductive polymer containing at least one metal selected from the group consisting of iron, silicon, copper, zirconium, tungsten, and molybdenum.

Furthermore, in the above experiments 1 to 5, lithium borofluoride was used as the electrolyte of the electrolytic solution, but it is not limited to this, and lithium perchlorate (L + CNO +)
, lithium hexafluorophosphate (LiPF, ), lithium hexafluoroarsenate (LiAsF, ), lithium aluminum tetrachloride (LiAI!.

C2, ) etc. may be used.

(g) As described in detail, according to the present invention, the voltage increase during charging can be suppressed to a low level, so corrosion of the battery can and current collector can be prevented, and the electrolyte and Decomposition of the dopant or conductive polymer is suppressed. In addition, if the above mixed solvent is used as a solvent for the electrolyte,
Compared to conventional electrolytes using only propylene carbonate as a solvent, the conductivity is higher and the viscosity is lower.

For these reasons, the charging/discharging characteristics and cycle characteristics of the battery can be improved, and a highly reliable and high-performance secondary battery can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a battery according to an example. 1...Positive electrode, 2...Negative electrode, 3...Separator.

Claims (1)

[Claims] (1) In a secondary battery comprising a positive electrode, a negative electrode, and an electrolytic solution, in which a conductive polymer is used only in the positive electrode or in both the positive and negative electrodes, the solvent of the electrolytic solution is expressed by the following general formula (a). A secondary battery comprising a mixed solvent of a linear diether compound represented by the formula (b) and a cyclic carbonate compound represented by the following general formula (b). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(a) (In the formula, l is 1 or 2, m, n are integers from 1 to 4.) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(b) (In the formula, R_1 is a hydrogen atom or a lower alkyl group having 1 to 3 carbon atoms, and R_2 is a hydrogen atom or a methyl group.) (2)
The secondary battery according to claim 1, wherein the mixing volume ratio of the linear diether compound and the cyclic carbonate compound is 90:10 to 10:90.