JPS61128479A - High polymer electrode for secondary battery - Google Patents

Abstract

PURPOSE:To increase the capacity of a secondary battery and lengthen its life by sticking chemical compounds consisting of specific hipolymer substance and an additive made with conductive powder and fluorine resin powder to a conductive,grid-shaped supporter. CONSTITUTION:Compounds consisting of a polymer with 4,4',4''-triphenylamine structure or its derivative structure 55-95wt% and an additive 5-45wt% comprising conductive powder and fluorine resin are adhered to a conductive grid- shaped supporter. As a derivative of 4,4',4''-triphenylamine, 4,4'-(4''-substitution or non-substitution) triphenylamine, etc. are used. As conductive powder, substances not reactive to electrolyte or active material and stabilized electro- chemically such as platina are used. As fluorine resin, polytetrafluorethylene, etc. are used. Based on such arrangment, it is possible to increase the capacity of the secondary beattery and lengthen its life.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to an electrode for secondary batteries that uses a high molecular weight polymer as an active material.

[Conventional technology]

In recent years, secondary electrodes have been developed that include an organic electrolyte and an electrode using a polymeric material as an active material. Polyacetylene is known as a typical example of a polymeric material used as an active material. As a secondary battery using this polyacetylene as an electrode, electrochemical society 50th conference abstracts wJ
According to page 53, propylene carhone) 1c I
Using an electrolyte bathed with i, 1 ctoa at a concentration of M/lO,
It has been reported that charging and discharging could be repeated 30 to 40 times with high current efficiency.

[Problems to be Solved by the Invention] Electrodes for secondary batteries using such polyacetylene as an active material have problems in that the amount of electricity that can be drawn out per unit weight is not necessarily high, and the cycle life may be short. there were.

[Means for solving problems]

This invention was developed by focusing on such conventional problems, and it is a polymer 55-9 having a 4,4,4-)liphenylamine structure or a derivative structure thereof as a repeating unit.
Additive 5 to 5% by weight, containing conductive powder and fluororesin
It is an object of the present invention to solve the above-mentioned problems by using a composition consisting of 45% by weight as an electrode for a secondary battery attached to a conductive grid-like support.

4.4.4-) As a derivative of liphenylamine, 4
．． 4'-(4'-substituted or unsubstituted) triphenylamine and the like are used. These polymers do not polymerize three-dimensionally but linearly, so they have the disadvantage of being slightly soluble in electrolytes. Therefore, it is preferred that the crosslinking agent be added now and polymerized, at least in part sterically and polymerized.

Here, the conductive lattice-like support is one that does not chemically react with electrolytes and active materials such as platinum, titanium, tantalum, etc., and has a potential range of Q ~ + 1.5 V (vaAj/At(J)). It is preferable to be made of a metal that is electrochemically stable. Also, as for the shape, a lattice-like shape such as a lattice shape, a net shape, a lath metal shape, a honeycomb shape, etc. is preferably used.

The conductive powder may be a material that does not react with the electrolyte or active material and is electrochemically stable, such as platinum, acetylene black, or graphite.

Gold, tantalum, etc. are preferred.

Examples of fluororesins include polytetrafluoroethylene or those having a similar chemical structure, such as polytetrafluoroethylene, polytetrafluorochloride, polyvinylidene hexafluoride, and copolymers of tetrafluoroethylene and hexafluoropropylene. etc. are preferable.

In the electrode of the present invention, a polymer having a 4,4', 4'-1J phenylamine structure or a derivative structure thereof as a repeating unit (hereinafter referred to as tritriamine) is used in the composition attached to the conductive lattice-like support. It is not preferable to set the proportion of the phenylamine polymer (referred to as phenylamine polymer) to 55 to 95% by weight because if it is less than 55% by weight, the energy that can be taken out per unit weight of the electrode will be low. Moreover, if the weight exceeds 95 fb, the proportion of the conductive powder or fluororesin powder decreases, the internal resistance of the electrode increases, and the active material tends to fall off from the conductive lattice-like support, so it is unsuitable. .

The additive containing carbon powder and fluororesin powder is added in an amount of 5 to 45% by weight in the composition, and particularly preferably, the carbon powder is added in an amount of 3 to 40% by weight in the composition. It is preferable to determine the composition of the additive so that it accounts for 2 to 10% by weight in the composition.

When the proportion of electrically conductive powder in the composition is less than 3% by weight,
This is not preferable because the internal resistance of the electrode increases, and the triphenylamine polymer may not be fully utilized as an active material, and the energy that can be taken out per unit weight of the electrode decreases. Conversely, in the composition 40
If it exceeds 1% by weight, no increase in the utilization of the triphenylamine polymer can be expected, and the weight of the electrode increases as the proportion of the conductive powder increases, which is not preferable.

Fluororesin powder is generally used as a dispersion in a bath liquid, but in this case, the solid content (
Calculated based on the weight of fluororesin powder). If it is less than 2% by weight, the binding properties of the active material are poor, and repeated charging and discharging causes the active material to fall off from the electrode, resulting in a shortened lifespan. Conversely, 10 weight i
If it exceeds t, although the binding property of the active material increases, since the fluororesin itself is non-conductive, negative effects such as an increase in the internal resistance of the electrode and a decrease in the degree of utilization of the triphenylamine polymer become noticeable, so it is preferable. [Example] Next, the present invention will be described with reference to an example.

Example 1 0.8 t (0.02 gram atomic weight) of metallic potassium,
0.95 t (0.01 mol) of magnesium chloride and tetrahydrofuran were heated to reflux with stirring in a 501 dt-100 volume flask under a nitrogen atmosphere for reaction. After about 1 hour, black powder was produced, confirming the production of metallic magnesium.

Next, 4,4,4-IJ bromotriphenylamine 3.2 P (0,067 mol) was added to the reaction product, and the mixture was heated to reflux with stirring. After about an hour,
It was confirmed that metallic magnesium was completely consumed.

Next, dichlorobis(2,2
-Bipyridine) 10η of nickel was added, stirred, and heated under reflux to smoothly start the polymerization reaction, and a yellowish brown polymer was precipitated. The polymerization reaction was carried out for a total of about 2 hours,
The generated precipitate was poured into ethanol acidified with hydrochloric acid, stirred for 1 hour, and then filtered. After thoroughly washing the filter with ethanol, it was extracted with hot ethanol using a Soxhlet extractor for 12 hours to remove impurities, and after drying, the desired polymer (poly(4,
4,4-triphenylamine) was obtained.

The thus obtained polymer was a yellow powder and was extremely stable without any change even after being left in the air for 2 months. Additionally, thermogravimetric analysis of this polymer was conducted. As a result, it was found that the polymer had extremely high thermal stability without losing weight up to 300°C, and showed a residual weight of about 70% even at a high temperature of 700°C in a nitrogen atmosphere.

In addition, infrared spectrum analysis was performed on the obtained polymer, and the measured infrared absorption spectrum showed that 1270 an-
1, L310crI&-1+ 14807:IFI-1
It was found that it had a strong peak based on the triphenylamine structure at 1590 cm -1 and an absorption of para-substituted benzene near 8203-1. This thing is
This proves that the polymer is composed of regular repeating units and has the following structure.

In addition, elemental analysis of the polymer was performed and the results were as follows: Elemental analysis values of the polymer: Carbon 71.5%, Hydrogen 4.3%, Nitrogen 4.4%.
(Halogen 15.7% This analysis value) C: H: N: Br=18: 12.9: 0
．． 95:0.59, which was close to the theoretical value Css Hat N. Extra 0.9 and 0 for H
．． 59 seems to be the terminal group. The molecular weight could not be determined because this polymer could not be subjected to normal tests. However, reactions of other similar substances and H and Br.

Judging from the number, it seems that 10 to 15 triphenylamines have been polymerized.

The triphenylamine polymer, acetylene black manufactured by Denki Kagaku Kogyo as a conductive powder, and Teflon Dispersion T manufactured by Mitsui Fluorochemicals as a fluororesin powder as a binder, were mixed in the weight ratio shown in the table. death,
A clay-like polymer electrode material composition was obtained by cross-mixing (using a crusher or three rolls).

Next, this polymer electrode material composition was pressed and formed into a sheet shape, and platinum wire gauze was sandwiched between both sides, and the thickness was adjusted to 1 to 2. Vacuum dry for 1. L%+X
,,l OmX IO An electrode with the size of a wing was obtained.

FIG. 1 shows a cyclic portammogram of the electrode of this example in a 1 molar lyticum perchlorate propylene carbonate solution. During the first sweep on the oxidation side, a particularly large current flows, but when the potential sweep is repeated thereafter, there is almost no change in the shape of the cyclic portamogram, and the doping and dedoping reactions of CLQ4'' ions occur stably. Repeated.

Therefore, the electrode of this example can function as an electrode for a secondary battery, and has a lifespan of 200 times.
It can be seen that the above-mentioned polyacetylene also has a long life.

Next, M-like operation K, 40 mX I OimX
O, 6 crane electrodes were created. This electrode was connected in parallel to the IJ lithium electrode via a polypropylene nonwoven fabric parator, and a 1 mol lithium perchlorate propylene carbonate bath solution was used.

FIG. 3 shows the 1OmA constant current constant current charging/waiting state of this battery. The final voltage of charging was set to '(i-4, 1V), and the final voltage of discharging was set to 3.2V.The open circuit voltage after charging was approximately 4V, and the amount of electricity discharged was 23mAh. Even if the PTPA of the present invention is left to stand and then discharged, there is almost no decrease in the amount of discharged electricity.
The electrode is a very good friend compared to polyacetylene etc.

Example 2.3 An electrode was prepared in the same manner as in Example 1 except that the proportions of triphenylamine polymer, conductive powder, and fluororesin powder were changed as shown in the following table.

The discharge test results are shown in FIG. The electrodes were made in the same way except for the changes.

The discharge test results are shown in Figure 2.

Comparative Example 3 The triphenylamine polymer prepared in Example 1 was compression molded using a tablet molding machine for infrared spectrophotometers at a pressure of 8 tOV-H, cut into pieces, and conductive adhesive was attached to one side. agent (trade name: “Electrodac” manufactured by Mattison Company, USA)
Using propylene carbonate as a solvent and lithium perchlorate as a supporting electrolyte, an electrolyte bath solution of 1 solu/l was attached to a platinum wire mesh using a platinum wire mesh to prepare a test piece for measuring electrode characteristics. The cyclic voltamma of the measurement electrode was measured in a nitrogen atmosphere using the L electrode as a reference electrode. The potential sweep speed is l mv4
I made it. As a result, after about 10 sweeps, the interface between the platinum mesh used as a current collector and the present polymer peeled off, making it difficult to perform stable measurements.

Therefore, it was found that the electrode of this comparative example had a short lifespan as an electrode for a secondary battery.

[Effect] As explained above, the present invention provides a polymer 55 having a 4,4',4-triphenylamine structure as a repeating unit.
-95% by weight of conductive powder, 2-40% by weight of conductive powder, and 3-5% by weight of fluororesin powder is attached to a conductive grid-like support. , the effect of obtaining a long-life electrode can be obtained. Furthermore, the amount of electricity that can be extracted per unit weight of triphenylamine polymer is theoretically 798%, which is about 1.8% of the theoretical value of 445 Q/f of conventional polyacetylene.
It's double. Therefore, it has the advantage of being lightweight for a secondary battery of the same capacity.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a cyclic voltamgram of the electrode of Example 1, FIG. 2 is a discharge characteristic diagram of Example and Comparative Example, and FIG. 3 is a charge/discharge characteristic diagram of Example 1.

Claims (1)

[Claims] (1) Polymers 55 to 9 having a 4,4',4''-triphenylamine structure or its derivative structure as a repeating unit
1. A polymer electrode for a secondary battery, characterized in that a composition consisting of 5% by weight and 5 to 45% by weight of an additive containing a conductive powder and a fluororesin powder is adhered to a conductive grid-like support.