JPS58147965A - Positive electrode for nonaqueous electrolyte battery - Google Patents

Abstract

PURPOSE:To improve the wetting between a positive active material and electrolyte, and increase the electric-discharge characteristic at a high current density of a positive electrode especially by using an organic-solvent solution of a polyimide-system resin precursor as a binding agent for the positive electrode. CONSTITUTION:A polyimide-system varnish prepared by dissolving a polyimide-system resin precursor in an organic solvent, is used as a binding agent. After such a binding agent is added to mixture consisting of a positive active material and a conductive agent, an appropriate amount of a diluent is added to the mixture so as to make a paste, and the paste is applied to a current collecting body. Next, the current collecting body coated with the paste, after being dried, is subjected to heat treatment or pressure molding. Here, the above polyimide-system resin precursor indicates a matter which is converted into or synthesized into a polyimide-system resin by the following heat treatment or pressure molding, and a polyimide resin can be given as an example. A polyimide-system varnish prepared by dissolving such a polyimide-system resin precursor in an organic solvent, is used as a binding agent in this invention. Here, the above organic solvent may be any matter that can dissolve the above precursor. Usually, dimethylacetamide, N-methylpyrrolidon or the like is preferred as the above organic solvent.

Description

[Detailed Description of the Invention] This invention relates to a positive electrode for a non-aqueous battery using a pager solvent as an electrolyte, and its purpose is to provide a non-aqueous electrolytic plate battery that can be custom-made with several layers. be.

As a primary battery for non-aqueous electrolyte solution, 10,000 ml of alkaline gold such as lithium or sodium is used for the negative aneurysm.
In fact, sulfides, chlorides, and halogenated carbon compounds are used, and propylene carbonate, γ-butyllactone, 1°2-dimethoxyethane, etc. are used as non-hydromagnetic release agents (some solvents, There are some that use liquids in which terfs salts such as lithium chlorate, lithium aluminum chloride, and lithium fluoroborate are dissolved.1 meter of these waterfalls is 1 castle tm.
It is known that there are many advantages such as high pressure, high density, and low self-reefing. Primary batteries using carbon fluoride or manganese dioxide as specific positive electrode active materials 'a' have been put into practical use. In recent years, there has been a great deal of interest in the secondary benefits of non-aqueous electrolytes. Recently, a non-aqueous electrolyte secondary ridge 1 using a chalcogen compound of a transition metal as a positive electrode active material for secondary
10 was proposed, and some lithium secondary batteries (like Ike) using titanium dioxide as the +E electrode active material were also used.

The positive electrode of the above-mentioned non-aqueous semi-solution Hk stable pond is made by mixing a hypoallergenic agent and a stone agent with the active proboscis a, and using a material such as stainless steel net.
It can be formed by pressure molding into a body (magnetic pole core), or it can be made into a paste by making a paste of a mixture of positive electrode active material, a conductive agent, and a binder, and then applied and dried (□□ □It is constructed by performing pressure molding.

Binders conventionally used in the above-mentioned method using a pasty mixture include polyethylene, polypropylene, polytetrafluoroethylene, and the like.

Such a binder has water repellency and poor compatibility with the electrolyte, so it significantly impedes wetting between the positive electrode active container and the electrolyte, and as a result, the force resistance is particularly high at high currents. 1) There was a problem that the characteristics were not excellent.

This invention has been made to solve these problems. Thus, according to Somei, it is an IE electrode using a non-aqueous electrolyte of heavy oil, which is formed by coating a current collector with a paste containing a positive electrode active material, a conductive agent, and a binder as soil components, and the binder is a binder. There is provided a positive electrode of a non-aqueous solution solution, characterized in that is an organic solvent solution of polyimide thread resin exfoliate a.

The positive electrode of the present invention usually uses a polyimide varnish in which a polyimide resin substance is dissolved in an organic solvent as a binder, and adds this to a mixture of the positive electrode active material a and the rod can agent. It is obtained by adding a diluent to form a paste, applying this paste to the assembly, drying and subjecting it to heat treatment or pressurization type 032.

The polyimide resin @ precursor material of the present invention refers to a substance that can be converted into or synthesized into a polyimide resin by subsequent heat treatment or pressure molding, and may be composed of two or more types. The above polyimide tree! Specific examples of the shield include polyimide resins, and other examples include copolymer resins having a polyimide ring as the main chain, such as polyamide-imide resins, polyamide-imide resins, and polyimide-siloxane co-car chassis resins. . Precursors for polyimide resin include pyromellitic anhydride and diamines, such as
Intermediate polyamide carboxylic acids that are mixtures with diaminodiphenyl ether or pre-complemented thereof are mentioned, and in the case of polyamide-imide resins, there may be mentioned mixtures or precondensates of trimellitic anhydride and diamines, and other polyimides. A mixture of similar constituent monomers or a precondensate thereof can be applied to the f1it resin.

A polyimide varnish prepared by dissolving such a polyimide fruit tree precursor proboscis in an organic solvent is used as the Ni agent of the present invention. OJ for toilet? Generally, dimethylacetamide, N-methylpyrrolidone, etc. are preferred.

Further, the concentration of the precursor in such a varnish is not particularly limited, but is usually about 20 to 30 %.

Such a polyimide varnish (binding ~) is mixed with a positive electrode active material and a conductive agent used in the field, and an appropriate diluent is added thereto to form a paste. Usually, water is suitably used as the diluent, and in addition to this, a bath agent that is compatible with the organic solution and the M phase can be used. Further, a small amount of polyvinyl alcohol 7 may be added as a viscosity modifier.

The mixed paste described above is applied to the assembly according to a conventional method, dried, and then subjected to heat treatment or pressure molding at a temperature of 200 to 300°C. As the solvent evaporates, the polyimide resin undergoes polycondensation and turns into a polyimide resin (ψ) and hardens, yielding the non-aqueous positive electrode of this invention. It will be done.

The positive electrode obtained in this way has a large mechanical cliff and good compatibility with the 1M electrolyte, so the impregnation rate is better and it is better than the conventional positive electrode. ! It was found that stable magnetization characteristics were exhibited because the voltage was +&1+<, and the increase in internal resistance due to discharge was small. In particular, it exhibits excellent radiation characteristics for Akane rate release, and provides high rate release.

Hereinafter, this invention will be explained in more detail with reference to Examples.

Example 1 Seigo active proboscis made by heat-treating commercially available manganese dioxide in air
Part of powder 90, Acetylene black 6 as S plant agent
Approximately 5110 tons of water was added to 2 parts of a composition prepared by mixing 4 parts of polyimide varnish and 1 part of polyimide varnish as a binder to form a paste. The polyimide varnish used was an organic solvent solution containing about 23% of polyimide resin H1I-substance (Trenice; four product names from Toshishima).

The present invention can be achieved by applying the above paste to a stainless steel net, drying it, shaping it into a predetermined shape, and then heat-treating it at about 25 nC in a summer atmosphere for the purpose of removing moisture and binding. I got my admiration.

Example 2 Commercially available manganese dimide was added to '4! , 90 parts of positive electrode active material powder heat-treated in air, 6fi acetylene black as overprint, :it part, 3 parts of polyimide varnish (same as Example 1), and PVA powder (polyvinyl alcohol)
A composition made by combining a part of 1 city with i+, 2 KLi, and about 500 ml of water.
In addition, it is made into a paste form, this paste is placed on a stainless steel net made by Azuma Kotai, and after drying, it is punched out into a predetermined shape and molded, and then subjected to air treatment at 250C for 1 hour to form a PV.
A was decomposed and then heat treated at about 200C under a summer atmosphere to obtain the 11:1 pole of this light.

(7) This is what we provide.

The positive electrode obtained in the above example, the negative electrode pressed onto a negative electrode cap punched from a metal lithium plate, and 1% in an organic mixed solvent of propylene carbonate and 1,2-dimethoxyethane.
Using electrolytes aA (Example 1) and B (Example 2) which were composed of an electrolytic solution in which about a molar amount of lithium perchlorate was mixed, the lKΩ constant negative release characteristics at 20°C were investigated. In addition, as a comparative example, a similar conventional city pond C using polyethylene as a storage material was also investigated in the same manner.

These results are shown in FIG.
From the values, it can be seen that the 4 batteries A and 13 have improved 1ltp characteristics compared to the conventional battery C.

As stated above, the non-aqueous electrolyte of this invention'@/ll
The positive electrode of z is characterized by using an organic bath agent solution of polyimide thread resin MiJ compound as a binding agent. The rate increases, and the increase in internal resistance that accompanies the progress of release is suppressed. Therefore, conventional r4ri1! We proposed a pond with good commercial volume and growth characteristics compared to the non-water market (8)

[Brief explanation of drawings]

FIG. 1 is a graph showing an example of a custom-made non-aqueous solution Makiike pond using the present invention together with a comparative example.

Claims (1)

[Claims] 1. A positive electrode for a non-aqueous electrolyte battery that is formed by applying a paste containing a positive electrode active material, a conductive filler, and a binder as main components to a current collector, and the stone agent is a polyimide resin @ A positive electrode for a non-aqueous electrolyte battery, characterized in that it is an organic solvent solution of a precursor substance.