JPS60109182A - Secondary battery - Google Patents

Abstract

PURPOSE:To suppress dendritic growth of lithium caused by repeating of charge- discharge and provide a lithium battery having good charge-discharge efficiency and good performance for a long time by using transition metal oxide or transition metal chalcogen compound as a positive active material, and lithium hexafluoride or lithium trifluoromethanesulfonate solution as nonaqueous electrolyte. CONSTITUTION:TiO2, Cr3O8, V2O5, V6O13, MnO2, LiCoO2, CuO, or MoO3 is used as transition metal oxide for positive active material 3. TiS2, VSe2, Cr0.5, V0.5S2, CuCo2S4, FeS NbSe3, or MoS3 is used as transition metal chalcogen. Lithium, lithium alloy, or polymer sinter containing lithium is used as a negative active material. Lithium hexafluoride and/or lithium trifluoromethanesulfonate is used as lithium salt of nonaqueous solution. A mixed solvent of 3-substitution-2- oxazolidinone and cyclic ether is used as a solvent, and its volume ratio is 1:9- 9:1, preferably 2:8-8:2. In this ratio, ion conductivity is high and charge-discharge efficiency of battery is good.

Description

[Detailed Description of the Invention] The present invention relates to an organic electrolyte secondary battery. 3. In recent years, the development of electronic technology including LSI has been remarkable, and various devices have become dramatically smaller!1.1.! , light 11 (is planned, l'l'FJ energy density is q', 1,
Moreover, the demand for lithium batteries with a discharge rate of 1aIL is increasing to a high degree.However, the lithium batteries that have been put into practical use are primary batteries, and secondary batteries have not yet been put to practical use.

One of the most important problems with secondary batteries is that the lithium used as the negative electrode active material grows in a resin-like manner on the negative electrode surface during charging, causing an internal short circuit, resulting in extremely short charging and discharging cycles. That's important.

The present inventors have conducted extensive research to solve these problems, and as a result have arrived at the present invention (4). That is, the present invention provides a positive electrode active material selected from the group consisting of transition metal oxides and O-transition metal chalcogen compounds, and lithium.

A negative electrode active material selected from the group consisting of lithium alloys and fired lithium-containing polymers, lithium phosphorus hexafluoride and/or lithium trifluoromecunesulfonate in a mixed solvent of 3-substituted-2-oxazolidinone and cyclic ether. This is a secondary battery composed of a non-aqueous electrolyte consisting of a solution.

Examples of the transition metal in the transition metal oxide and/or transition metal chalcogen compound in the positive electrode active material include titanium, vanadium, chromium, manganese, cobalt, copper, iron, niobium, and molybdenum. Saponified transition metals include TiO2゜Cr30s, V+Oi,
ViOu, MnO+, LiCo0+, Cub,
Examples include Mho:t. Further, as a transition metal chalcocene compound, TiS2. VSe+, Cro,!
5%ySl, CuCo25+, FcS, NbS
c, +.

MO3I etc. can be opened.

The upper electrode active material is generally a grown culm (used as a body, grown),
(1, J method is to use positive electrode active material powder or 1
1" polar active material powder and synthetic resin powder (powder of Teflon, polyethylene, polystyrene, etc.) 6>"l'! An example of this method is to pressurize and sinter the material inside.

In the negative (moe active material), lithium, lithium alloy (alloy mainly composed of lithium, such as lithium-aluminum alloy) can have a foil-like, plate-like, or rod-like shape, but an ffi-like shape is preferable. In addition, as lithium-containing polymer fired bodies, examples of polymers such as polyacrylohexatolyl, polyvinyl chloride, polyhynylidene chloride, polyarylacetylene'l (polyphenylchloroacetylene, etc.), polyimide J:rl (polyoxydiphenylene, Comelitimide, polyhenzoxasolimide.

Polyimidazopyrroloneimide, polyamideimide.

polyhydrazideimide, etc.), one package of polyamide, polysemicarbazide, polybenzoxazinone, etc.) Polymer sintered bodies with a conjugated structure obtained by sintering polysemicarbazide, polybenzoxadinone, containing lithium (e.g. No. 58-28974 (Specification 5/J1).

As a method for producing a polymer fired body, there is usually a method of heating and heat-treating the polymer under an inert atmosphere of δ1m (□), the heating temperature is usually 300″C or higher, preferably 5 U O- 15 (10°°C.

The shape of the polymer sintered body subjected to i4J in this manner is usually film-like, woven fabric-like, fibrous-like, thin-plate-like, powder-like, or the like.

When incorporating lithium into the polymer fired body, the amount of lithium in the fired body is usually 0.1 per 100g of the fired body.
~40g, preferably 02-18g.

Methods for incorporating lithium into a fired polymer body include methods for incorporating lithium into a fired polymer body in the form of a film or woven fabric, and a method for incorporating lithium into a fired polymer body in the form of a film or fabric, and a method for incorporating lithium into a fired polymer body in the form of a powder and a synthetic resin in the form of a powder (Teflon, polyethylene, polystyrene, etc.). ) or a pinch of petroleum or petroleum dry distillate, such as tar, are mixed, kneaded, and then heat-molded to impregnate lithium.

Specifically, methods for incorporating lithium into the fired polymer body include electrochemical methods, chemical methods, and physical methods. As the electrochemical fishing force lJ1, there is a method in which the non-aqueous organic electrolysis 11k of lithium salt is made white by using a polymer fired body as a positive electrode and lithium salt as a negative electrode, and current is passed between +E and the negative electrode.

As a chemical method, the fired polymer body is immersed in an organic solvent solution (concentration usually 5 to 50% by volume) of an aliphatic hydrocarbon such as alkyllithium or aryllithium, an ether such as tetrahydrofuran, etc. Another method is impregnation.

The soaking or impregnating temperature is usually 5 to 30°C for 1 hour.
~50 hours.

Further, as a physical method, there is a method of exposing the fired polymer body to lithium vapor. Preferred among these methods are electrochemical methods and chemical methods.

A method for producing a polymer fired body and a method for incorporating lithium into the fired body are described in Japanese Patent Application No. 58-28974.

In the well water electrolyte, the 3-substituted-2-oxazolidinone has the general formula (wherein R1, R2, Ri, and R1 are hydrogen atoms, alkyl groups, cycloalkyl groups, or aryl groups.
i is an alkyl group, a cycloalkyl group or an aryl group. ) can be mentioned. .

In the general formula (1), the alkyl group of R1, R2, R3, and Ri is usually a straight chain or a straight chain having 1 to 10 carbon atoms.

Branched alkyl groups such as methyl group, ethyl group, normal or isopropyl group, normal or isobutyl group,
Examples include decyl group. Examples of the cycloargyl group include cyclohegycyl, (, methylcyclohegycyl, etc.).Arylno, (such as phenyl J, C,
P-methylphenyl, 1 is opened. R1,I
Among h, R1, and Rh, preferred are water g.2 atoms, methyl group, and ethyl group. R5 alkyl group, cycloalkyl group (and arylno1 (as R1, Ih
, Rh, and the same groups as the alkyl group, cycloalkyl group, and aryl group of Rh. Among Rh, preferably methyl group and ethyl group, (Δ・)ru1, general formula (
1) As the 3-substituted-2-o.)-sacyridinone, 3-argyl-2-g-t-sacyridinone/(3
-Methyl-2-oni)-ri°solidinone, 3-methyl-
4-Methyl-2-N-1-lysilidinone, 3-methyl-5-methyl-2-xasolydinone, 3-ethyl-
2-O1-1Nasoricinone, 3-ethyl-4-methyl-2-oxazolidinone, 3-butyl-2-oxazolidinone)-3-cycloalkyl-2-oxazolidinone (3-cyclohexyl-2-oxazolidinone, :3 Nishiku 1j
hexyl-4-methyl-2-oxazolidinone) and 3-aryl-2-oxazolidinone (3-phenyl-2-oxazolicinone, 3-phenyl-4-methyl-2-oxazolidinone, etc.), and two types thereof A mixture of the following is mentioned.

Among these, preferred are 3-methyl-2-oxazolidinone and 23-ethyl-2-oxazolidinone.

: tonecil-5-meJ-ru-2-oxasolicinone and 3-ethyl-5-methyl-2-oxazo-1-nocinone.

As a cyclic ether in a non-aqueous electrolyte, 5'Ml
Needle (tetrahydrofuran), substituted (alkyl, alkoxy)tetrahydrofuran such as 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, 2-ethyltetrahydrofuran, 22'-dimethyltetrahydrofuran.

(2-methoxytetrahydrofuran, 25-dimethoxytetrahydrofuran, J3-dioxolane, etc.) 6-membered ring ethers (1,4-dioxane, pyran, dihydropyran, tetrahydropyran, etc.) and mixtures of these two. .

Among these, IIf or J-neetil having a penta-ring.

Particularly preferred are tetrahydrofuran, 2-methyltetrahydrofuran, 2-ethyltetrahyfuran and 25-dinotyltetrahydrofuran.

The volume of the mixed solvent of the 3-substituted 2-oxasolidinone and the gelatinous ether is usually 1:9 to 1:1, preferably 2:8 to 8:2. - The ionic conductivity is high in the ratio range shown below, and the charge/discharge efficiency is low.

Lithium phosphorous hexafluoride and/or lithium trifluoromethanesulfonate are used as the lithium salt of the J1 aqueous electrolyte.

The concentration of lithium phosphorous hexafluoride and/or lithium trifluoromethanesulfonate is! LM sound f? ; Normally 01 to 5 mol/e, preferably ()5 to 5 mol/e in the solvent 11
It is 3 mol/e.

The method for preparing the electrolytic solution is not particularly limited, as long as the above-mentioned lithium Ji,a is dissolved in an organic solvent.An example of the secondary battery of the present invention will be explained with reference to FIG. In Figure 1, (1) is a positive electrode can (positive electrode current collector), (2) is a metal net for current collection, (3) is a positive electrode active material, (4) is a separator,
(5) is liquid absorbing material, (6) is L-shaped gasket, (7)
is a negative electrode active material, (8) is a negative electrode can, and (9) is a metal net for current collection. A current collecting metal net 1-i21 is placed on the bottom of the positive electrode can (1), and a molded positive electrode active material (3) is crimped onto it. Alternatively, a mesh-shaped separator (made of polyethylene, etc.) (4) is placed, a synthetic resin liquid-absorbing material (5) is placed on the separator (4), and the non-aqueous electrolyte of the present invention is injected, followed by an L-shaped separator (4). A shaped caskerat (6) is inserted along the wall of the positive electrode can (1).On the other hand, a negative electrode active material (7) is inserted into the negative electrode can (1).
i ('Qmi' to 8i, after interposing Fi Kawayo Net +91 and adhering to it, the liquid-absorbing material containing and retaining the non-aqueous electrolyte (5) of the present invention) was applied for 1 generation. Place the positive electrode can (1)
Bend the open end part of 1-1 inward.

The secondary battery of the present invention suppresses dendritic growth of lithium on the surface of the negative electrode due to repeated charging and discharging, and has excellent charging and discharging efficiency.
The battery has sufficient battery characteristics over a long period of time.

The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto.
5.Polyethylene powder was mixed and press-formed 11;14 to produce a positive electrode active material molded body made of stainless steel.
Nickel net 1 placed on the bottom of pole/111, pressure on top,
i'1 (/ta51 then 1) IJ record 7 (2 bodies) After placing a polypropylene separator on the second, 3-methyl-
2-Ox→)゛Equivalent volume of solidinone and 2-methyltetrahydrofuran'+'C'(]a i'i 1 mol/
Inject well water electrolyte in which sodium hexafluoride is dissolved at a concentration of r, and cassette is jlf! There were people. After that, place the stainless steel L/S negative pj bow 11 covered with lithium foil on the separator 11. 3. As a reference comparative example, a battery was prepared by bending the end portion of the bow 11 inward and sealing the sealing portion hermetically. 1 mol/1 in an equal volume mixed solvent of and tetrahydrofuran! Batteries were made in the same manner using an electrolyte composition in which lithium oxide was dissolved in hypersalt at a concentration of A charge/discharge test was conducted in which the battery was discharged at a constant current of 1 mA until the depth of discharge reached 130%, and then charged to that capacity.The results are shown in Table 1.

Example 2 Polymer sintered body 101i' obtained by firing 2-chloro-1-phenylacetylene powder at 800°C for 2.5 hours and polyethylene powder 1. were mixed and kneaded well. , Fri 71; 17 and 300ky/cr
A sheet with a thickness of 1 mm was obtained under a pressure of rrG. This sheet was cut into a disc shape with a diameter of ] cm, and this was crimped onto a stainless steel tube as a positive electrode, and a lithium foil was used as a negative electrode. Insert both poles and make W:, l'J. then 0.5
mA O,) constant current for 30 hours, resulting in 4
The polymer sintered disk-like sort containing mg of Litiuno is 11, jI) λL 7',: .

In Example 1, 1- instead of ``tl''l
11 A polymer containing lithium; a lithium-containing circular sheet was used, and the other operations were the same. [A battery was made and a similar charge/discharge test was performed.1 As a result, 90 times. [Il with good reversibility up to -1
'14' gender was 8j.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the battery. (3) Cathode active material (4)・Se/Maleku (5)
Liquid-absorbing material (7) Negative electrode active material Fuekou Zu Mie = Continued by Nichi Tadashi Demand Showa algae 1JFebruary 2'71-1 1, $1'1 Indication 1982 Special revised application No. 217397 2, Invention Name secondary battery 3, relationship with the person making the amendment 1J Kushii'1 Q'r = T applicant's residence 1, 11, Kunogi-cho, Higashiyama-ku, Kyoto City 5, number of inventions increased by the amendment 6. NtitiE's customer 1111 detailed explanation of the invention (11''j7
, Contents of the amendment As shown in the attached sheet (1) Akira nari'i l: page j, between lines 9 and 10, [Example 3 manganese dioxide, acetylene black onihidefronmu] wood was mixed. , molded body C=-it produced by pressure molding
: Used as an active material, 3:1 of 3-methyl-2-41 lysolidinone and 2-methyl hydride and J nonone.
Dissolve lithium phosphorus hexafluoride in a volumetric mixed solvent at a concentration of 12 mol/1! , using Shino as J1 hydroelectric h7 liquid,
Other than that, a battery was produced in the same manner as in Example 1. Charging/discharging test 4 was performed by discharging at a constant current of 'l m/l until the depth of discharge reached 20%, and then charging that capacity at the same current.
It went up to 0-1 Neukle. 1′ζ1, Song showed good charging and discharging as shown in Table 2, and the light 41 of tent trie 1 on the lithium surface.
was not seen. Example 4 1:2 ff1112 combination of 3-methyl-2-A gyrizolidinone and 2゜5-dimethylteI-rahydrofuran)? 1
12 times, g(+) fliHAr lithium phosphorus hexafluoride dissolved in 4J1 water? Li li' / 't
Used as Ik, and otherwise 1 and 1 and ■ as in Example 3.
A fTh pond was successfully constructed. A constant current of 1 mA increases the depth of discharge to 10%. A photodischarge test was conducted in which the IC was discharged and its capacity was charged with the same flow rate up to 150 cycles. The results obtained are good as shown in Table-3! It showed lf% charge/discharge, and no generation of An1-light on the lithium surface was observed. Insert.

Claims (1)

[Claims] 1. A positive electrode active material selected from the group consisting of transition metal oxides and O (transition metal chalcogen compounds; and a negative electrode active material γ' selected from the group consisting of lithium, lithium alloys, and lithium-containing J polymer fired bodies) ; a well water electrolyte consisting of lithium phosphorus hexafluoride and/or lithium trifluoromethanesulfonate dissolved in a mixed solvent of 3-substituted-2-oxazolidinone and cyclic ether; battery.