JP2004111229A - Polymer electrolyte support body and lithium secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a short-circuiting tends to occur due to generation of metal dendrite when lithium metal is used for a negative electrode, since a gelatinous polymer electrolyte is inferior in film intensity and film formability, though higher in ion conductivity, compared with a solid electrolyte. <P>SOLUTION: By utilizing an organic fiber coated with an inorganic matter as a component member, a polymer electrolyte support body is obtained with flexibility and heat resistance, easy to handle, with improved ion conductivity of a polymer electrolyte, and with necessary intensity secured even with the polymer electrolyte getting fluid at a high temperature. Further, a lithium secondary battery of high safety is obtained with the use of the polymer electrolyte. <P>COPYRIGHT: (C)2004,JPO

Description

【００４７】
実施例１〜３と比較例１の対比から、同じ不織布を用いても、その表面に無機物の粒子が付着していれば、イオン伝導度が向上すると共に、ショート温度も大きく上昇することが判る。また、引張り強度も若干向上することが判る。とくに実施例３から、Ｌｉ_２Ｏ−Ａｌ_２Ｏ_３−ＳｉＯ_２からなるガラスの粒子を用いれば、イオン伝導度が大きく向上することが判る。
【００４８】
また、実施例１〜３と比較例２の対比から、有機繊維を構成部材としないポリマー電解質支持体では、引張り強度が大きく低下し、巻回型電池に不向きであることが判る。
【００４９】
【発明の効果】
以上の説明から明らかなように、この発明によれば、無機物で被覆した有機繊維を構成部材とするので、柔軟性および耐熱性があり、取り扱いが容易で、ポリマー電解質のイオン伝導度を向上させることができ、さらに高温時にポリマー電解質が流動的となっても、必要な強度を確保できるポリマー電解質支持体を提供することができる。さらには、このポリマー電解質を用いた安全性の高いリチウム二次電池を提供することができる。
【図面の簡単な説明】
【図１】実施例および比較例で耐ショート性の測定に用いた装置を示す図である
【符号の説明】
１　ポリマー電解質
２　ＳＵＳ円柱
３　バネ
４　耐熱絶縁板
５　抵抗測定器[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polymer electrolyte support for use in a lithium secondary battery. Further, the present invention relates to a lithium secondary battery using the same.
[0002]
[Prior art]
2. Description of the Related Art In recent years, portable electronic devices such as a camera-integrated VTR, a CD player, a laptop computer, and a portable telephone have become widespread, and the size and weight of these electronic devices have been reduced. Among them, demands for performance improvement for batteries are increasing, and expectations for secondary batteries are particularly high from an economic viewpoint.
[0003]
Lithium secondary batteries are attracting attention as battery systems that meet the above requirements, and are being actively studied. However, in a lithium secondary battery, a highly corrosive salt such as lithium hexafluorophosphate or lithium borofluoride is dissolved in an organic solvent, and this is used as a liquid electrolyte. There was a problem. In order to solve this problem, those using a gel electrolyte or a solid electrolyte have been developed.
[0004]
The ionic conductivity of a general polymer electrolyte is about 10 ⁻⁵ S / cm in a low temperature range of about room temperature, and the value is two orders of magnitude lower than that of a liquid ion conductive substance. However, it is known that when the polymer electrolyte becomes gel-like, its ionic conductivity increases. However, a gel-like polymer electrolyte cannot be handled as a completely solid, has poor film strength and film-forming properties, and when incorporated into a battery, tends to cause a short circuit and seals like a liquid electrolyte. There was a problem that it was difficult to stop. In particular, regarding the short circuit, when lithium metal is used for the negative electrode, a metal dendrite is generated, so that there is a problem that the possibility of the occurrence increases.
[0005]
In order to solve these problems, a technique for improving the strength, stability and ionic conductivity of a polymer electrolyte by adding alumina particles having a particle size of 5 μm or less is known (for example, see Patent Document 1). . In addition, a technique has been proposed in which a nonwoven fabric made of ceramic short fibers such as potassium titanate is used as a separator (for example, see Patent Document 2). In addition, a separator made of a nonwoven fabric in which a synthetic pulp of polyethylene, a polypropylene-polyethylene composite fiber, and a glass fiber are mixed has been proposed (for example, see Patent Document 3).
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 10-334731 [Patent Document 2]
JP 9-92255 A [Patent Document 3]
JP-A-59-180966
[Problems to be solved by the invention]
However, in the technology described in Patent Document 1, simply adding alumina particles to the polymer electrolyte causes the alumina particles to be fluid when the polymer electrolyte is heated and fluidized, so that the strength and stability of the polymer electrolyte are increased. It was difficult to improve. In addition, when particles are added, they are dispersed in the polymer electrolyte, so that the ion conductivity is improved at the interface of the particles, but from the macroscopic viewpoint of the polymer electrolyte, the ion conductivity due to the addition of alumina particles is increased. The degree of improvement was limited.
[0008]
In the technique described in Patent Document 2, the ionic conductivity is improved at the interface between the short ceramic fibers, so that the ionic conductivity can be expected to be improved in that the shape is more continuous than the alumina particles. There is a problem that the strength of the separator tends to be insufficient, and the separator cannot be used for a wound type battery.
[0009]
Further, according to the technology described in Patent Document 3, when the proportion of glass fiber is large, it is difficult to secure necessary strength, and it is difficult to produce a thin separator. On the other hand, if the content of glass fibers or ceramic fibers is reduced to ensure strength, the number of components that contribute to the improvement in ionic conductivity decreases, and the improvement cannot be expected.
[0010]
The present invention has been made in view of such a problem existing in the related art. The purpose is to use organic fiber coated with inorganic material as a constituent member, which has flexibility and heat resistance, is easy to handle, can improve the ionic conductivity of the polymer electrolyte, and has a high temperature. An object of the present invention is to provide a polymer electrolyte support that can secure necessary strength even when the polymer electrolyte becomes fluid at times. Another object of the present invention is to provide a highly safe lithium secondary battery using the polymer electrolyte.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the polymer electrolyte support according to the first aspect of the present invention contains organic fibers coated with an inorganic substance.
[0012]
The polymer electrolyte support according to the second aspect of the present invention is the one according to the first aspect, wherein the polymer electrolyte support contains inorganic fibers.
[0013]
The polymer electrolyte support of the invention according to claim 3 is the polymer electrolyte support according to claim 1 or 2, wherein the inorganic substance or the inorganic fiber is lithium, sodium, magnesium, calcium, barium, boron, aluminum, silicon, phosphorus, titanium, At least one selected from the group consisting of vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, selenium, yttrium, zirconium, niobium, molybdenum, silver, indium, tin, antimony and tellurium Contains oxides, sulfides, nitrides or iodides of the following elements:
[0014]
The polymer electrolyte support of the invention according to claim 4 is the polymer electrolyte support according to any one of claims 1 to 3, wherein the inorganic substance or the inorganic fiber is a glass containing at least lithium, aluminum, and silicon. .
[0015]
A polymer electrolyte support according to a fifth aspect of the present invention is the polymer electrolyte support according to any one of the first to fourth aspects, wherein the content of the organic fibers coated with the inorganic substance is 30% by mass or more.
[0016]
The polymer electrolyte support of the invention according to claim 6 is the organic electrolyte coated with an inorganic material based on the mass of the entire polymer electrolyte including the polymer electrolyte support in the invention according to any one of claims 1 to 5. The total content of fibers and inorganic fibers is 1 to 50% by mass.
[0017]
The polymer electrolyte support of the invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the adhesion rate of the inorganic substance is 1 based on the mass of the organic fiber before being coated with the inorganic substance. ~ 50% by mass.
[0018]
The polymer electrolyte support of the invention according to claim 8 is the polymer electrolyte support according to any one of claims 1 to 7, wherein the inorganic substance is in the form of particles.
[0019]
According to a ninth aspect of the present invention, in the polymer electrolyte support according to the eighth aspect, the average particle diameter of the inorganic substance is 1 to 200 nm.
[0020]
A lithium secondary battery according to a tenth aspect of the present invention uses the polymer electrolyte support according to any one of the first to ninth aspects.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0022]
The polymer electrolyte support contains organic fibers coated with an inorganic substance such as silica (SiO ₂ ) particles or a lithium ion conductor as constituent members. Since organic fibers are flexible and can fuse their contacts only by heating, a woven or non-woven fabric containing the same is preferable as a polymer electrolyte support having elasticity and excellent shape retention. With characteristics. However, on the other hand, organic fibers cannot increase the ionic conductivity at the interface, and because they become fluid in a high-temperature environment and cannot maintain their shape, these points are disliked and conventional lithium secondary batteries have It has not been used for polymer electrolyte supports. Further, the inorganic substance has a high heat resistance and has a preferable property as a polymer electrolyte and its support, which can increase ionic conductivity at the interface, but has a problem of lacking flexibility. Then, the surface of the organic fiber is coated with an inorganic substance so that each of the excellent properties is exhibited and the mutual disadvantages are complemented. When this polymer electrolyte support is used, the inorganic substance hinders fluidization of the organic fibers even at high temperatures, so that it is possible to effectively increase the ionic conductivity of the polymer electrolyte while securing the safety of the lithium secondary battery. it can.
[0023]
As inorganic substances, lithium, sodium, magnesium, calcium, barium, boron, aluminum, silicon, phosphorus, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, selenium, yttrium, Examples include oxides, sulfides, nitrides, or iodides of at least one element selected from the group consisting of zirconium, niobium, molybdenum, silver, indium, tin, antimony, and tellurium.
[0024]
Further, the inorganic substance may be a glassy substance containing the above element as a component. This glass includes a lithium ion conductor such as Li ₄ SiO ₄ —Li ₃ PO ₄ , Li ₂ O—SiO ₂ —ZrO ₂ , Li ₂ O—LiCl—B ₂ O ₃ , Li ₂ S—GeS ₂ , and LiI— Li ₂ S—P ₂ S ₅ , LiI—Li ₂ S—B ₂ S ₃ , Li ₃ PO ₄ —Li ₂ S—SiS ₂ , LiI, Li ₃ N, LIICON, lithium phosphate derivative and the like are included. In the lithium ion conductor, lithium ions can move inside. Therefore, if this is used for the polymer electrolyte support, the internal resistance of the lithium secondary battery can be reduced. The lithium content in the lithium ion conductor is preferably 5% by mass to 30% by mass. When the lithium content is less than 5% by mass, the ionic conductivity decreases. On the other hand, if it exceeds 30% by mass, the ionic conductivity may be reduced or the glass may not be vitrified.
[0025]
It is preferable that the glass contains silica and aluminum oxide as composition components. In _particular, the glass consisting of _{Li 2 O-Al 2 O 3} -SiO 2 being preferred. Silica and aluminum oxide are chemically stable in a lithium secondary battery, have good hydrophilic properties, and are commercially available at a low cost. If a glass made of Li ₂ O—Al ₂ O ₃ —SiO ₂ is used, there is almost no decrease in ionic conductivity even in a low temperature range of about room temperature, so that the ionic conductivity of the polymer electrolyte can be increased regardless of use conditions. .
[0026]
The content of the organic fibers coated with the inorganic substance is preferably 30% by mass or more based on the mass of the polymer electrolyte support. If the content is less than 30% by weight, the strength of the polymer electrolyte tends to be insufficient.
[0027]
For the polymer electrolyte support, inorganic fibers may be used together with organic fibers coated with an inorganic substance. The inorganic fiber can improve the ionic conductivity of the polymer electrolyte similarly to the inorganic material. The type of the inorganic fiber is not particularly limited, but a glass fiber, particularly a glass fiber made of Li ₂ O—Al ₂ O ₃ —SiO ₂ is preferable. Since the inorganic fibers need to be uniformly mixed with the organic fibers coated with the inorganic substance, the inorganic fibers preferably have an average diameter and an average length equivalent to those of the organic fibers.
[0028]
When the organic fiber and the inorganic fiber coated with the inorganic material are used in combination, the total content of the organic fiber and the inorganic fiber coated with the inorganic material in the polymer electrolyte support is based on the mass of the entire polymer electrolyte including the polymer electrolyte support. Preferably it is 1 to 50% by mass. When the content is less than 1% by mass, the improvement of the ionic conductivity of the polymer electrolyte by the inorganic substance or the inorganic fiber does not appear. On the other hand, if it exceeds 50% by mass, the content of components other than the polymer electrolyte support, ie, the solid electrolyte or the gel electrolyte, becomes relatively low, and the polymer electrolyte support becomes the main player of ion conduction, The decrease in the ionic conductivity of the electrolyte becomes significant.
[0029]
When a polymer electrolyte support is produced by using an organic fiber and an inorganic fiber coated with an inorganic material in combination, the method is not particularly limited. After adhering the inorganic substance to the organic fiber, it may be mixed with the inorganic fiber, papermaking may be performed, or the organic fiber and the inorganic fiber may be mixed, paper-formed, heat-molded, and then the inorganic substance is applied to the nonwoven fabric. Is also good. In particular, according to the latter method, a polymer electrolyte support having high strength and uniformly attached inorganic fibers can be easily prepared.
[0030]
When the organic fibers are coated with an inorganic substance, the adhesion rate of the inorganic substance is preferably 1 to 50% by mass, based on the mass of the organic fibers before coating on the polymer electrolyte support. When the adhesion rate is less than 1% by mass, only a part of the surface of the organic fiber is covered with the inorganic substance, and it is difficult to efficiently improve the ionic conductivity of the polymer electrolyte. In addition, the fluidization of the organic fibers cannot be prevented at high temperatures, so that the safety of the lithium secondary battery using the organic fibers is reduced. On the other hand, if it exceeds 50% by weight, individual voids inside the polymer electrolyte solution support become small and the porosity also becomes small, so that the gel electrolyte or the solid electrolyte becomes difficult to spread, and the internal resistance of the lithium secondary battery becomes low. Will be expensive.
[0031]
As a method of coating the organic fiber with an inorganic substance, for example, a wet method such as a sol-gel method or a precipitation method, a general thin film forming method such as a CVD method, a sputtering method or a vapor deposition method may be used, but the inorganic particles are dispersed. A method of applying the solution or slurry to a nonwoven fabric of an organic fiber or a mixed nonwoven fabric of an organic fiber and an inorganic fiber using a solution or a slurry is preferable because it is simple and inexpensive. When applying a solution or slurry in which particles are dispersed, an adhesive such as polyvinyl alcohol and carboxymethyl cellulose, or an emulsion of polyethylene or polypropylene is used in the solution or slurry to increase the adhesion between the inorganic particles and the organic fibers. Etc. may be added. The adhesive may be thinly applied after the inorganic particles are applied.
[0032]
The inorganic particles preferably have an average particle size (primary particle size) of 1 to 200 nm, more preferably 5 to 100 nm. When the average particle diameter is less than 1 nm, the particles are easily aggregated, so that it is difficult to uniformly disperse them in a solution, and the particles cannot adhere to the organic fibers or the secondary aggregated particles adhere as they are. As a result, the flexibility of the polymer electrolyte support decreases, and the polymer electrolyte support cannot be used for a wound type battery, or an unexpected ion conduction path is formed due to secondary aggregation, and ion conduction at a particle interface is not efficiently performed. On the other hand, when it exceeds 200 nm, irregularities are formed on the surface of the polymer electrolyte solution support, the contact with the electrodes becomes uneven, and the internal resistance of the lithium secondary battery increases.
[0033]
The type and shape of the organic fiber are not particularly limited, and examples thereof include a polyamide fiber and a polyolefin-based fiber. Further, a core-sheath having an average diameter of 1 to 20 μm and an average length of 0.1 to 20 mm is preferable, and further, a core-sheath comprising a heat-resistant core such as polypropylene and a sheath having relatively low heat resistance such as polyethylene. Composite fibers are preferred. After the organic fibers are formed into a nonwoven fabric, a surface treatment such as corona discharge or plasma discharge may be performed.
[0034]
The method of impregnating the polymer electrolyte support with the gel electrolyte or distributing the solid electrolyte is not particularly limited. A known means may be used as it is. The type of the solid electrolyte is not particularly limited, and examples thereof include an organic polymer compound such as a polyether compound. Examples of the polyether compound include polyethylene oxide, polypropylene oxide, polyoxymethylene, and derivatives thereof. The molecular weight of these organic polymer compounds is not particularly limited as long as it can be used as a solid electrolyte, but the molecular weight is 100,000 or more, preferably 500,000 to 5,000,000, more preferably 1,000,000 to 400,000. It is about ten thousand. Further, the type of lithium electrolyte salt contained in the solid electrolyte is not particularly limited, and an alkali metal salt such as LiN (CF ₃ SO ₂ ) ₂ , LiCF ₃ SO ₃ , LiPF ₆ , LiBF ₄ or LiClO ₄ is used. Is exemplified.
[0035]
The polymer electrolyte produced by the above means is formed into a thin film before being incorporated in a lithium secondary battery. The forming method is not particularly limited. For example, a method of sandwiching between release films and pressing at about 60 to 100 ° C. may be mentioned. Known means may be used for incorporation into the lithium secondary battery.
[0036]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
[0037]
(Example 1)
First, a nonwoven fabric is manufactured using organic fibers. A nonwoven fabric having a basis weight of 10 g / m ² and a thickness of 20 μm was prepared by a papermaking method using a core-sheath composite fiber having a core of polypropylene and a sheath of polyethylene and having a diameter of 12 μm.
Subsequently, inorganic particles were attached to the nonwoven fabric. Silica (vitreous primary particle diameter 20 nm) was used for the particles. The particles were mixed in 2-propanol, stirred at 6,000 to 9,000 rpm for 10 minutes using a homogenizer (manufactured by Omni), and then pulverized by a microbead mill (manufactured by WAB). This dispersion was placed in an immersion tank, and the above-mentioned nonwoven fabric was immersed in the dispersion so that particles adhered to the surface of the fiber. Then, the particles were dried by blowing air at room temperature to fix the particles on the surface of the fiber. The adhesion rate of the particles was 12% by mass based on the weight of the nonwoven fabric before the particles were adhered.
Next, polyethylene oxide having an average molecular weight of 60,000 and LiClO ₄ previously dried under vacuum at 80 ° C. were dissolved in an acetonitrile solvent at a molar ratio of 10: 1, and this solution was impregnated into the polymer electrolyte support and dried under reduced pressure. Acetonitrile was removed. Thereafter, the resultant was sandwiched between release films and pressed under pressure while being heated and dried at 100 ° C. to produce a polymer electrolyte having a thickness of 20 μm.
[0038]
<Measurement of ionic conductivity>
The ionic conductivity of the polymer electrolyte was measured by the AC impedance method described below. The polymer electrolyte was cut into a disk having a diameter of 10 mm, and a platinum disk having a diameter of 10 mm was applied to both surfaces thereof. A load of 9 N was applied to the platinum disk from both directions to compress the polymer electrolyte to a thickness of 20 μm, and this was used as an electrode for impedance measurement to form an ion conductivity measurement cell. The AC impedance was measured by inputting an AC of 10 mV (frequency value is 10 mHz to 1 MHz) using an impedance analyzer.
[0039]
<Short resistance measurement method>
FIG. 1 shows a schematic diagram of an apparatus used for measuring short-circuit resistance. The polymer electrolyte 1 was sandwiched from above and below by a SUS cylinder 2 having a diameter of 50 mm, and a spring 3 was used to apply a load of 14 kPa to the polymer electrolyte. The upper and lower SUS cylinders 2 are electrically insulated by a heat-resistant insulating plate 4. A voltage of 1.6 V was applied thereto, and the mixture was placed in a programmable high-temperature bath, and the temperature was raised from room temperature to 250 ° C. in 10 hours. When the temperature becomes high enough to dissolve the solid electrolyte, pressure is applied between the positive electrode and the negative electrode, and the polymer electrolyte flows to short-circuit both electrodes. Whether or not a short circuit occurred was determined by the resistance measuring device 5, and the short-circuit resistance was evaluated at the temperature at which the short circuit occurred.
[0040]
<Tensile strength measurement method>
The tensile strength of the polymer electrolyte was measured using an autograph AGS-5kND manufactured by Shimadzu Corporation. First, the polymer electrolyte was cut into 40 × 125 mm, and was pulled at a speed of 80 mm / min, with the interval between the pulling chucks being 65 mm. The strength at the time when the sample was broken was defined as the tensile strength.
[0041]
The ionic conductivity, short-circuit resistance and tensile strength are summarized in Table 1 below.
[0042]
(Example 2)
A polymer electrolyte was prepared in the same manner as in Example 1 except that the silica particles were changed to aluminum oxide (average primary particle size: about 20 nm), and the characteristics were measured. The adhesion rate of the particles was 10% by mass. The measurement results are shown in Table 1 below.
[0043]
(Example 3)
First, a powder mixed in a ratio of Li ₂ O: Al ₂ O ₃ : SiO ₂ = 25: 25: 50 (mass ratio) was melted at 1,350 ° C. for 2 hours, and this was quenched to produce a glass. This glass was ground in a mortar to obtain particles having an average particle size of about 0.1 μm. A polymer electrolyte was prepared and its characteristics were measured in the same manner as in Example 1 except that the silica particles were changed to the above-mentioned particles. The adhesion rate of the particles was 10% by mass. The measurement results are shown in Table 1 below.
[0044]
(Comparative Example 1)
In Example 1, a polymer electrolyte support was produced without attaching inorganic particles to the nonwoven fabric. Otherwise in the same manner as in Example 1, a polymer electrolyte was prepared and its characteristics were measured. The measurement results are shown in Table 1 below.
[0045]
(Comparative Example 2)
A nonwoven fabric having a basis weight of 5 g / m ² and a thickness of 20 μm was prepared by a papermaking method using alumina short fibers having an average diameter of 3 μm. The LiClO ₄ -containing solution prepared in Example 1 was applied to this nonwoven fabric, and thereafter, a polymer electrolyte was prepared in the same manner as in Example 1, and the characteristics were evaluated. The measurement results are shown in Table 1 below.
[0046]
[Table 1]

[0047]
From the comparison between Examples 1 to 3 and Comparative Example 1, it can be seen that, even when the same nonwoven fabric is used, if the inorganic particles adhere to the surface, the ionic conductivity is improved and the short-circuit temperature is significantly increased. . Further, it can be seen that the tensile strength is slightly improved. In particular, Example 3 shows that the use of glass particles made of Li ₂ O—Al ₂ O ₃ —SiO ₂ greatly improves ionic conductivity.
[0048]
Further, from the comparison between Examples 1 to 3 and Comparative Example 2, it can be seen that the tensile strength of the polymer electrolyte support having no organic fiber as a constituent member is greatly reduced and is not suitable for a wound type battery.
[0049]
【The invention's effect】
As is apparent from the above description, according to the present invention, since the organic fiber coated with the inorganic material is used as the constituent member, it has flexibility and heat resistance, is easy to handle, and improves the ionic conductivity of the polymer electrolyte. It is possible to provide a polymer electrolyte support that can secure necessary strength even when the polymer electrolyte becomes fluid at a high temperature. Further, a highly safe lithium secondary battery using this polymer electrolyte can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing an apparatus used for measuring short-circuit resistance in Examples and Comparative Examples.
DESCRIPTION OF SYMBOLS 1 Polymer electrolyte 2 SUS cylinder 3 Spring 4 Heat-resistant insulating plate 5 Resistance measuring instrument

Claims (10)

A polymer electrolyte support containing organic fibers coated with an inorganic substance. The polymer electrolyte support according to claim 1, which contains inorganic fibers. The inorganic substances or inorganic fibers include lithium, sodium, magnesium, calcium, barium, boron, aluminum, silicon, phosphorus, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, and selenium. 2. An oxide, sulfide, nitride or iodide of at least one element selected from the group consisting of, yttrium, zirconium, niobium, molybdenum, silver, indium, tin, antimony and tellurium. Or the polymer electrolyte support according to 2. The polymer electrolyte support according to any one of claims 1 to 3, wherein the inorganic substance or the inorganic fiber is a glass containing at least lithium, aluminum, and silicon. The polymer electrolyte support according to any one of claims 1 to 4, wherein the content of the organic fibers coated with the inorganic substance is 30% by mass or more. The total content of the organic fibers and the inorganic fibers coated with the inorganic material is 1 to 50% by mass, based on the mass of the entire polymer electrolyte including the polymer electrolyte support. Polymer electrolyte support. The polymer electrolyte support according to any one of claims 1 to 6, wherein the adhesion rate of the inorganic substance is 1 to 50% by mass based on the mass of the organic fiber before being coated with the inorganic substance. The polymer electrolyte support according to any one of claims 1 to 7, wherein the inorganic substance is in the form of particles. The polymer electrolyte support according to claim 8, wherein the inorganic material has an average particle size of 1 to 200 nm. A lithium secondary battery using the polymer electrolyte support according to claim 1.

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