阅读说明：本技术 全固体电池 (All-solid-state battery ) 是由 藤井信三 后藤裕二 小林正一 藤泽友弘 河野羊一郎 中西正典 山本智妃吕 加藤彰彦 于 2019-01-30 设计创作，主要内容包括：一种全固体电池1a,其具备电极体10,所述电极体通过在上下方向上依次层叠含有正极活性物质和固体电解质的正极层2、由固体电解质构成的电解质层4、以及含有负极活性物质和固体电解质的负极层3而形成,其中,正极活性物质是以化学式Li<Sub>2</Sub>Fe<Sub>(1-x)</Sub>M<Sub>x</Sub>P<Sub>(2-y)</Sub>A<Sub>y</Sub>O<Sub>7</Sub>表示的化合物,作为化学式中的M,至少含有Ti、V、Cr、Ni、Co中的任一种金属,并且作为A,至少含有B、C、Al、Si、Ga、Ge中的任一种元素,化学式中的x为0.8＜x≤1,化学式中的y为0≤y≤0.07,负极活性物质是以化学式TiO<Sub>2</Sub>表示的锐钛矿型氧化钛。(An all-solid-state battery 1a is provided with an electrode body 10 which is provided with a plurality of electrode bodiesFormed by stacking in order in the vertical direction a positive electrode layer 2 containing a positive electrode active material represented by the chemical formula Li and a solid electrolyte, an electrolyte layer 4 composed of a solid electrolyte, and a negative electrode layer 3 containing a negative electrode active material represented by the chemical formula Li and a solid electrolyte 2 Fe (1‑x) M x P (2‑y) A y O 7 The compound represented by the formula (I) contains at least one metal selected from Ti, V, Cr, Ni and Co as M, and contains at least one element selected from B, C, Al, Si, Ga and Ge as A, wherein x is 0.8< x <1, y is 0 < y < 0.07, and the negative electrode active material is TiO 2 Anatase titanium oxide is shown.)

1. An all-solid battery comprising an electrode body formed by stacking a positive electrode layer containing a positive electrode active material and a solid electrolyte, an electrolyte layer composed of the solid electrolyte, and a negative electrode layer containing a negative electrode active material and the solid electrolyte in this order in the vertical direction,

the positive electrode active material is represented by the chemical formula Li₂Fe_(1-x)M_xP_(2-y)A_yO₇The compound of (a) is represented by,

wherein M in the chemical formula contains at least one metal selected from Ti, V, Cr, Ni and Co, and A contains at least one element selected from B, C, Al, Si, Ga and Ge,

x in the chemical formula is more than 0.8 and less than or equal to 1,

y in the chemical formula is more than or equal to 0 and less than or equal to 0.07,

the negative active material is TiO in chemical formula₂Anatase titanium oxide is shown.

2. The all-solid battery according to claim 1, wherein the positive electrode active material contains at least one metal of Ni or Co as the M in the chemical formula.

3. The all-solid battery according to claim 1, wherein the positive electrode active material contains at least one element of Al or Si as a in the chemical formula.

4. The all-solid battery according to claim 1, wherein the positive electrode active material is represented by the formula Li₂Fe_(1-x)Co_yP₂O₇The compound of (a) is represented by,

x in the formula is 0.8< x <1,

the second Li contained in the chemical formula of the positive electrode active material contributes to the redox reaction, and has an energy density of greater than 791 mWh/g.

5. The all-solid battery according to claim 1, wherein the positive electrode active material is Li₂CoP₂O₇。

6. The all-solid battery according to claim 1, wherein the solid electrolyte is represented by the general formula Li_1.5Al_0.5Ge_1.5(PO₄)₃The compound shown in the specification.

7. The all-solid battery according to claim 1, wherein one of the front and rear directions is a direction orthogonal to the vertical direction, a positive electrode terminal is formed on one of front and rear end faces of a battery main body made of a rectangular parallelepiped sintered body, and a negative electrode terminal is formed on the other of the front and rear end faces,

the battery body is formed by embedding one or more unit cells in a solid electrolyte,

the unit cell is formed by laminating a positive electrode collector and a negative electrode collector on one of the upper and lower sides and the other of the upper and lower sides of the electrode body,

the preset positive electrode current collector is connected to the positive electrode terminal, and the preset negative electrode current collector is connected to the negative electrode terminal.

Technical Field

The present invention relates to an all-solid battery.

Background

Lithium secondary batteries are known as various secondary batteries because of their high energy density. However, in the widely used lithium secondary battery, a combustible organic electrolytic solution is used as an electrolyte. Therefore, in the lithium secondary battery, safety measures against liquid leakage, short circuit, overcharge, and the like are more strictly required than in other batteries. Therefore, in recent years, active research and development have been conducted on all-solid-state batteries using an oxide-based or sulfide-based solid electrolyte as an electrolyte. The solid electrolyte is mainly composed of an ion conductor capable of conducting ions in a solid state, and various problems caused by a flammable organic electrolyte solution, such as those of conventional lithium secondary batteries, do not occur in principle. A general all-solid battery has a structure in which a current collector is formed on an integrated sintered body (hereinafter, also referred to as a laminated electrode body) formed by sandwiching a layered solid electrolyte (electrolyte layer) between a layered positive electrode (positive electrode layer) and a layered negative electrode (negative electrode layer).

The laminated electrode body can be produced, for example, by a known green sheet (green sheet) method. One example of a manufacturing method for manufacturing a laminated electrode body using a green sheet method is shown below: first, a slurry-like positive electrode layer material containing a positive electrode active material and a solid electrolyte, a slurry-like negative electrode layer material containing a negative electrode active material and a solid electrolyte, and a slurry-like electrolyte layer material containing a solid electrolyte are formed into sheet-like green sheets, and a laminate obtained by sandwiching the green sheet made of the positive electrode layer material (hereinafter, also referred to as a positive electrode sheet) and the green sheet made of the negative electrode layer material (hereinafter, also referred to as a negative electrode sheet) between the green sheets made of the electrolyte layer material (hereinafter, also referred to as an electrolyte sheet) is pressed and the pressed laminate is calcined. This completes the laminated electrode body as a sintered body. A basic method for manufacturing an all-solid battery is described in, for example, patent document 1 below. Patent document 2 below describes a chip-type all-solid-state battery manufactured by a doctor blade (doctor blade) method.

As the electrode active material, a material used in a conventional lithium secondary battery can be used. Further, since all-solid-state batteries do not use a flammable electrolyte solution, electrode active materials that can obtain a higher potential difference and a higher energy density are also under study. For example, patent document 3 describes a chemical formula Li with extremely high energy density by simulation based on first principle calculation₂Fe_(1-x)M_xP₂O₇The positive electrode active material shown. Patent document 4 also describes that the energy density is extremely high and Li is represented by the chemical formula₂MP_(2-x)A_xO₇The positive electrode active material for a lithium secondary battery is described.

As the solid electrolyte, there can be used a solid electrolyte represented by the general formula Li_aX_bY_cP_dO_eA NASICON type oxide-based solid electrolyte is shown. As the NASICON-type oxide-based solid electrolyte, Li described in non-patent document 1 below is used_1.5Al_0.5Ge_1.5(PO₄)₃(hereinafter, also referred to as "LAGP") is widely known. In addition, non-patent document 2 below describes an outline of an all-solid battery.

Disclosure of Invention

Problems to be solved by the invention

In order to improve the characteristics of an all-solid battery, it is important to increase the potential difference between the positive electrode and the negative electrode. That is, it is necessary to appropriately select electrode active materials for the positive electrode and the negative electrode. In this regard, the positive electrode active material is preferably at a high potential (vs Li/Li) with respect to the potential of metallic lithium⁺) The negative electrode active material is preferably low in potential. However, on the other hand, in view of safety and the like, it is also necessary to select a more stable oneAn electrode active material.

The positive electrode active materials described in patent documents 3 and 4 may be represented by the chemical formula Li₂Fe_(1-x)M_xP_(2-y)A_yO₇And (4) showing. The positive electrode active material represented by the chemical formula can be expected to have a multi-electron reaction and a high energy density by simulation using the first principle calculation. However, in order to obtain a practical positive electrode active material, it is necessary to appropriately select the value of x or y in the chemical formula, and the metal corresponding to M or the element corresponding to a. In addition, since the all-solid-state battery cannot be established only with a positive electrode, it is also necessary to appropriately select a negative electrode active material suitable for the positive electrode active material.

Accordingly, an object of the present invention is to provide an all-solid battery using Li₂Fe_(1-x)M_xP_(2-y)A_yO₇The compound represented has a high energy density as a positive electrode active material.

Means for solving the problem

In order to achieve the above object, one aspect of the present invention provides an all-solid battery including an electrode body formed by stacking a positive electrode layer containing a positive electrode active material and a solid electrolyte, an electrolyte layer composed of the solid electrolyte, and a negative electrode layer containing a negative electrode active material and the solid electrolyte in this order in a vertical direction,

wherein the positive electrode active material is represented by the chemical formula Li₂Fe_(1-x)M_xP_(2-y)A_yO₇The compound of (a) is represented by,

wherein M in the chemical formula contains at least one metal selected from Ti, V, Cr, Ni and Co, and A contains at least one element selected from B, C, Al, Si, Ga and Ge,

x in the chemical formula is more than 0.8 and less than or equal to 1,

y in the chemical formula is more than or equal to 0 and less than or equal to 0.07,

the negative active material is TiO in chemical formula₂To representAnatase type titanium oxide.

The positive electrode active material may be an all-solid battery including at least one metal of Ni or Co as the M in the chemical formula. Further, the all-solid battery may contain at least one element of Al or Si as a in the chemical formula.

Preferably, the positive electrode active material is an all-solid battery having a chemical formula of Li₂Fe_(1-x)Co_yP₂O₇The compound of (a) is represented by,

x in the formula is 0.8< x <1,

the second Li contained in the chemical formula of the positive electrode active material contributes to the redox reaction, and the energy density is greater than 791 mWh/g. Also preferably, the positive electrode active material is Li₂CoP₂O₇The all-solid-state battery of (1). And, more preferably, the solid electrolyte is represented by the general formula Li_1.5Al_0.5Ge_1.5(PO₄)₃The compound shown in the specification.

Further, a positive electrode terminal is formed on one end face of the battery body composed of a rectangular parallelepiped sintered body on the front and rear sides, and a negative electrode terminal is formed on the other end face on the front and rear sides, with one of the two ends being orthogonal to the vertical direction as the front and rear direction,

the battery body is formed by embedding one or more unit cells in a solid electrolyte,

the unit cell is formed by laminating a positive electrode collector and a negative electrode collector on one of the upper and lower sides and the other of the upper and lower sides of the electrode body,

a predetermined positive electrode current collector is connected to the positive electrode terminal, and a predetermined negative electrode current collector is connected to the negative electrode terminal,

An all-solid battery is also within the scope of the present invention.

Effects of the invention

According to the present invention, there is provided an all-solid battery using Li₂Fe_(1-x)M_xP_(2-y)A_yO₇Of the representationThe compound serves as a positive electrode active material and thus has a high energy density.

Drawings

Fig. 1 is a schematic diagram of an all-solid battery according to an embodiment of the present invention.

Fig. 2 is a schematic view of the steps of manufacturing a LAGP glass used in manufacturing the all-solid battery of the above embodiment.

Fig. 3 is a schematic diagram of the manufacturing steps of the all-solid battery of the above embodiment.

Fig. 4 is a schematic view of the charge-discharge characteristics of the all-solid battery of the above example.

Fig. 5A is a schematic view of the charge-discharge characteristics of the all-solid battery of the above example.

Fig. 5B is a schematic diagram of the charge-discharge characteristics of the all-solid battery of the above embodiment.

Fig. 6A is a schematic view of an all-solid battery according to another embodiment of the present invention.

Fig. 6B is a schematic diagram of an all-solid battery according to another embodiment of the present invention.

Fig. 7 is a schematic view of the steps of manufacturing the all-solid-state battery according to the other embodiment described above.

Fig. 8 is a schematic view of a modification of the all-solid battery according to the other embodiment.

Fig. 9 is a schematic view of a modification of the all-solid battery according to the other embodiment.

Detailed Description

[ Cross-reference to related applications ]

The present application claims priority from japanese patent application laid-open No. 2018-027714 filed on 20/2/2018 and japanese patent application laid-open No. 2018-201183 filed on 25/10/2018, and the contents thereof are cited.

The process of the invention is intended to be carried out

Patent documents 3 and 4 disclose positive electrode active materials for lithium secondary batteries that operate by a multiple electron reaction based on simulations calculated using a first principle. The positive electrode active materials described in patent documents 3 and 4 are represented by the chemical formula Li₂Fe_(1-x)M_xP_(2-y)A_yO₇In addition to the above, a compound in which M in the chemical formula is at least one metal selected from the group consisting of Ti, V, Cr, Ni and Co, and A in the chemical formula is any one element selected from the group consisting of B, C, Al, Si, Ga and Ge, can be defined. Patent documents 3 and 4 describe Li in which M is Co, x is 1, and y is 0₂CoP₂O₇. Patent document 3 describes that the value of y in the chemical formula is preferably 0 based on the above simulation<y is less than or equal to 0.07. Therefore, the positive electrode active material including both the positive electrode active materials described in patent documents 3 and 4 is represented by the chemical formula Li₂Fe_(1-x)M_xP_(2-y)A_yO₇Wherein M is at least one metal selected from the group consisting of Ti, V, Cr, Ni and Co, A is any one element selected from the group consisting of B, C, Al, Si, Ga and Ge, and 0<x is less than or equal to 1, and y is less than or equal to 0 and less than or equal to 0.07. The positive electrode active material is expected to have a high potential (vs Li/Li) against the potential of metallic lithium by a multi-electron reaction through simulation⁺). The all-solid-state battery according to the example of the present invention uses the compound as a positive electrode active material (hereinafter, may be referred to as a positive electrode active material of the example).

However, as described above, the all-solid-state battery cannot be established only with the positive electrode. Therefore, the present inventors have made extensive studies on the negative electrode of the all-solid-state battery using the positive electrode active material of the above-described example. As a result, the positive electrode active material of the above example was used, and TiO of the chemical formula was used₂The anatase-type titanium oxide shown can be used as a negative electrode active material to obtain an all-solid-state battery having a high energy density. The present invention has been completed through such a process.

Example, a method of manufacturing a semiconductor device, and a semiconductor device

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings used in the following description, the same or similar portions may be denoted by the same reference numerals and overlapping description may be omitted. Some of the figures omit unnecessary labels in the description.

Fig. 1 is a schematic diagram of the structure of an all-solid battery 1a of the embodiment of the invention. Fig. 1 is a longitudinal sectional view of an all-solid-state battery 1a taken along a plane including layers (2 to 4) in a laminated electrode assembly 10 in the laminating direction. When the stacking direction is set to the vertical direction and the positive electrode layer 2 is stacked above the electrolyte layer 4, the stacked electrode assembly 10 of the all-solid battery 1a has a structure in which: the positive electrode layer 2, the electrolyte layer 4, and the negative electrode layer 3 are stacked in this order from the top to the bottom, and the positive electrode current collector 5 and the negative electrode current collector 6 each made of a metal foil are formed on the top surface of the positive electrode layer 2 and the bottom surface of the negative electrode layer 3, respectively.

The all-solid-state battery 1a according to the embodiment of the present invention contains the positive electrode active material according to the above-described embodiment in the positive electrode layer, and contains anatase-type titanium oxide (hereinafter referred to as TiO) in the negative electrode layer₂) The negative electrode active material is formed. And, LAGP is used as a solid electrolyte. In order to evaluate the characteristics of the all-solid-state batteries 1a of the examples, LiCoPO was used as the positive electrode active material and the negative electrode active material of the various all-solid-state batteries using the positive electrode active material and the negative electrode active material of the examples having different components₄The negative electrode active material is TiO₂The all-solid-state battery of (1) was produced as a sample, and the charge capacity and discharge capacity of each sample were measured.

The manufacturing steps of the sample are as follows

In the all-solid battery 1a of the embodiment, the positive electrode active material and the negative electrode active material can be produced by, for example, a solid-phase method. The solid electrolyte can be produced by a solid phase method or a glass melting method. In addition, as the negative electrode active material, a material provided as a product may be used. The all-solid battery 1a of the example can be produced, for example, by a green sheet method. The steps for producing the lag, the positive electrode active material, and the all-solid battery will be described below.

< LAGP production step >