TW202005160A

TW202005160A - Secondary cell and method for manufacturing secondary cell

Info

Publication number: TW202005160A
Application number: TW108117941A
Authority: TW
Inventors: 工藤拓夫; 齋藤友和
Original assignee: 日商日本麥克隆尼股份有限公司
Priority date: 2018-05-28
Filing date: 2019-05-24
Publication date: 2020-01-16
Also published as: TWI698041B; WO2019230216A1; JP2019207907A

Abstract

Provided is a technology for improving the performance of a secondary battery. A secondary battery according to the present disclosure is provided with: a base material (11); an n-type oxide semiconductor layer (13) formed on the base material (11) and formed from titanium dioxide; a charging layer (14) formed on the n-type oxide semiconductor layer (13) and including an n-type oxide semiconductor material and an insulation material; a p-type oxide semiconductor layer (16) formed on the charging layer (14); and a second electrode (17) formed on the p-type oxide semiconductor layer (16). The n-type oxide semiconductor layer (13) includes titanium dioxide having an anatase structure and titanium dioxide having a rutile structure.

Description

Secondary battery and method for manufacturing secondary battery

[0001] 本發明係關於一種用以提高二次電池之性能之技術。[0001] The present invention relates to a technique for improving the performance of a secondary battery.

[0002] 專利文獻1中係揭示有一種氧化物半導體二次電池，前述氧化物半導體二次電池具備第一電極、n型氧化物半導體層、充電層、p型氧化物半導體層以及第二電極。n型氧化物半導體層包含銳鈦礦(anatase)結構的二氧化鈦。 [先前技術文獻] [專利文獻] [0003] 專利文獻1：日本特開2017-50341號公報。[0002] Patent Document 1 discloses an oxide semiconductor secondary battery that includes a first electrode, an n-type oxide semiconductor layer, a charging layer, a p-type oxide semiconductor layer, and a second electrode. The n-type oxide semiconductor layer contains anatase (structured titanium dioxide). [Prior Technical Literature] [Patent Literature] [0003] Patent Document 1: Japanese Patent Application Publication No. 2017-50341.

(發明所欲解決之課題) [0004] 在此種二次電池中，有提升性能的期望。 [0005] 本發明係有鑑於上述課題而開發完成，目的在於提供一種用以提高二次電池之性能之技術。 (用以解決課題之手段) [0006] 本實施形態之一態樣的二次電池係具備：第一電極； n型氧化物半導體層，係由形成在前述第一電極上的二氧化鈦所構成；充電層，係形成於前述n型氧化物半導體層上，且包含n型氧化物半導體材料以及絕緣材料；p型氧化物半導體層，係形成於前述充電層上；以及第二電極，係形成於前述p型氧化物半導體層上；前述n型氧化物半導體層係含有銳鈦礦結構的二氧化鈦以及金紅石(rutile)結構的二氧化鈦。 [0007] 在上述二次電池中，較佳為：在藉由對前述n型氧化物半導體層進行低掠角X射線繞射(grazing incident x-ray diffraction；簡稱GIXD)法的X射線繞射測量所得的X射線繞射圖案中，至少存在銳鈦礦(101)面的繞射強度的峰值(peak)以及金紅石(110)面的繞射強度的峰值。 [0008] 在上述二次電池中，前述第一電極亦可藉由金屬片(metal sheet)所形成；前述二氧化鈦亦可為藉由濺鍍而直接成膜於前述金屬片上的濺鍍膜。 [0009] 本實施形態的二次電池的製造方法係具備：在第一電極上形成n型氧化物半導體層的步驟；在前述n型氧化物半導體層上形成含有n型氧化物半導體材料以及絕緣材料的充電層的步驟；在前述充電層上形成p型氧化物半導體層的步驟；以及在前述p型氧化物半導體層上形成第二電極的步驟；前述n型氧化物半導體層係含有銳鈦礦結構的二氧化鈦以及金紅石結構的二氧化鈦。 [0010] 在上述二次電池的製造方法中，較佳為：前述二氧化鈦係由已使用氧氣以及氬氣的濺鍍法而成膜，前述氧氣的流量係大於前述氬氣的流量。 [0011] 在上述二次電池的製造方法中，亦可在藉由對前述n型氧化物半導體層進行低掠角X射線繞射法的X射線繞射測量所得的X射線繞射圖案中，至少存在銳鈦礦(101)面的繞射強度的峰值以及金紅石(110)面的繞射強度的峰值。 (發明功效) [0012] 依據本發明，可以提供一種用以提高二次電池之性能之技術。(Problems to be solved by the invention) [0004] In such secondary batteries, there is a desire to improve performance. [0005] The present invention was developed in view of the above-mentioned problems, and aims to provide a technique for improving the performance of a secondary battery. (Means to solve the problem) [0006] A secondary battery according to one aspect of this embodiment includes: a first electrode; an n-type oxide semiconductor layer formed of titanium dioxide formed on the first electrode; a charging layer formed on the n-type oxide On the semiconductor layer, and includes an n-type oxide semiconductor material and an insulating material; a p-type oxide semiconductor layer is formed on the charging layer; and a second electrode is formed on the p-type oxide semiconductor layer; the n The type oxide semiconductor layer contains anatase-structured titanium dioxide and rutile-structured titanium dioxide. [0007] In the above secondary battery, it is preferably obtained by X-ray diffraction measurement by a low-grazing incident x-ray diffraction (GIXD) method for the n-type oxide semiconductor layer In the X-ray diffraction pattern, at least the peak of the diffraction intensity of the anatase (101) plane and the peak of the diffraction intensity of the rutile (110) plane exist. [0008] In the above secondary battery, the first electrode may be formed by a metal sheet; the titanium dioxide may also be a sputtering film directly formed on the metal sheet by sputtering. [0009] The method for manufacturing a secondary battery of this embodiment includes the steps of forming an n-type oxide semiconductor layer on the first electrode; forming a charge containing an n-type oxide semiconductor material and an insulating material on the n-type oxide semiconductor layer A step of forming a layer; a step of forming a p-type oxide semiconductor layer on the charging layer; and a step of forming a second electrode on the p-type oxide semiconductor layer; the n-type oxide semiconductor layer contains an anatase structure Titanium dioxide and rutile titanium dioxide. [0010] In the above secondary battery manufacturing method, preferably, the titanium dioxide-based film is formed by a sputtering method using oxygen and argon, and the flow rate of the oxygen is greater than the flow rate of the argon. [0011] In the above-mentioned method for manufacturing a secondary battery, there may be at least a sharp X-ray diffraction pattern obtained by X-ray diffraction measurement by the low-sweep angle X-ray diffraction method of the n-type oxide semiconductor layer. The peak of the diffraction intensity of the titanium (101) plane and the peak of the diffraction intensity of the rutile (110) plane. (Effect of invention) [0012] According to the present invention, a technique for improving the performance of a secondary battery can be provided.

[0014] 以下，參照圖式說明本發明的實施形態之一例。以下的說明係顯示本發明之較佳的實施形態，而本發明的技術範圍並非被限定於以下的實施形態。 [0015] [二次電池之積層構造] 以下，使用圖1對本實施形態之二次電池之基本構成加以說明。圖1為表示二次電池之基本積層構造的剖面圖。再者，為了明確說明，於以下之圖中適當顯示出XYZ三維正交座標系統。Z方向成為片狀的二次電池(以下也簡稱為片狀電池)之厚度方向(積層方向)，XY平面成為與片狀電池平行之平面。另外，於XY平面中，片狀電池為矩形狀，X方向及Y方向成為與片狀電池之端邊平行之方向。 [0016] 於圖1中，二次電池10具有於基材11上依序積層有n型氧化物半導體層13、充電層14、p型氧化物半導體層16及第二電極17而成之積層體20。 [0017] 基材11係由金屬等導電性物質所形成，作為第一電極發揮功能。本實施形態中，基材11成為負極。作為基材11，例如可使用不鏽鋼(Stainless steel；SUS)片材或鋁片材等金屬片。在此使用導電性的SUS片材作為基材11。 [0018] 亦可準備由絕緣材料所構成之基材11，並於基材11上形成第一電極。於在基材11上形成第一電極之情形時，可使用鉻(Cr)或鈦(Ti)等金屬材料作為第一電極之材料。亦可使用含有鋁(Al)、銀(Ag)等之合金膜作為第一電極之材料。於將第一電極形成於基材11上之情形時，可藉由與後述第二電極17同樣的方法來形成。 [0019] 作為第一電極之形成方法，可列舉濺鍍、離子鍍(ion plating)、電子束蒸鍍、真空蒸鍍、化學蒸鍍等氣相成膜法。另外，金屬電極可藉由電解鍍覆法、非電解鍍覆法等而形成。作為用於鍍覆之金屬，通常可使用銅、銅合金、鎳、鋁、銀、金、鋅或錫等。 [0020] 於基材11上形成有n型氧化物半導體層13。n型氧化物半導體層13係包含n型氧化物半導體材料而構成。作為n型氧化物半導體層13，例如可使用二氧化鈦(TiO₂ )等。例如，n型氧化物半導體層13可藉由濺鍍等而於基材11上成膜。 [0021] 於n型氧化物半導體層13上形成有充電層14。充電層14係包含絕緣材料。作為絕緣材料，可使用矽酮樹脂。例如，作為絕緣材料，較佳為使用矽氧化物等具有矽氧烷鍵(siloxane bond)之主骨架的矽化合物(矽酮)。因此，充電層14包含作為絕緣材料的氧化矽(SiOx)。 [0022] 另外，充電層14除了絕緣材料外還包含n型氧化物半導體材料。亦即，充電層14係由將絕緣材料與n型氧化物半導體材料混合而成之混合物所形成。例如，可使用微粒子之n型氧化物半導體作為n型氧化物半導體材料。n型氧化物半導體係藉由紫外線照射而成為具備充電功能之層。 [0023] 例如，能將充電層14的n型氧化物半導體材料設為二氧化鈦。充電層14係藉由氧化矽與二氧化鈦而形成。除此以外，作為充電層14可使用之n型氧化物半導體材料，較佳為氧化錫(SnO₂ )、氧化鋅(ZnO)或氧化鎂(MgO)。亦可使用組合二氧化鈦、氧化錫、氧化鋅及氧化鎂中之兩種、三種或全部而成之材料。 [0024] 充電層14所包含之n型氧化物半導體材料與n型氧化物半導體層13所包含之n型氧化物半導體材料既可相同也可不同。例如，於n型氧化物半導體層13所包含之n型氧化物半導體材料為氧化鈦之情形時，充電層14之n型氧化物半導體材料既可為氧化鈦也可為氧化鈦以外之n型氧化物半導體材料。 [0025] 例如，充電層14係將n型氧化物半導體材料設為二氧化鈦，藉由氧化矽與二氧化鈦而形成。除此以外，作為充電層14中可使用之n型氧化物半導體材料，較佳為氧化錫(SnO₂ )或氧化鋅(ZnO)。亦可使用組合二氧化鈦、氧化錫及氧化鋅中之兩種或全部而成之材料。 [0026] 於充電層14上形成有p型氧化物半導體層16。p型氧化物半導體層16係包含p型氧化物半導體材料而構成。作為p型氧化物半導體層16之材料，可使用氧化鎳(NiO)及銅鋁氧化物(CuAlO₂ )等。例如，p型氧化物半導體層16成為厚度400nm之氧化鎳膜。p型氧化物半導體層16係藉由蒸鍍或濺鍍等成膜方法而於充電層14上成膜。 [0027] 第二電極17只要藉由導電膜而形成即可。另外，作為第二電極17之材料，可使用鉻(Cr)或銅(Cu)等金屬材料。作為其他金屬材料，有包含鋁(Al)之銀(Ag)合金等。作為前述第二電極17之形成方法，可列舉濺鍍、離子鍍、電子束蒸鍍、真空蒸鍍、化學蒸鍍等氣相成膜法。另外，金屬電極可藉由電解鍍覆法、非電解鍍覆法等而形成。作為用於鍍覆之金屬，通常可使用銅、銅合金、鎳、鋁、銀、金、鋅或錫等。例如，第二電極17成為厚度300nm之Al膜。 [0028] 上述說明中，雖設為於充電層14下配置有n型氧化物半導體層13並於充電層14上配置有p型氧化物半導體層16之構成，但n型氧化物半導體層13與p型氧化物半導體層16亦可成為相反之配置。亦即，亦可為於充電層14上配置有n型氧化物半導體層13並於充電層14下配置有p型氧化物半導體層16之構成。於該情形時，基材11成為正極，第二電極17成為負極。亦即，只要為充電層14由n型氧化物半導體層13與p型氧化物半導體層16所夾持之構成，則於充電層14上配置n型氧化物半導體層13或配置p型氧化物半導體層16皆可。換言之，二次電池10只要為將第一電極(基材11)、第一氧化物半導體層(n型氧化物半導體層13或p型氧化物半導體層16)、充電層14、第二氧化物半導體層(p型氧化物半導體層16或n型氧化物半導體層13)、第二電極17依序積層之構成即可。 [0029] 進一步地，二次電池10亦可為含有第一電極(基材11)、第一氧化物半導體層(n型氧化物半導體層13或p型氧化物半導體層16)、充電層14、第二氧化物半導體層(p型氧化物半導體層16或n型氧化物半導體層13)、第二電極17以外之層的構成。 [0030] 圖1所示之積層體20中，亦可省略一部分層或亦可追加其他層。例如亦可在充電層14與p型氧化物半導體層16之間追加鋁化合物的層。例如鋁化合物較佳為包含Al₂ O₃ (氧化鋁)、AlN(氮化鋁)、AlON(氧氮化鋁)、Al(OH)₃ (氫氧化鋁)以及SiAlON(矽氧氮化鋁)之中的至少一個。再者，亦可在p型氧化物半導體層16與充電層14之間追加包含氫氧化鎳的層。 [0031] [二氧化鈦膜的結晶結構] 接下來詳細說明n型氧化物半導體層13的較佳的結晶結構。在本實施形態中，作為與充電層14相接的n型氧化物半導體層13的材料係使用具有銳鈦礦型的結晶結構以及金紅石型的結晶結構雙方的雙相性的二氧化鈦。銳鈦礦型的二氧化鈦係具有正方晶的結晶結構，且當加熱至900℃以上時就會轉移成金紅石型(正方晶)。藉由將n型氧化物半導體層13形成作為混合有銳鈦礦型以及金紅石型之混晶結構的二氧化鈦，就可以獲得優異的電池特性。 [0032] 例如可藉由濺鍍成膜來形成銳鈦礦型以及金紅石型之混晶結構的二氧化鈦膜。例如能藉由將鈦(Ti)設為靶的反應性濺鍍來形成二氧化鈦膜。濺鍍成膜能使用氧氣(O₂ 氣體)以及氬氣(Ar氣體)。 [0033] 濺鍍成膜時，使O₂ 氣體的流量大於Ar氣體的流量。亦即，使O₂ 氣體與Ar氣體間的氣體比(O₂ /Ar)為1以上。藉由此方式能形成銳鈦礦型以及金紅石型之混晶結構的二氧化鈦膜。如此，n型氧化物半導體層13可成為由銳鈦礦以及金紅石之混合材料所構成的二氧化鈦層。 [0034] 圖2係顯示藉由二氧化鈦的結晶結構而致使的X射線繞射圖案之差異。圖2係顯示在SUS片材上形成有二氧化鈦膜之狀態下的X射線繞射圖案(X射線繞射光譜)之資料(以下亦稱為XRD資料)的圖。 [0035] 圖2中，橫軸為繞射角度2θ(入射X射線方向與繞射X射線方向所成的角度)，縱軸為繞射強度(a.u.)。在本實施形態中，係以波長1.5418埃(angstrom)的CuKα射線的低掠角X射線繞射法進行X射線繞射測量。 [0036] 當將結晶的晶格間隔設為d、將X射線波長設為λ時，就會在滿足2dsinθ=nλ時，使峰值出現於X射線繞射圖案中(n為1以上的整數)。從而，可以根據成為峰值的2θ之值特定二氧化鈦的結晶結構。例如，在銳鈦礦(101)中峰值是在2θ=25.3(110)中峰值是在2θ=27.4。進一步地，銳鈦礦(004)中峰值是在2θ=37.8(200)中峰值是在2θ=48.1(200)中峰值是在2θ=39.9。 [0037] 圖2係顯示已改變氣體流量之情形時的樣品C、樣品D的XRD資料。樣品C係以O₂ 氣體流量為80sccm以及Ar氣體流量為80sccm所成膜成的二氧化鈦膜，樣品D係以O₂ 氣體流量為25sccm以及Ar氣體流量為300sccm所成膜成的二氧化鈦膜。二氧化鈦膜的膜厚度為100nm。又，將濺鍍成膜後的二氧化鈦膜加熱至300℃以上的預定的溫度。 [0038] 使O₂ 氣體與Ar氣體間的氣體比(O₂ /Ar)為1以上，藉此能使銳鈦礦結構以及金紅石結構的雙方出現峰值。亦即，使氣體比(O₂ /Ar)為1以上，藉此能形成混合有銳鈦礦結構以及金紅石結構的雙相性的二氧化鈦膜。氣體比(O₂ /Ar=80/80)為1的樣品C中，出現有2θ=25.3的峰值與2θ=27.4的峰值這二個峰值。因此，可判別樣品C中存在有銳鈦礦結構以及金紅石結構的雙方。另一方面，氣體比(O₂ /Ar=25/300)為0.083的樣品D中，雖出現有2θ=25.3的峰值，但並未出現2θ=27.4的峰值。因此，可判別樣品D中並不存在金紅石結構而是只有銳鈦礦結構的結晶。 [0039] 圖3係顯示樣品E、樣品F的I-V特性。樣品E、樣品F係具有在各個電極間形成有二氧化鈦單膜的積層結構。亦即，樣品E、樣品F在圖1所顯示的構成中係僅由基材11(第一電極)、n型氧化物半導體層13及第二電極17所構成。樣品E為具備將雙相性的二氧化鈦膜作為n型氧化物半導體層13的樣品。樣品F為具備將只有銳鈦礦結構的二氧化鈦膜作為n型氧化物半導體層13的樣品。圖3的曲線圖係將橫軸設為第一電極與第二電極之間的電壓[V]，將縱軸設為流動於第一電極與第二電極之間的電流[A]。 [0040] 樣品E中的O₂ 氣體流量為25sccm以及Ar氣體流量為300sccm，樣品F中的O₂ 氣體流量為80sccm以及Ar氣體流量為80sccm。膜厚度為100nm。又，將濺鍍成膜後的二氧化鈦膜加熱至300℃以上的預定的溫度。 [0041] 相較於樣品F，流動於樣品E的電極間的電流變小。與使用了只有銳鈦礦結構的二氧化鈦膜的電池相比，使用了混合有銳鈦礦結構以及金紅石結構的二氧化鈦膜的電池能降低電極間的漏電流(leak current)。因此能改善自放電特性。 [0042] 圖4係顯示藉由結晶結構而致使之自放電特性之差異的曲線圖。在此準備對應各個結構的複數個電池樣品，並顯示已測量自放電特性的測量結果。 [0043] 在使用了銳鈦礦結構以及金紅石結構的混合膜的電池樣品的成膜中，O₂ 氣體流量設為80sccm，Ar氣體流量設為80sccm。在使用了銳鈦礦結構的電池樣品的成膜中，O₂ 氣體流量設為25sccm，Ar氣體流量設為300sccm。膜厚度為100nm。又，將濺鍍成膜後的二氧化鈦膜加熱至300℃以上的預定的溫度。 [0044] 圖4係以相同條件對各電池樣品充滿電之後，已放置六個小時之後的剩餘容量的曲線圖。具體而言，將充滿電的容量設為100%且將剩餘容量設為自放電剩餘率(%)進行表示。在使用了銳鈦礦結構以及金紅石結構的混合膜的電池樣品中，能使自放電剩餘率成為約在50%左右。另一方面，使用了只有銳鈦礦結構的二氧化鈦膜的電池樣品中，自放電剩餘率成為約在10%左右。如此，能藉由使用銳鈦礦結構以及金紅石結構的混合膜來降低漏電流，從而能使自放電位準下降。因此，藉由本實施形態的結構能改善自放電特性，從而能得到高性能的電池。 [0045] 再者，為了判別二氧化鈦是只有銳鈦礦結構還是混合結構，只要使用上述X射線繞射即可判別。例如是在混合結構的情形下，X射線繞射中，繞射峰值係出現在銳鈦礦(101)面(2θ=25.3)以及金紅石(110)面(2θ=27.4)的雙方。亦即，利用以二氧化鈦膜已露出表面的狀態下所測量出的XRD資料，就能判斷二氧化鈦是只有銳鈦礦結構還是混合結構。在藉由對n型氧化物半導體層13進行低掠角X射線繞射法的X射線繞射測量所得的X射線繞射圖案中，存在銳鈦礦(101)面的繞射強度的峰值以及金紅石(110)面的繞射強度的峰值。 [0046] (二次電池的製造方法) 其次，參照圖5對二次電池10的製造方法加以說明。圖5係顯示二次電池的製造方法的流程圖。又，在下述的說明中，有關二次電池10的構成係適當地參照圖1。 [0047] 首先，準備成為第一電極的基材11(S1)。基材11為上述SUS片材。當然，也可以使用SUS片材之外的導電性片材或金屬基板等作為基材11。並且，在使用絕緣性片材來作為基材的情形下，亦可在絕緣性片材上成膜有成為第一電極的電極。 [0048] 其次，在基材11上形成n型氧化物半導體層13(S2)。n型氧化物半導體層13係直接成膜於作為基材11的SUS片材上的濺鍍膜。n型氧化物半導體層13的二氧化鈦膜係以與基材11相接的方式所形成。例如，用已使用鈦(Ti)靶的濺鍍法，將厚度50nm至200nm的二氧化鈦(TiO₂ )膜形成於基材11上。 [0049] 如上所述，一邊供給氬氣與氧氣一邊實施反應性濺鍍，藉此使二氧化鈦膜作為n型氧化物半導體層13而成膜。並且，實施作為氣體比(O₂ /Ar)為1以上的反應性濺鍍。藉此能形成混合有銳鈦礦結構以及金紅石結構的二氧化鈦膜。 [0050] 其次，在n型氧化物半導體層13上形成充電層14(S3)。充電層14能使用塗布熱分解法來形成。首先，準備於氧化鈦、或氧化錫、亦或氧化鋅之前驅體與矽油之混合物中混合溶劑而成之塗布液。此處，充電層14以將作為絕緣材料的氧化矽作為n型氧化物半導體材料設為氧化鈦為例進行說明。此情形下，能使用作為氧化鈦的前驅體的脂肪酸鈦。將脂肪酸鈦與聚矽氧油與溶劑一起攪拌，從而準備塗布液。 [0051] 藉由旋轉塗布法、狹縫(slit)塗布法等將塗布液塗布於n型氧化物半導體層13上。具體而言，藉由旋轉塗布裝置以轉速500rpm至3000rpm進行塗布液的塗布。 [0052] 接著對塗布膜進行乾燥、燒成及UV(ultra violet；紫外線)照射，藉此可於n型氧化物半導體層13上形成充電層14。例如，塗布後在加熱板(hot plate)上乾燥。在加熱板上的乾燥溫度為30℃至200℃左右，乾燥時間為5分鐘至30分鐘左右。乾燥後使用燒成爐在大氣中進行燒成。燒成溫度例如為300℃至600℃左右，燒成時間為10分鐘至60分鐘左右。 [0053] 藉此，能形成由脂肪族酸鹽所分解的矽微粒子與二氧化鈦的微粒子進行混合的層。藉由低壓水銀燈對燒成後的塗布膜照射UV光。UV照射時間為10分鐘至60分鐘。 [0054] 再者，在充電層14的n型氧化物半導體材料為氧化鈦的情形下，作為前驅體之另一例，例如可使用硬脂酸鈦。氧化鈦、氧化錫、氧化鋅係由作為金屬氧化物之前驅體的脂肪族酸鹽分解而形成。關於氧化鈦、氧化錫、氧化鋅等，亦能不使用前驅體而是使用氧化物半導體的細微粒子。將氧化鈦或氧化鋅的奈米粒子與矽油混合，藉此產生混合液。進一步將溶劑混合至混合液，藉此產生塗布液。 [0055] 在充電層14上形成p型氧化物半導體層16(S4)。p型氧化物半導體層16為氧化鎳(NiO)層。藉由將鎳或氧化鎳作為靶的濺鍍法，於充電層14上形成p型氧化物半導體層16。p型氧化物半導體層16的厚度例如為100nm至400nm。另外，p型氧化物半導體層16的形成方法並不限於濺鍍法，而可以使用蒸鍍法、離子鍍法、MBE(Molecular Beam Epitaxy；分子束磊晶)法等的薄膜形成方法。再者，亦可使用印刷法或旋塗法等的塗布形成方法來形成p型氧化物半導體層16。 [0056] 在p型氧化物半導體層16上形成第二電極17(S5)。作為第二電極17之形成方法，可列舉濺鍍、離子鍍、電子束蒸鍍、真空蒸鍍、化學蒸鍍等氣相成膜法。再者，亦可使用遮罩局部地成膜第二電極17。另外，第二電極17可藉由電解鍍覆法、非電解鍍覆法等而形成。作為用於鍍覆之金屬，通常可使用銅、銅合金、鎳、鋁、銀、金、鋅或錫等。例如，第二電極17成為厚度300nm之Al膜。 [0057] 藉由上述製造方法能製造高性能的二次電池10。特別是能製造漏電流小的二次電池10。 [0058] 以上，雖然已說明本發明的實施形態之一例，但是本發明係涵蓋不損其目的以及優點的適當變化，且不受上述實施形態的限定。 [0059] 本申請案係以2018年5月28日所提出申請的日本特願2018-101328作為基礎而主張優先權，且將日本特願2018-101328揭示的全部內容編入於此。[0014] Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. The following description shows preferred embodiments of the present invention, and the technical scope of the present invention is not limited to the following embodiments. [Laminated Structure of Secondary Battery] The basic structure of the secondary battery of this embodiment will be described below using FIG. 1. FIG. 1 is a cross-sectional view showing a basic layered structure of a secondary battery. In addition, for the sake of clarity, the XYZ three-dimensional orthogonal coordinate system is appropriately displayed in the following figures. The Z direction becomes the thickness direction (stacking direction) of a sheet-shaped secondary battery (hereinafter also simply referred to as a sheet battery), and the XY plane becomes a plane parallel to the sheet battery. In addition, in the XY plane, the sheet battery has a rectangular shape, and the X direction and the Y direction become directions parallel to the edge of the sheet battery. [0016] In FIG. 1, the secondary battery 10 has a laminate in which an n-type oxide semiconductor layer 13, a charging layer 14, a p-type oxide semiconductor layer 16, and a second electrode 17 are sequentially stacked on a substrate 11体20。 20. [0017] The base material 11 is formed of a conductive material such as metal, and functions as a first electrode. In this embodiment, the base material 11 becomes a negative electrode. As the base material 11, for example, a metal sheet such as a stainless steel (SUS) sheet or an aluminum sheet can be used. Here, a conductive SUS sheet is used as the base material 11. [0018] A substrate 11 made of an insulating material may also be prepared, and a first electrode may be formed on the substrate 11. In the case of forming the first electrode on the substrate 11, a metal material such as chromium (Cr) or titanium (Ti) may be used as the material of the first electrode. As the material of the first electrode, an alloy film containing aluminum (Al), silver (Ag), or the like can also be used. When the first electrode is formed on the substrate 11, it can be formed by the same method as the second electrode 17 described later. [0019] Examples of the method for forming the first electrode include vapor deposition methods such as sputtering, ion plating, electron beam evaporation, vacuum evaporation, and chemical evaporation. In addition, the metal electrode can be formed by an electrolytic plating method, a non-electrolytic plating method, or the like. As the metal used for plating, copper, copper alloy, nickel, aluminum, silver, gold, zinc, tin, or the like can be generally used. [0020] An n-type oxide semiconductor layer 13 is formed on the substrate 11. The n-type oxide semiconductor layer 13 is composed of an n-type oxide semiconductor material. As the n-type oxide semiconductor layer 13, for example, titanium dioxide (TiO ₂ ) or the like can be used. For example, the n-type oxide semiconductor layer 13 can be formed on the substrate 11 by sputtering or the like. [0021] A charging layer 14 is formed on the n-type oxide semiconductor layer 13. The charging layer 14 contains an insulating material. As the insulating material, silicone resin can be used. For example, as the insulating material, a silicon compound (silicone) having a main skeleton of a siloxane bond such as silicon oxide is preferably used. Therefore, the charging layer 14 contains silicon oxide (SiOx) as an insulating material. [0022] In addition, the charging layer 14 includes an n-type oxide semiconductor material in addition to an insulating material. That is, the charging layer 14 is formed of a mixture of an insulating material and an n-type oxide semiconductor material. For example, an n-type oxide semiconductor of fine particles can be used as an n-type oxide semiconductor material. The n-type oxide semiconductor becomes a layer with a charging function by ultraviolet irradiation. [0023] For example, the n-type oxide semiconductor material of the charging layer 14 can be titanium dioxide. The charging layer 14 is formed by silicon oxide and titanium dioxide. In addition to this, the n-type oxide semiconductor material that can be used as the charging layer 14 is preferably tin oxide (SnO ₂ ), zinc oxide (ZnO), or magnesium oxide (MgO). It is also possible to use a combination of two, three or all of titanium dioxide, tin oxide, zinc oxide and magnesium oxide. [0024] The n-type oxide semiconductor material included in the charging layer 14 and the n-type oxide semiconductor material included in the n-type oxide semiconductor layer 13 may be the same or different. For example, when the n-type oxide semiconductor material included in the n-type oxide semiconductor layer 13 is titanium oxide, the n-type oxide semiconductor material of the charging layer 14 may be either titanium oxide or an n-type other than titanium oxide Oxide semiconductor materials. [0025] For example, the charging layer 14 is made of titanium oxide as an n-type oxide semiconductor material, and is formed of silicon oxide and titanium dioxide. In addition, as the n-type oxide semiconductor material usable in the charging layer 14, tin oxide (SnO ₂ ) or zinc oxide (ZnO) is preferable. It is also possible to use a combination of two or all of titanium dioxide, tin oxide and zinc oxide. [0026] A p-type oxide semiconductor layer 16 is formed on the charging layer 14. The p-type oxide semiconductor layer 16 is composed of a p-type oxide semiconductor material. As a material of the p-type oxide semiconductor layer 16, nickel oxide (NiO), copper aluminum oxide (CuAlO ₂ ), or the like can be used. For example, the p-type oxide semiconductor layer 16 becomes a nickel oxide film with a thickness of 400 nm. The p-type oxide semiconductor layer 16 is formed on the charging layer 14 by a film formation method such as evaporation or sputtering. [0027] The second electrode 17 may be formed by a conductive film. In addition, as the material of the second electrode 17, a metal material such as chromium (Cr) or copper (Cu) can be used. As other metal materials, there are silver (Ag) alloys including aluminum (Al) and the like. Examples of the method for forming the second electrode 17 include vapor deposition methods such as sputtering, ion plating, electron beam evaporation, vacuum evaporation, and chemical evaporation. In addition, the metal electrode can be formed by an electrolytic plating method, a non-electrolytic plating method, or the like. As the metal used for plating, copper, copper alloy, nickel, aluminum, silver, gold, zinc, tin, or the like can be generally used. For example, the second electrode 17 becomes an Al film with a thickness of 300 nm. [0028] In the above description, although the n-type oxide semiconductor layer 13 is disposed under the charging layer 14 and the p-type oxide semiconductor layer 16 is disposed on the charging layer 14, the n-type oxide semiconductor layer 13 The configuration opposite to the p-type oxide semiconductor layer 16 may be reversed. That is, the n-type oxide semiconductor layer 13 may be disposed on the charging layer 14 and the p-type oxide semiconductor layer 16 may be disposed under the charging layer 14. In this case, the base material 11 becomes a positive electrode, and the second electrode 17 becomes a negative electrode. That is, as long as the charging layer 14 is composed of the n-type oxide semiconductor layer 13 and the p-type oxide semiconductor layer 16, the n-type oxide semiconductor layer 13 or the p-type oxide is arranged on the charging layer 14 Both semiconductor layers 16 are acceptable. In other words, as long as the secondary battery 10 is composed of the first electrode (substrate 11), the first oxide semiconductor layer (n-type oxide semiconductor layer 13 or p-type oxide semiconductor layer 16), the charging layer 14, and the second oxide The semiconductor layer (p-type oxide semiconductor layer 16 or n-type oxide semiconductor layer 13) and the second electrode 17 may be stacked in this order. [0029] Further, the secondary battery 10 may include a first electrode (substrate 11), a first oxide semiconductor layer (n-type oxide semiconductor layer 13 or p-type oxide semiconductor layer 16), and a charging layer 14 2. Structure of layers other than the second oxide semiconductor layer (p-type oxide semiconductor layer 16 or n-type oxide semiconductor layer 13) and the second electrode 17. [0030] In the laminate 20 shown in FIG. 1, some layers may be omitted or other layers may be added. For example, a layer of aluminum compound may be added between the charging layer 14 and the p-type oxide semiconductor layer 16. For example, the aluminum compound preferably includes Al ₂ O ₃ (aluminum oxide), AlN (aluminum nitride), AlON (aluminum oxynitride), Al(OH) ₃ (aluminum hydroxide), and SiAlON (aluminum silicon oxynitride) At least one of them. Furthermore, a layer containing nickel hydroxide may be added between the p-type oxide semiconductor layer 16 and the charging layer 14. [Crystal Structure of Titanium Dioxide Film] Next, a preferable crystal structure of the n-type oxide semiconductor layer 13 will be described in detail. In the present embodiment, as the material of the n-type oxide semiconductor layer 13 in contact with the charging layer 14, biphasic titanium dioxide having both an anatase type crystal structure and a rutile type crystal structure is used. The anatase-type titanium dioxide has a crystal structure of tetragonal crystals, and when heated to above 900°C, it will be transformed into a rutile type (tetragonal crystal). By forming the n-type oxide semiconductor layer 13 as titanium dioxide having a mixed crystal structure mixed with anatase type and rutile type, excellent battery characteristics can be obtained. [0032] For example, a titanium dioxide film with a mixed crystal structure of anatase type and rutile type can be formed by sputtering. For example, a titanium dioxide film can be formed by reactive sputtering using titanium (Ti) as a target. For sputtering film formation, oxygen (O ₂ gas) and argon (Ar gas) can be used. [0033] When forming a film by sputtering, the flow rate of O ₂ gas is made larger than the flow rate of Ar gas. That is, the gas ratio (O ₂ /Ar) between O ₂ gas and Ar gas is 1 or more. In this way, anatase-type and rutile-type titania films can be formed. In this way, the n-type oxide semiconductor layer 13 can be a titanium dioxide layer composed of a mixed material of anatase and rutile. [0034] FIG. 2 shows the difference in X-ray diffraction patterns caused by the crystal structure of titanium dioxide. FIG. 2 is a diagram showing data of an X-ray diffraction pattern (X-ray diffraction spectrum) (hereinafter also referred to as XRD data) in a state where a titanium dioxide film is formed on a SUS sheet. [0035] In FIG. 2, the horizontal axis is the diffraction angle 2θ (the angle formed by the incident X-ray direction and the diffraction X-ray direction), and the vertical axis is the diffraction intensity (au). In the present embodiment, the X-ray diffraction measurement is performed by the low-sweep angle X-ray diffraction method of CuKα rays with a wavelength of 1.5418 angstrom. [0036] When the lattice interval of the crystal is d and the X-ray wavelength is λ, a peak appears in the X-ray diffraction pattern (n is an integer of 1 or more) when 2dsinθ=nλ is satisfied. . Therefore, the crystal structure of titanium dioxide can be specified based on the value of 2θ which becomes a peak. For example, the peak value in anatase (101) is 2θ=25.3 (110) and the peak value is 2θ=27.4. Further, the peak value in anatase (004) is 2θ=37.8 (200), the peak value is 2θ=48.1 (200), and the peak value is 2θ=39.9. [0037] FIG. 2 shows the XRD data of sample C and sample D when the gas flow rate has been changed. Sample C is a titanium dioxide film formed with an O ₂ gas flow rate of 80 sccm and Ar gas flow rate of 80 sccm. Sample D is a titanium dioxide film formed with an O ₂ gas flow rate of 25 sccm and Ar gas flow rate of 300 sccm. The film thickness of the titanium dioxide film is 100 nm. Furthermore, the titanium dioxide film after sputtering is heated to a predetermined temperature of 300° C. or higher. [0038] By setting the gas ratio between the O ₂ gas and the Ar gas (O ₂ /Ar) to 1 or more, peaks can appear in both the anatase structure and the rutile structure. That is, by setting the gas ratio (O ₂ /Ar) to 1 or more, a biphasic titanium dioxide film mixed with an anatase structure and a rutile structure can be formed. In sample C with a gas ratio (O ₂ /Ar=80/80) of 1, two peaks of 2θ=25.3 peak and 2θ=27.4 peak appeared. Therefore, it can be judged that both the anatase structure and the rutile structure exist in the sample C. On the other hand, in the sample D having a gas ratio (O ₂ /Ar=25/300) of 0.083, although a peak of 2θ=25.3 appeared, a peak of 2θ=27.4 did not appear. Therefore, it can be judged that there is no rutile structure in sample D but only crystals of anatase structure. [0039] FIG. 3 shows the IV characteristics of Sample E and Sample F. Samples E and F have a laminated structure in which a single titanium dioxide film is formed between the electrodes. That is, in the configuration shown in FIG. 1, the samples E and F are composed only of the base material 11 (first electrode), the n-type oxide semiconductor layer 13 and the second electrode 17. Sample E is a sample having a biphasic titanium dioxide film as the n-type oxide semiconductor layer 13. Sample F is a sample having a titanium dioxide film having only an anatase structure as the n-type oxide semiconductor layer 13. 3 is a graph in which the horizontal axis is the voltage [V] between the first electrode and the second electrode, and the vertical axis is the current [A] flowing between the first electrode and the second electrode. [0040] The O ₂ gas flow rate in the sample E is 25 sccm and the Ar gas flow rate is 300 sccm, and the O ₂ gas flow rate in the sample F is 80 sccm and the Ar gas flow rate is 80 sccm. The film thickness is 100 nm. Furthermore, the titanium dioxide film after sputtering is heated to a predetermined temperature of 300° C. or higher. [0041] Compared with sample F, the current flowing between the electrodes of sample E becomes smaller. Compared with a battery using a titanium dioxide film having only an anatase structure, a battery using a titanium dioxide film mixing an anatase structure and a rutile structure can reduce the leakage current between the electrodes. Therefore, self-discharge characteristics can be improved. 4 is a graph showing the difference in self-discharge characteristics caused by the crystal structure. Here, a plurality of battery samples corresponding to each structure are prepared, and the measurement results of the measured self-discharge characteristics are displayed. [0043] In the formation of a battery sample using a mixed film of anatase structure and rutile structure, the O ₂ gas flow rate was 80 sccm, and the Ar gas flow rate was 80 sccm. In the formation of a battery sample using an anatase structure, the O ₂ gas flow rate was 25 sccm, and the Ar gas flow rate was 300 sccm. The film thickness is 100 nm. Furthermore, the titanium dioxide film after sputtering is heated to a predetermined temperature of 300° C. or higher. [0044] FIG. 4 is a graph of the remaining capacity after having been left for six hours after fully charging each battery sample under the same conditions. Specifically, the fully charged capacity is represented by 100% and the remaining capacity is represented by the self-discharge remaining rate (%). In a battery sample using a mixed film of anatase structure and rutile structure, the self-discharge residual rate can be about 50%. On the other hand, in a battery sample using a titanium dioxide film having only an anatase structure, the residual rate of self-discharge becomes about 10%. In this way, the leakage current can be reduced by using a mixed film of anatase structure and rutile structure, so that the self-discharge level can be reduced. Therefore, with the structure of this embodiment, the self-discharge characteristics can be improved, and a high-performance battery can be obtained. [0045] Furthermore, in order to discriminate whether titanium dioxide has only anatase structure or mixed structure, it can be discriminated by using the above-mentioned X-ray diffraction. For example, in the case of a mixed structure, in X-ray diffraction, diffraction peaks appear on both the anatase (101) plane (2θ=25.3) and the rutile (110) plane (2θ=27.4). That is, using XRD data measured in a state where the titanium dioxide film has been exposed to the surface, it can be judged whether the titanium dioxide has only the anatase structure or the mixed structure. In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the n-type oxide semiconductor layer 13 by a low-sweep angle X-ray diffraction method, there is a peak of diffraction intensity of the anatase (101) plane and The peak value of the diffraction intensity of the rutile (110) plane. [Method of Manufacturing Secondary Battery] Next, the method of manufacturing the secondary battery 10 will be described with reference to FIG. 5. FIG. 5 is a flowchart showing a method of manufacturing a secondary battery. In the following description, the configuration of the secondary battery 10 is appropriately referred to FIG. 1. [0047] First, the base material 11 to be the first electrode is prepared (S1). The substrate 11 is the above-mentioned SUS sheet. Of course, a conductive sheet other than the SUS sheet, a metal substrate, or the like may be used as the base material 11. In addition, when an insulating sheet is used as the base material, an electrode that becomes the first electrode may be formed on the insulating sheet. [0048] Next, an n-type oxide semiconductor layer 13 is formed on the substrate 11 (S2). The n-type oxide semiconductor layer 13 is a sputtering film formed directly on the SUS sheet as the base material 11. The titanium dioxide film of the n-type oxide semiconductor layer 13 is formed so as to be in contact with the base material 11. For example, a titanium dioxide (TiO ₂ ) film with a thickness of 50 nm to 200 nm is formed on the substrate 11 by a sputtering method using a titanium (Ti) target. As described above, reactive sputtering is performed while supplying argon gas and oxygen gas, thereby forming a titanium dioxide film as the n-type oxide semiconductor layer 13. Furthermore, reactive sputtering is performed as a gas ratio (O ₂ /Ar) of 1 or more. Thereby, a titanium dioxide film mixed with anatase structure and rutile structure can be formed. [0050] Next, the charging layer 14 is formed on the n-type oxide semiconductor layer 13 (S3). The charging layer 14 can be formed using a coating thermal decomposition method. First, prepare a coating solution prepared by mixing a solvent with a mixture of titanium oxide, tin oxide, or zinc oxide precursor and silicone oil. Here, the charging layer 14 will be described by taking silicon oxide as an insulating material as an n-type oxide semiconductor material and using titanium oxide as an example. In this case, fatty acid titanium which is a precursor of titanium oxide can be used. The fatty acid titanium, silicone oil and solvent are stirred together to prepare a coating solution. [0051] The coating liquid is applied on the n-type oxide semiconductor layer 13 by a spin coating method, a slit coating method, or the like. Specifically, the coating liquid is applied by a spin coating device at a rotation speed of 500 rpm to 3000 rpm. [0052] Next, the coating film is dried, fired, and UV (ultra violet; ultraviolet) irradiation, whereby the charging layer 14 can be formed on the n-type oxide semiconductor layer 13. For example, after coating, it is dried on a hot plate. The drying temperature on the hot plate is about 30°C to 200°C, and the drying time is about 5 minutes to 30 minutes. After drying, it is fired in the atmosphere using a firing furnace. The firing temperature is, for example, about 300°C to 600°C, and the firing time is about 10 minutes to 60 minutes. [0053] With this, it is possible to form a layer in which silicon fine particles decomposed by aliphatic acid salts and fine particles of titanium dioxide are mixed. The fired coating film was irradiated with UV light by a low-pressure mercury lamp. The UV irradiation time is 10 minutes to 60 minutes. [0054] Furthermore, when the n-type oxide semiconductor material of the charging layer 14 is titanium oxide, as another example of the precursor, for example, titanium stearate can be used. Titanium oxide, tin oxide, and zinc oxide are formed by decomposition of fatty acid salts as precursors of metal oxides. For titanium oxide, tin oxide, zinc oxide, etc., fine particles of an oxide semiconductor can be used instead of a precursor. Nanoparticles of titanium oxide or zinc oxide are mixed with silicone oil, thereby generating a mixed liquid. The solvent is further mixed to the mixed liquid, thereby generating a coating liquid. [0055] A p-type oxide semiconductor layer 16 is formed on the charging layer 14 (S4). The p-type oxide semiconductor layer 16 is a nickel oxide (NiO) layer. The p-type oxide semiconductor layer 16 is formed on the charging layer 14 by sputtering using nickel or nickel oxide as a target. The thickness of the p-type oxide semiconductor layer 16 is, for example, 100 nm to 400 nm. In addition, the formation method of the p-type oxide semiconductor layer 16 is not limited to the sputtering method, and a thin film formation method such as a vapor deposition method, an ion plating method, an MBE (Molecular Beam Epitaxy) method, or the like can be used. In addition, the p-type oxide semiconductor layer 16 may be formed using a coating method such as a printing method or a spin coating method. [0056] A second electrode 17 is formed on the p-type oxide semiconductor layer 16 (S5). Examples of the method for forming the second electrode 17 include vapor deposition methods such as sputtering, ion plating, electron beam evaporation, vacuum evaporation, and chemical evaporation. Furthermore, the second electrode 17 may be formed locally using a mask. In addition, the second electrode 17 can be formed by an electrolytic plating method, a non-electrolytic plating method, or the like. As the metal used for plating, copper, copper alloy, nickel, aluminum, silver, gold, zinc, tin, or the like can be generally used. For example, the second electrode 17 becomes an Al film with a thickness of 300 nm. [0057] The high-performance secondary battery 10 can be manufactured by the above manufacturing method. In particular, the secondary battery 10 with a small leakage current can be manufactured. [0058] Although an example of the embodiment of the present invention has been described above, the present invention covers appropriate changes that do not impair its purpose and advantages, and is not limited by the above-described embodiment. [0059] This application claims priority based on Japanese Patent Application 2018-101328 filed on May 28, 2018, and incorporates all the contents disclosed in Japanese Patent Application 2018-101328.

[0060] 10‧‧‧二次電池 11‧‧‧基材 13‧‧‧n型氧化物半導體層 14‧‧‧充電層 16‧‧‧p型氧化物半導體層 17‧‧‧第二電極 20‧‧‧積層體 [0060] 10‧‧‧secondary battery 11‧‧‧ Base material 13‧‧‧n-type oxide semiconductor layer 14‧‧‧Charging layer 16‧‧‧p-type oxide semiconductor layer 17‧‧‧Second electrode 20‧‧‧Layered body

[0013] 圖1係顯示氧化物半導體二次電池10之剖面結構的示意圖。圖2係顯示二氧化鈦膜的X射線繞射圖案的示意圖。圖3係顯示藉由結晶結構而致使的I-V特性之差異的曲線圖。圖4係顯示藉由結晶結構而致使自放電特性之差異的曲線圖。圖5係顯示二次電池的製造方法的流程圖。[0013] FIG. 1 is a schematic diagram showing the cross-sectional structure of an oxide semiconductor secondary battery 10. FIG. 2 is a schematic diagram showing an X-ray diffraction pattern of a titanium dioxide film. FIG. 3 is a graph showing the difference in I-V characteristics caused by the crystal structure. FIG. 4 is a graph showing the difference in self-discharge characteristics due to the crystal structure. FIG. 5 is a flowchart showing a method of manufacturing a secondary battery.

10‧‧‧二次電池 10‧‧‧secondary battery

11‧‧‧基材 11‧‧‧ Base material

13‧‧‧n型氧化物半導體層 13‧‧‧n-type oxide semiconductor layer

14‧‧‧充電層 14‧‧‧Charging layer

16‧‧‧p型氧化物半導體層 16‧‧‧p-type oxide semiconductor layer

17‧‧‧第二電極 17‧‧‧Second electrode

20‧‧‧積層體 20‧‧‧Layered body

Claims

A secondary battery with: First electrode The n-type oxide semiconductor layer is composed of titanium dioxide formed on the first electrode; The charging layer is formed on the n-type oxide semiconductor layer and includes an n-type oxide semiconductor material and an insulating material; a p-type oxide semiconductor layer formed on the aforementioned charging layer; and The second electrode is formed on the p-type oxide semiconductor layer; The aforementioned n-type oxide semiconductor layer contains anatase-structured titanium dioxide and rutile-structured titanium dioxide.

The secondary battery as recited in claim 1, wherein at least there is a sharp edge in the X-ray diffraction pattern obtained by X-ray diffraction measurement of the low-sweep angle X-ray diffraction method on the n-type oxide semiconductor layer The peak diffraction intensity of the titanium (101) plane and the peak diffraction intensity of the rutile (110) plane.

The secondary battery according to claim 1 or 2, wherein the first electrode is formed by a metal sheet; The n-type oxide semiconductor layer is a sputtering film in which the titanium dioxide is directly formed on the metal sheet by sputtering.

A method for manufacturing a secondary battery, including: The step of forming an n-type oxide semiconductor layer on the aforementioned first electrode; A step of forming a charging layer containing an n-type oxide semiconductor material and an insulating material on the aforementioned n-type oxide semiconductor layer; The step of forming a p-type oxide semiconductor layer on the aforementioned charging layer; and The step of forming the second electrode on the aforementioned p-type oxide semiconductor layer; The aforementioned n-type oxide semiconductor layer contains anatase-structured titanium dioxide and rutile-structured titanium dioxide.

The method for manufacturing a secondary battery according to claim 4, wherein the titanium dioxide is formed by a sputtering method using oxygen and argon; The flow rate of the oxygen gas is greater than the flow rate of the argon gas.

The method for manufacturing a secondary battery according to claim 4 or 5, wherein the X-ray diffraction pattern obtained by X-ray diffraction measurement by the low-sweep angle X-ray diffraction method for the n-type oxide semiconductor layer Among them, there is at least a peak of the diffraction intensity of the anatase (101) plane and a peak of the diffraction intensity of the rutile (110) plane.