201032376 六、發明說明： 【發明所屬之技術領域】 本發明乃關於鋰離子二次電池之負電極構造及 方法。 【先前技術】 鋰離子二次電池係將由Li離子進出於負電極 φ 結晶中的原子間者，產生電性化學反應者，作爲原 於充電時，Li離子乃因正離子之故，從正電極側f 離子，移動至負電極側。另外，達成經由放電時係 時相反，從負電極側釋放Li離子，移動至正電極 而作爲可重複使用之二次電池的機能。如此，鋰電 重複利用之故，對於地球環境佳，在要求省資源化 對於可積存比較大電容量而使用之鋰離子二次電池 係非常大。 • 使用於經由將Li離子進行取放而進行充放電 子二次電池之電極材料，係稱作「鋰離子二次電池 材料」。正電極側之電極材料係一般使用鈷酸鋰等 極側之電極材料係一般，作爲電極支持材而使用銅 於其表面塗布引起起電反應之石墨等而作爲電極者 對於電解質，多採用含有LiC104，LiPF6等之Li離 機電解液。並且，電極材料係更廉價且高性能之同 易引起起火事故等之材料的要求非常高。負電極側 材料係有從至目前爲止爲一般之石墨，嘗試使用錫 其製造 材料之 理。對 畢放Li 與充電 側之時 池係可 之中， 的期待 的鋰離 用電極 。負電 或鋁， 爲多。 子的有 時，不 之電極 合金等 -5- 201032376 之新素材，進行增加每單位的電性容量，作爲可以更短時 間之重複充放電，謀求高性能且長壽命化之開發。 [專利文獻] 專利文獻1:日本特開平7-176302號公報 專利文獻2:日本特開昭63-121265號公報 [非專利文獻] 非專利文獻1 :京都大學硏究所小久見善八編著、「鋰 二次電池」、日本株式會社Ohmsh a公司、2008年3月。 【發明內容】 [發明欲解決之課題] 在前述先前技術之中，專利文獻1及專利文獻2係均 有關正電極之素材的構成。另外，非專利文獻1係有有關 負電極之記載，但作爲有關石墨負電極，或Cu6Sn5的鋰 吸著之記載。但，對於Li離子進入於負電極中之充電時 ，例如於石墨之情況，因Li離子進入於結晶中，而使石 墨的結晶構造膨脹，對於充電時，從負電極釋放Li離子 之故，如重複此有負電極變脆弱之課題。並且，此等乃決 定電池本身的壽命。 另一方面，對於在非專利文獻1所示之負電極，係揭 示有使Cu與Sn之金屬間化合物的Cu6Sn5附著於銅板之 構成。一般，作爲關於如此構成之製造方法，係作爲在以 溶劑溶解Cu6Sn5的粉末，塗布於銅板之後，進行乾燥.層 壓提昇密度之嘗試。 -6 - 201032376 但，Cu6Sii5係在186°C以下從六方晶固相變化爲斜方 晶。隨之，隨著其變化而產生體體積變化等時，對於金屬 間化合物本身產生龜裂。如此，根據龜裂的產生部位或產 生型態，係有著形狀產生粉末化而產生強度下降，以及電 阻增加而有損作爲電極之信賴性之虞。另外，在電阻增加 之狀態而流動有大的電流時，亦有成爲異常發熱或起火之 原因之虞。更且，從製造工程的面而視之情況，在以往所 知之製造方法中，必須有Cu6Sn5等之微粉末的高度處理 技術及塗布技術，亦有無法避免高成本之課題。 因此，本發明係作爲廉價，簡便且安定之負電極材料 ，採用更安定之金屬間化合物者。即，作爲與Cu6Sn5另 外之金屬間化合物，著眼於（Cu，Ni)6Sn5。並且，揭示使 Cu與Ni乃可與Sn反應之該（Cu，Ni)6Sn5金屬間化合物 成長附著之構造。 〇 [爲解決課題之手段] 具體而言，本發明者係對於Cu或將Cu作爲主要要素 之合金所成的電極而言，設置其表面層，作爲全體作爲鋰 離子二次電池之負電極。表面層之構造係（Cu，Ni)6Sn5金 屬間化合物。（Cu，Ni)6Sn5金屬間化合物係Cu6Sn5金屬 間化合物之Cu的一部分置換成Ni之構成，Cu與Ni係 有全率固溶的關係之故，對於適宜添加Ni於Sn-Cu中的 情況，係產生有（Cu，Ni)6Sn5金屬間化合物。例如，對 於於Sn-Cu-Ni合金之溶融金屬中浸漬Cu電極之情況， 201032376 作爲Cu電極之表面層，接合界面乃在堅固的狀態出現 (Cu，Ni)6Sn5金屬間化合物。嚴密地更於（Cu，Ni)6Sn5金 屬間化合物之表面，出現Sn含有量多之金屬層，但此 層係經由選擇性地除去Sn之時，在嚴密的意思上，成 爲（Cu，Ni)6Sn5金屬間化合物乃作爲表面層而出現者。 (Cu，Ni)6Sn5金屬間化合物係結晶構造乃六方晶，具有在 凝固時不會引起變化而從液體成爲固體之安定的構造。隨 之，（Cu，Ni)6Sn5金屬間化合物係不易產生斷裂等，作爲 電極表面材，安定性爲高。另外，六方晶的結晶尺寸係如 與石墨之六方晶結晶構造做比較，因原子間距離爲大之故 ，即使在混入有Li離子之情況，亦可說是使結晶構造膨 脹之虞爲少。 作爲附加的手段，發明者係作爲（Cu，Ni)6Sn5金屬間 化合物之更表面層，選擇性地使用使石墨層固定之手段。 Li離子之電性化學反應係主要期待在與（Cu，Ni)6Sn5金屬 間化合物的關係，但爲了迴避經由Li離子之進出而金屬 間化合物剝離成粉狀之情況，經由石墨層而使其固定者。 石墨係從以往廣泛地採用於鋰離子二次電池的負電極之故 ，未有對於電性特性之大的課題。另外，其本身乃電阻比 較於金屬而非常大之故，假設即使產生剝離，亦可迴避經 由在短時間之內部短路等之事故。對於石墨之固定係使用 公知之技術。 另外，取代於Ni，亦使用將Co、Fe、Μη、Zn、或Pd 作爲金屬間化合物之一組成的手段。此等金屬係對於Sn- -8- 201032376201032376 VI. Description of the Invention: [Technical Field] The present invention relates to a negative electrode structure and method for a lithium ion secondary battery. [Prior Art] A lithium ion secondary battery is one in which an ion is introduced into the anode of the negative electrode φ crystal to generate an electrical chemical reaction. As a charge, Li ions are positive ions and are positive electrodes. Side f ions, moving to the negative electrode side. Further, in the case of discharging, the Li ion is released from the negative electrode side and moved to the positive electrode to function as a reusable secondary battery. In this way, lithium batteries are reused, and they are required to be resource-efficient for the global environment. Lithium-ion secondary batteries used for accumulating relatively large capacitances are very large. • An electrode material used for charging and discharging a secondary battery by picking up and discharging Li ions is called a “lithium ion secondary battery material”. The electrode material on the positive electrode side is generally an electrode material such as a lithium cobaltate or the like. Generally, as the electrode support material, copper is used to apply a graphite which causes an electroactive reaction on the surface thereof, and the electrode is used as an electrode. For the electrolyte, LiC104 is often used. Li, LiPF6, etc. Li off the electrolyte. Further, the electrode material is more expensive and high in performance, and the material which is liable to cause a fire accident or the like is extremely demanding. The material of the negative electrode side is a graphite which has been conventionally used until now, and it is attempted to use tin as a material for its manufacture. For the Li Li and the charging side of the pool, the expected lithium ionizing electrode. Negative or aluminum, more. In the case of a new material, such as an electrode alloy, etc. -5-201032376, the electric capacity per unit is increased, and the battery can be repeatedly charged and discharged in a shorter period of time, thereby achieving high performance and long life. [Patent Document 1] Japanese Unexamined Patent Publication No. Hei No. Hei. No. Hei. No. 63-121265 (Non-Patent Document) Non-Patent Document 1: A Study by Kyoto University Research Institute Secondary battery", Ohmsha, Inc., Japan, March 2008. [Problems to be Solved by the Invention] In the above prior art, Patent Document 1 and Patent Document 2 relate to the configuration of the material of the positive electrode. Further, Non-Patent Document 1 describes a negative electrode, but it is described as a graphite negative electrode or a lithium absorbing of Cu6Sn5. However, when Li ions enter the negative electrode for charging, for example, in the case of graphite, Li ions enter the crystal to expand the crystal structure of the graphite, and when charging, the Li ions are released from the negative electrode, such as Repeat this problem that the negative electrode becomes fragile. And, these are the life of the battery itself. On the other hand, in the negative electrode shown in Non-Patent Document 1, a structure in which Cu6Sn5 of an intermetallic compound of Cu and Sn is adhered to a copper plate is disclosed. In general, as a manufacturing method of such a configuration, a powder of Cu6Sn5 dissolved in a solvent is applied to a copper plate, and then dried to increase the density. -6 - 201032376 However, the Cu6Sii5 system changes from a hexagonal solid phase to an orthorhombic crystal below 186 °C. As a result, when the volume change or the like occurs due to the change, cracks occur in the intermetallic compound itself. As described above, depending on the generation site or the production type of the crack, the shape is pulverized, the strength is lowered, and the electric resistance is increased to impair the reliability of the electrode. Further, when a large current flows in a state where the resistance is increased, there is a possibility that abnormal heat or fire is caused. Further, in view of the surface of the manufacturing process, in the conventionally known manufacturing method, it is necessary to have a high-treatment technique and a coating technique of fine powder such as Cu6Sn5, and there is a problem that high cost cannot be avoided. Therefore, the present invention is an inexpensive, simple and stable negative electrode material, and a more stable intermetallic compound is used. That is, as an additional intermetallic compound with Cu6Sn5, attention is paid to (Cu, Ni)6Sn5. Further, a structure in which Cu(Ni)6Sn5 intermetallic compound which Cu and Ni react with Sn is grown and adhered is disclosed. 〇 [Means for Solving the Problem] Specifically, the inventors of the present invention provided a surface layer of an electrode made of Cu or an alloy containing Cu as a main element, and used as a negative electrode of a lithium ion secondary battery as a whole. The structure of the surface layer is a (Cu, Ni) 6Sn5 intermetallic compound. (Cu, Ni) 6Sn5 intermetallic compound Cu6Sn5 intermetallic compound Cu is partially replaced by Ni, and Cu and Ni have a full-rate solid solution relationship. For the case where Ni is suitably added to Sn-Cu, A (Cu, Ni) 6Sn5 intermetallic compound is produced. For example, in the case where the Cu electrode is immersed in the molten metal of the Sn-Cu-Ni alloy, 201032376 is used as the surface layer of the Cu electrode, and the joint interface is in a solid state (Cu, Ni) 6Sn5 intermetallic compound. Tightly more on the surface of the (Cu, Ni)6Sn5 intermetallic compound, a metal layer having a large amount of Sn is present, but this layer is (Cu, Ni) in a strict sense by selectively removing Sn. The 6Sn5 intermetallic compound appears as a surface layer. The (Cu, Ni) 6Sn5 intermetallic compound crystal structure is hexagonal crystal, and has a structure in which it does not change during solidification and becomes stable from a liquid. Further, the (Cu, Ni) 6Sn5 intermetallic compound is less likely to be broken or the like, and the stability is high as an electrode surface material. Further, the crystal size of the hexagonal crystal is compared with the hexagonal crystal structure of graphite, and since the distance between the atoms is large, even when Li ions are mixed, it can be said that the crystal structure is swollen. As an additional means, the inventors used a more surface layer of a (Cu, Ni)6Sn5 intermetallic compound, and selectively used a means for fixing the graphite layer. The electrochemical reaction of Li ions is mainly expected to be related to the intermetallic compound of (Cu, Ni)6Sn5. However, in order to avoid the peeling of the intermetallic compound into powder by the passage of Li ions, it is fixed by the graphite layer. By. Since the graphite system has been widely used in the negative electrode of a lithium ion secondary battery, it has not been a problem for electrical characteristics. Further, since the electric resistance itself is very large compared to the metal, it is assumed that even if peeling occurs, an accident such as an internal short circuit in a short time can be avoided. A well-known technique is used for the fixing of graphite. Further, instead of Ni, a means of forming Co, Fe, Μη, Zn, or Pd as one of the intermetallic compounds is also used. These metals are for Sn--8- 201032376
Cu而言，進行與Ni同樣的動作之故，爲置換可能之金屬 〇 電極之製造方法係並不限定於如上述之浸漬者，如爲於 Cu或將Cu作爲主要要素之電極的表面，可使（Cu，Ni)6Sn5 金屬間化合物出現之方法即可，而公知的回流法等亦可適 用，亦包含以含有前述之金屬間化合物的組成之粉末，膠 帶，箔及溶射等進行塗布，黏接，壓著等，從以往所知的 φ 表面處理之手法而可廣泛使用。特別是對於使用銅箔之構 成，於銅箔電鍍由Sn-Cu-Ni組成所成之焊料，之後進行 衰減處理，形成（Cu，Ni)6Sn5金屬間化合物之方法則爲有 效。 [發明之效果] 本發明之負電極構造，係可無需將從以往所知之融熔 錫的浸漬工程做大的改變而得到。另外，電極構造之表面 φ 層係因在凝固時未引起變化之六方晶的安定之（Cu，Ni)6Sn5 金屬間化合物之故，可極力迴避在表面層之製造工程，於 內部產生斷裂者，即使在物理性側面亦可作爲信賴性高的 構造。更且，結晶構造係因較石墨之六方晶尺寸爲大之故 ，對於充電時係可儲存多的Li離子之同時，如與石墨做 比較，亦可控制經由Li離子之儲存而構造產生膨脹者， 可期待作爲長壽命之電池者。 【實施方式】 -9 - 201032376 首先，先行於本發明之表面層的（Cu，Ni)6Sn5金屬間 化合物層，於以下說明關於Sn-Cu-Ni合金之作用。 圖1乃Sn-Cu二元相圖，但Sn與Cu之金屬間化合 物的Cu6Sn5係對於銅濃度乃約39.1重量％以下之情況’ 知道將較固相線溫度爲低之1 8 6 °C作爲交界，在高溫度 側係爲六方晶之Tl-CU6Sn5，在低溫度側係爲斜方晶之 rT-CiuSns，並了解由六方晶與斜方晶弓|起固相變化者。六 方晶之結晶構造係所謂稱作封閉塡充，結晶的體積乃集中 爲最小之狀態。因此，從六方晶至斜方晶，相反地從斜方 晶至六方晶產生固相變化時，同時產生體晶變化。例如， 對於融熔之Sn-Cu合金產生凝固之情況，經由溫度下降而 析出之Cu6Sn5之金屬間化合物乃對於降溫至186°C以下之 情況，亦無法避免產生其固相變化者。如此作爲時，對於 將Sn-Cu合金作爲鋰離子二次電池之負電極表面層材而使 用之情況，係有因上述現象引起，對於凝固後之Cu6Sn5 產生破裂之可能性。另外，即使對於Cu6Sn5未產生破裂 之現象的情況，亦於此係包含有固相變化時之偏應力之故 ，將比較輕度之衝擊或溫度變化等之外部應力作爲轉機而 散發其偏應力，而有伴隨龜裂或破損之虞。 另一方面，知道對於Sn-Cu加上Ni之情況，Ni係 與金屬間化合物之Cu6Sn5的Cu進行一部分置換，形成 (Cu，Ni)6Sn5者。並且，經由實驗時，對於金屬間化合物 之（Cu，Ni)6Sn5中的Ni濃度乃約2~10at%之情況，因Cu 置換成Ni之情況引起，金屬間化合物之結晶構造乃六方 -10- 201032376 晶之狀態，即使在常溫亦可確認與在變化溫度以上之高溫 度產生之Tl-Cu6Sn5相同構造者。此係認爲經由Ni乃與 Cu6Sn5之中的Cu之一部分進行置換之時，貢獻於作爲六 方晶之結晶構造之安定化者。更且，跨過六方晶與斜方晶 之相變化溫度之186°C，在100°C〜2 10°C之溫度範圍，以 1°C/分之條件實施升降溫試驗，以示差熱分析（DSC)調查相 變化時，（Cu，Ni)6Sn5之Ni濃度乃約4at%之情況，未引 0 起相變化，也就是亦確認到在高溫相之六方晶產生安定化 者。另一方面，在以相同的條件未添加Ni之Cu6Sn5之 DSC測定中，亦確認到明顯音像變化引起之變化乃在 186°C附近產生者。 圖3乃觀察（Cu，Ni)6Sn5金屬間化合物之結晶構造者 。（Cu，Ni)6Sn5金屬間化合物之樣品係以重量％比，使 Sn-0.7Cu-0.05Ni合金，以約300°C均一地融熔之後使其放 置凝固者，從電子束解析圖形及任意5處進行元素分析。 φ 對於觀察，使用電場發射透過型電子顯微鏡（Philips公司 製FEG-AEM) ’將加速電壓作爲20〇keV進行運轉。結晶 構造觀察及元素分析係經由高倍率結晶晶格觀察（x640k)、 640mm之相機長的電子束解析圖形，奈米探針元素分析 (EDS)。如在圖3所了解地，存在有Ni之情況，結晶構造 乃六方晶。另外，結晶內之Ni濃度係平均約9at%。 在如此之見解中，發明者係對於Sn-Cu而言，如適量 添加Ni ’即使金屬間化合物之Cu6Sn5乃經由凝固而溫度 下降之情況’亦確認到維持六方晶，結晶構造乃安定化者 -11 - 201032376 ’實現抑制或迴避從未添加Ni之情況的Cu6Sn5之六方晶 至斜方晶的固相變化者。經由此，在（Cu，Ni)6Sn5層中， 控制在固相變化時之破損或破裂之產生，或迴避含有偏應 力者。 另外，如於圖4各所示，（Cu，Ni)6Sn5係如比較對象 之Cu6Sn5，結晶並非粗大而是細的構造，對於表面組織構 造亦爲細密之故，可增加全體表面積，可增多Li離子之 儲存量，進而可促進反應速度者。更且，亦在圖4之剖面 相片了解到，（Cu，Ni)6Sn5係亦未確認到如比較對象之 Cu6Sn5之斷裂的產生。 然而，對於於Cu等之電極表面，由浸漬法或回流法 ，形成（Cu，Ni)6Sn5金屬間化合物層之情況，嚴格來說， 成爲從接近於Cu之部分朝向表面側，Cu —(Cu，Ni)6Sn5 金屬間化合物—Sn合金組成乃具有梯度而加以形成之故， 表面係成爲富有Sn之狀態。因此，適宜除去Sn，但因應 必要，以如蝕刻等從以往所知之方法去除而爲充分。 更且，在本實施型態中，於（Cu，Ni)6Sn5金屬間化合 物之更加表面，因應必要而形成碳石墨層，但其方法係由 採用在塗布碳石墨之後進行燒成等以往之方法者而爲充分 。必要則是碳石墨層乃於（Cu，Ni)6Sn5金屬間化合物層之 更加表面側，牢固地固定者，不問其固定方法。 實施例1 比較作爲負電極而使Cu 6 Sn5金屬間化合物固定者， -12- 201032376 與使本發明之（Cu，Ni)6Sn5金屬間化合物固定者，顯示利 用本發明之負電極構造情況之充放電的特性。圖5係採用 本發明之負電極者，圖6係採用CU6Sxi5金屬間化合物者 。各負電極係於20mmx50mmx〇.lmm之尺寸的銅板，塗布 JIS標準焊劑B，10秒浸漬於以255 °C融熔之焊料，對於 銅板表面係進行焊料電鍍，在洗淨石墨之後，使用蝕刻液 溶解去除焊料，作爲呈於表面露出金屬間化合物地得到。 φ 爲了做成鋰電池之環境，調配電解液，但作爲溶質，將六 氟磷酸鋰（LiPF6)，作爲溶劑，將乙烯碳酸酯（EC)與二甲基 碳酸酯（DMC)之混合溶劑，調配成濃度lmol /dm3而使用 。另外，對於正極及隔板係分解市售之A&TB公司製鋰離 子電池（LAB503 759C2)而取出各自而使用。爲了做確認， 以SEM-EDX觀察正極，確認到集電體乃A1，正極物質乃 鈷酸鋰。 實驗係爲了求精密而在處理室內之氮素環境下進行， Φ 經由圖9之電路而確認輸出電壓。在圖9中，1係測試樣 品的電池’ 2係1 OOkD之電阻，3係切換開關，4係橫河 電機製之電壓記錄計（LIM210E)、5係高砂製作所製之電 源（ZX-400L)。並且，對於電池1而言進行充電，在充電 完成後，操作切換開關3而連接電阻2與電池1。在電壓 下降至2.6V之時點’再次操作切換開關3，對於電池1進 行60秒充電，同樣地操作切換開關3而放電至電阻2側 。將其放電作爲第1周期，重複充放電至50周期。 如此從重複充放電所得到之電壓變化之資料，經由下 -13- 201032376 式求得充放電時之電性容量，圖5，圖6乃顯示每周期之 放電容量。In the case where Cu is operated in the same manner as Ni, the method of manufacturing the metal-iridium electrode for replacement is not limited to the impregnator as described above, and may be a surface of an electrode such as Cu or Cu as a main element. A method of forming a (Cu, Ni) 6Sn5 intermetallic compound may be employed, and a known reflow method or the like may be applied, and the coating, the tape, the foil, the spray, and the like containing the composition of the intermetallic compound described above may be applied. It can be widely used from the conventionally known φ surface treatment method. In particular, in the case of using a copper foil, a solder composed of Sn-Cu-Ni is electroplated on a copper foil, followed by attenuating treatment to form a (Cu, Ni) 6Sn5 intermetallic compound. [Effect of the Invention] The negative electrode structure of the present invention can be obtained without greatly changing the impregnation process of the melted tin known from the prior art. In addition, since the surface φ layer of the electrode structure is a hexagonal (Cu, Ni) 6Sn5 intermetallic compound which does not change during solidification, it is possible to avoid the manufacturing process of the surface layer as much as possible, and to generate cracks inside. Even on the physical side, it can be used as a highly reliable structure. Moreover, since the crystal structure is larger than the hexagonal crystal size of graphite, it can store a large amount of Li ions during charging, and can also control the formation of an expander through the storage of Li ions, as compared with graphite. , can be expected as a long-life battery. [Embodiment] -9 - 201032376 First, the (Cu, Ni) 6Sn5 intermetallic compound layer which precedes the surface layer of the present invention will be described below with respect to the action of the Sn-Cu-Ni alloy. Fig. 1 is a binary phase diagram of Sn-Cu, but the Cu6Sn5 system of the intermetallic compound of Sn and Cu is about 39.1% by weight or less for the copper concentration'. It is known that the solidus temperature is lower than 186 °C. At the junction, Tl-CU6Sn5 is hexagonal crystal on the high temperature side, rT-CiuSns is orthorhombic on the low temperature side, and the solid phase change is observed by hexagonal crystal and orthorhombic crystal. The crystal structure of the hexagonal crystal is called a closed charge, and the volume of the crystal is concentrated to the minimum state. Therefore, when a solid phase change occurs from a hexagonal crystal to an orthorhombic crystal and conversely from an oblique crystal to a hexagonal crystal, a bulk crystal change is simultaneously generated. For example, in the case where the molten Sn-Cu alloy is solidified, the intermetallic compound of Cu6Sn5 precipitated by the temperature drop is not able to avoid a solid phase change when the temperature is lowered to 186 °C or lower. In this case, when the Sn-Cu alloy is used as the negative electrode surface layer of the lithium ion secondary battery, there is a possibility that the Cu6Sn5 after solidification is broken due to the above phenomenon. In addition, even in the case where the phenomenon of cracking does not occur in Cu6Sn5, the bias stress in the case of solid phase change is included, and the external stress such as a slight impact or temperature change is transmitted as a turning machine to disperse the deviatoric stress. And there is a flaw with cracks or breakage. On the other hand, it is known that when Ni is added to Sn-Cu, Cu of Cu6Sn5 of the Ni-based compound and the intermetallic compound are partially replaced to form (Cu, Ni)6Sn5. Further, in the case of the experiment, the concentration of Ni in the (Cu, Ni)6Sn5 of the intermetallic compound is about 2 to 10 at%, and the crystal structure of the intermetallic compound is hexagonal -10- due to the substitution of Cu for Ni. 201032376 In the state of the crystal, even at the normal temperature, the same structure as the Tl-Cu6Sn5 generated at a temperature higher than the change temperature can be confirmed. In this case, it is considered that when Ni is substituted with one of Cu in Cu6Sn5, it contributes to the stability of the crystal structure of the hexagonal crystal. Furthermore, the temperature rise and fall of 186 ° C across the hexagonal and orthorhombic phases, and the temperature rise and fall test at a temperature of 100 ° C to 2 10 ° C at 1 ° C / min to show differential thermal analysis (DSC) When the phase change was investigated, the Ni concentration of (Cu, Ni)6Sn5 was about 4 at%, and the phase change was not induced by 0, that is, the stability of the hexagonal crystal in the high temperature phase was also confirmed. On the other hand, in the DSC measurement of Cu6Sn5 to which Ni was not added under the same conditions, it was confirmed that the change due to the apparent change in the image was generated at around 186 °C. Figure 3 is a graph showing the crystal structure of a (Cu, Ni) 6Sn5 intermetallic compound. The sample of (Cu, Ni)6Sn5 intermetallic compound is a composition of the Sn-0.7Cu-0.05Ni alloy which is uniformly melted at about 300 ° C in a weight-% ratio, and then placed in a solidified image, and analyzed from an electron beam and optionally Elemental analysis was performed at 5 locations. φ For observation, an accelerating voltage was operated at 20 〇 keV using an electric field emission transmission electron microscope (FEG-AEM manufactured by Philips). Crystal structure observation and elemental analysis were performed by high-magnification crystal lattice observation (x640k), 640 mm camera length electron beam analysis pattern, and nano probe elemental analysis (EDS). As is understood from Fig. 3, there is a case where Ni is present, and the crystal structure is hexagonal. Further, the Ni concentration in the crystal was about 9 at% on average. In such an opinion, the inventors have confirmed that the addition of Ni ' even if the temperature of the intermetallic compound Cu6Sn5 is lowered by solidification is reduced for the Sn-Cu, and the crystal structure is stabilized - 11 - 201032376 'Achieve suppression or avoidance of solid phase change of hexagonal to orthorhombic crystal of Cu6Sn5 without the addition of Ni. Thereby, in the (Cu, Ni) 6Sn5 layer, the occurrence of breakage or cracking at the time of solid phase change is controlled, or the person who contains the bias is avoided. Further, as shown in FIG. 4, (Cu, Ni)6Sn5 is a Cu6Sn5 which is a comparative object, and the crystal is not a coarse structure but a fine structure, and the surface structure is also fine, and the entire surface area can be increased, and Li can be increased. The amount of ions stored, which in turn can promote the reaction rate. Further, also in the cross-sectional photograph of Fig. 4, it was found that the (Cu, Ni) 6Sn5 system did not confirm the occurrence of the fracture of the Cu6Sn5 as compared with the object. However, for the electrode surface of Cu or the like, the (Cu, Ni) 6Sn5 intermetallic compound layer is formed by the dipping method or the reflow method, strictly speaking, from the portion close to Cu toward the surface side, Cu — (Cu , Ni) 6Sn5 intermetallic compound—Sn alloy composition is formed by a gradient, and the surface system is in a state rich in Sn. Therefore, it is preferable to remove Sn, but it is necessary to remove it by a conventionally known method such as etching. Further, in the present embodiment, a carbon graphite layer is formed on the surface of the (Cu, Ni)6Sn5 intermetallic compound as necessary, but the method is a conventional method such as baking after coating carbon graphite. The person is full. It is necessary that the carbon graphite layer is on the more surface side of the (Cu, Ni) 6Sn5 intermetallic compound layer and is firmly fixed, regardless of the fixing method. Example 1 Comparison of a Cu 6 Sn5 intermetallic compound as a negative electrode, -12-201032376, and fixing of a (Cu, Ni)6Sn5 intermetallic compound of the present invention, showing the use of the negative electrode structure of the present invention Characteristics of discharge. Fig. 5 shows the use of the negative electrode of the present invention, and Fig. 6 shows the use of the CU6Sxi5 intermetallic compound. Each negative electrode is coated on a copper plate of 20 mm x 50 mm x 〇.lmm size, coated with JIS standard flux B, immersed in solder 255 ° C for 10 seconds, solder plated on the surface of the copper plate, and used after etching graphite. The solder is dissolved and removed, and is obtained as an intermetallic compound exposed on the surface. φ In order to make a lithium battery environment, an electrolyte solution is prepared. However, as a solute, lithium hexafluorophosphate (LiPF6) is used as a solvent, and a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) is blended to a concentration of 1 mol / Use dm3. Further, the positive electrode and the separator were each decomposed and commercially available as a lithium ion battery (LAB503 759C2) manufactured by A&TB Co., Ltd., and used. For confirmation, the positive electrode was observed by SEM-EDX, and it was confirmed that the current collector was A1 and the positive electrode material was lithium cobaltate. The experiment was carried out in a nitrogen atmosphere in the processing chamber for the sake of precision, and Φ confirmed the output voltage via the circuit of Fig. 9. In Fig. 9, the battery of the 1st test sample is a 2 ΩkD resistor, a 3 series switch, a 4 series Yokogawa voltage record meter (LIM210E), and a 5 series high sand production power supply (ZX-400L). . Further, the battery 1 is charged, and after the charging is completed, the changeover switch 3 is operated to connect the resistor 2 and the battery 1. When the voltage drops to 2.6 V, the changeover switch 3 is operated again, and the battery 1 is charged for 60 seconds, and the changeover switch 3 is similarly operated and discharged to the side of the resistor 2. This was discharged as the first cycle, and the charge and discharge were repeated for 50 cycles. Thus, from the data of the voltage change obtained by repeating the charge and discharge, the electrical capacity at the time of charge and discharge was obtained by the following formula -13, 2010, and Fig. 5 shows the discharge capacity per cycle.
A · h-TxV/R T :時間（h) V :電位 R : 100ki2 使用對於於銅板表面固定Cu6Sn5金屬間化合物之負 電極的圖6情況’在第1周期中至2.6V爲止之放電時間 乃294秒’但在第50周期中係縮短爲13〇秒。此係鋰電 池符合於一般’但因負電極乃經由反覆充放電之時而疲勞 。對於此’對於使用固定本發明之負電極的（Cu，Ni)6Sn5 金屬間化合物之負電極的圖5情況，在第1周期中至2.6V 爲止之電壓下降需要42 1秒左右，但在第50周期中，亦 維持243秒的放電時間》從此等的事實，對於使用本發明 之負電極之情況，確認到可維持較未含有Ni之Cu6Sn5金 屬間化合物的負電極爲良好之放電次數者。因而，即使在 利用本發明之負電極之情況，亦可製造充放電型之鋰電池 〇 接著，對於圖5所示之本發明的負電極，於縱軸乃電 壓，於橫軸乃在上述式所示之放電容量，求得圖表乃圖7 ，上方的圖表係顯示1~5周期，下方的圖表係顯示4 6〜5 0 周期。同樣地。對於固定圖6所示之（Cu，Ni)6Sn5金屬間 化合物之負電極，求得圖表乃圖8。以相同條件各進行2 次此等圖7之實驗，和圖8之實驗’求得電位下降至2.6V 之數値而示於表1。 201032376 [表1] 初期(iMh) 50 固期（κ Ah) 放軍容量減少率fOA、 平均(％) SG① 1.59 0.82 48 4 50 SC② 2.53 1.25 50.6 SCN① 3.55 2.13 40.0 33 SGN② 3.16 2.34 25.9 從此表的數値，圖7所示之本發明的負電極（圖中， 以SCN的圈圍住的1與2)之放電容量減少率，對於以平 均33%者而言，固定圖8所示之（Cu，Ni)6Sn5金屬間化合 ® 物之負電極之此係平均爲50% ’本發明的負電極者乃即使 進行反覆充放電，未有容量的減少’而確認到經時劣化少 者。 實施例2 接著，將使用本發明的負電極情況之瞬間的電流値’ 與Cu6Sn5金屬間化合物負電極，以及以往的碳電極同時 測定之圖表，各示於圖10，圖11，圖12。此實驗係因確 認到在極短時間之電性能量的釋放量，並確認到可使用於 對於短時間需要大電流之用途的可能性。 負電極，電解液，以及正極與隔板係以與實施例1同 樣手法取得。並且，爲了求精密而在處理室內之氮素環境 下，經由圖11之電路而進行實驗。在圖13中，與圖9相 同編號係顯示相同構成，但6係岩通計測器製之數位計測 器（VOAC752 1 )，爲了測定電流値而與電池1串連地連接 。然而，數位計測器6之內部電阻係2Ω，電流之測定分 解能係1〇μΑ。 -15- 201032376 可從圖10〜12之各圖表確認到的事實係對於圖12之 碳電極的情況，最大電流係4.3A，對於至1.0A電流値下 降需要2.41秒之情況而言，對於圖11之Cu6Sn5金屬間化 合物之情況，最大電流乃5.2A，至1 ·0Α爲止需要1.64秒 。從此關係，對於負電極採用金屬間化合物之情況，與碳 電極做比較’確認到電性能量係以更短時間加以釋放者。 更且’對於如圖10所示，採用（Cu，Ni)6Sn5金屬間化合 物之本發明的負電極之情況，作爲當初最大電流而可得到 5.5A’下降至1.0A爲止0.98秒之最短時間。從此事實， 在至少此等3種類之負電極，可確認到本發明之負電極乃 可作爲瞬間之電性能量的釋放者。因而，確認到經由採用 本發明之負電極之時，利用於在短時間必須大容量之電性 能量之用途的可能性。 實施例3 爲了確認與本發明之Ni置換而採用之金屬的Co，Mn ^ ，Pd, Zn，Fe 之效果，於 2〇mm><50mmx〇.lmm 尺寸的銅 板，以與實施例1同樣的方法，於表面生成金屬間化合物 ’將此’以和實施例1同樣的實驗進行充放電，如表2地 求取放電容量。 -16- 201032376 [表2] 放電容量減少率(％) SCN 33 SC 50 Co 22.2 Μη 6 Pd 27.6 Zn 31.9 Fe 37.3A · h-TxV/RT : time (h) V : potential R : 100ki2 The case of the negative electrode for fixing the Cu6Sn5 intermetallic compound on the surface of the copper plate is shown as 'the discharge time in the first cycle to 2.6V is 294. Seconds but shortened to 13 seconds in the 50th cycle. This type of lithium battery is in conformity with the general 'but because the negative electrode is fatigued by repeated charge and discharge. For the case of Figure 5 in which the negative electrode of the (Cu, Ni)6Sn5 intermetallic compound to which the negative electrode of the present invention is used is used, the voltage drop in the first cycle to 2.6 V takes about 42 1 second, but in the first In the 50 cycles, the discharge time of 243 seconds was also maintained. From the fact that in the case of using the negative electrode of the present invention, it was confirmed that the negative electrode which can maintain the Cu6Sn5 intermetallic compound not containing Ni is a good discharge number. Therefore, even in the case of using the negative electrode of the present invention, a lithium battery of a charge and discharge type can be manufactured. Next, for the negative electrode of the present invention shown in Fig. 5, the vertical axis is a voltage, and the horizontal axis is in the above formula. The discharge capacity shown is shown in Figure 7. The upper graph shows 1 to 5 cycles, and the lower graph shows 4 6 to 5 0 cycles. Similarly. For the negative electrode of the (Cu, Ni) 6Sn5 intermetallic compound shown in Fig. 6, the graph is obtained as shown in Fig. 8. The experiment of Fig. 7 was carried out twice in the same conditions, and the experiment of Fig. 8 was carried out to find that the potential dropped to 2.6 V and is shown in Table 1. 201032376 [Table 1] Initial (iMh) 50 Solid (κ Ah) Release capacity reduction rate fOA, average (%) SG1 1.59 0.82 48 4 50 SC2 2.53 1.25 50.6 SCN1 3.55 2.13 40.0 33 SGN2 3.16 2.34 25.9 Number from this table値, the discharge capacity reduction rate of the negative electrode of the present invention (in the figure, 1 and 2 surrounded by the circle of SCN) shown in FIG. 7 is fixed as shown in FIG. 8 for an average of 33% (Cu) The negative electrode of the Ni)6Sn5 intermetallic compound is an average of 50%. The negative electrode of the present invention has no decrease in capacity even if it is subjected to reverse charge and discharge, and it is confirmed that the deterioration is small with time. [Example 2] Next, a graph in which the current 値' at the moment of using the negative electrode of the present invention and the Cu6Sn5 intermetallic compound negative electrode and the conventional carbon electrode were simultaneously measured are shown in Fig. 10, Fig. 11, and Fig. 12. This experiment confirms the amount of electrical energy released in a very short time and confirms the possibility that it can be used for applications requiring a large current for a short period of time. The negative electrode, the electrolytic solution, and the positive electrode and the separator were obtained in the same manner as in Example 1. Further, in order to obtain precision, an experiment was conducted through the circuit of Fig. 11 in a nitrogen atmosphere in the processing chamber. In Fig. 13, the same configuration as that of Fig. 9 shows the same configuration, but a digital measuring device (VOAC752 1) made of a 6-series rock flux measuring device is connected in series with the battery 1 for measuring current 値. However, the internal resistance of the digital measuring unit 6 is 2 Ω, and the current measuring and decomposing energy is 1 〇 μ Α. -15- 201032376 The facts that can be confirmed from the graphs of Figures 10 to 12 are for the case of the carbon electrode of Fig. 12, the maximum current is 4.3 A, and for the case where the current 値 drop to 1.0 A requires 2.41 seconds, In the case of the Cu6Sn5 intermetallic compound of 11, the maximum current is 5.2 A, and it takes 1.64 seconds until 1 · 0 。. From this point of view, in the case where the negative electrode is made of an intermetallic compound, it is compared with the carbon electrode to confirm that the electrical energy is released in a shorter time. Further, as shown in Fig. 10, in the case of the negative electrode of the present invention using the (Cu, Ni)6Sn5 intermetallic compound, as the initial maximum current, the shortest time of 0.98 seconds from 5.5 A' to 1.0 A was obtained. From this fact, at least these three types of negative electrodes, it can be confirmed that the negative electrode of the present invention can be used as a releaser of instantaneous electrical energy. Therefore, it has been confirmed that the use of the negative electrode of the present invention is utilized for the use of a large amount of electrical energy in a short period of time. Example 3 In order to confirm the effect of Co, Mn ^ , Pd, Zn, Fe of the metal used for the Ni substitution of the present invention, the copper plate having a size of 2 mm >< 50 mm x 〇.lmm was the same as in Example 1. The method of forming an intermetallic compound on the surface was carried out by charging and discharging in the same manner as in Example 1, and the discharge capacity was determined as shown in Table 2. -16- 201032376 [Table 2] Discharge capacity reduction rate (%) SCN 33 SC 50 Co 22.2 Μη 6 Pd 27.6 Zn 31.9 Fe 37.3
在此等之中，採用錳之負電極係顯示極爲良好之容量 維持，但在其他之置換金屬的Co，Pd，Zn，Fe情況，亦 與C u6 S η 5金屬間化合物負電極之情況作比較時，確認到 即使在進行重複充放電之情況，亦維持良好之效果。然而 ，在此，電鍍於銅板表面之金屬係Sn-0_92Cu-X(X係與Ni 置換之金屬）。提昇設定Cu濃度的理由係因預測Cu與此 等金屬之置換量係較Ni爲多之故，經由較Sn-Cu共晶點 過量添加Cu者。 【圖式簡單說明】 圖1乃Sn-Cu二元相圖。 圖2乃以圖1之二元相圖的四角圍住之部分的擴大圖 〇 圖3乃顯示（Cu，Ni)6Sn5金屬間化合物之結晶構造的 相片。 圖4乃將（Cu ’ Ni)6Sn5金屬間化合物之狀態，與Among these, the negative electrode system using manganese shows extremely good capacity retention, but in the case of other substitution metals of Co, Pd, Zn, Fe, and also with the C u6 S η 5 intermetallic compound negative electrode. In the comparison, it was confirmed that a good effect was maintained even when repeated charge and discharge were performed. Here, however, the metal plated on the surface of the copper plate is Sn-0_92Cu-X (a metal in which X is replaced with Ni). The reason for increasing the Cu concentration is based on the prediction that the substitution amount of Cu and these metals is larger than that of Ni, and Cu is excessively added via the Sn-Cu eutectic point. [Simple description of the diagram] Figure 1 is a binary phase diagram of Sn-Cu. Fig. 2 is an enlarged view of a portion surrounded by the four corners of the binary phase diagram of Fig. 1. Fig. 3 is a photograph showing the crystal structure of the (Cu, Ni) 6Sn5 intermetallic compound. Figure 4 shows the state of the (Cu ‘ Ni)6Sn5 intermetallic compound,
-17- 201032376-17- 201032376
Cu6Sn5之此做比較而顯示之相片。 圖5乃顯示經由本發明之負電極的充放電周期之電壓 變化圖表。 圖6乃顯示將Cu6Sn5金屬間化合物作爲負電極的充 放電周期之電壓變化圖表。 圖7乃顯示本發明之負電極的放電容量減少率圖表。 圖8乃顯示Cu6Sn5金屬間化合物負電極的放電容量 減少率圖表。 圖9乃使用於圖5，圖6之實驗的電路圖。 圖1 0乃顯示經由本發明之負電極的瞬間電流變化圖 表。 圖11乃顯示將（：1168115金屬間化合物作爲負電極的瞬 間電流變化圖表。 圖12乃顯示使用之碳電極之情況的瞬間電流變化圖 表。 圖13乃使用於圖10〜12之實驗的電路圖。 【主要元件符號說明】 1 :電池 2 :電阻 3 ’·切換開關 4 =電壓記錄計 5 :電源 6 :數位計測器The photo displayed by Cu6Sn5 is compared. Fig. 5 is a graph showing the voltage change of the charge and discharge cycle of the negative electrode of the present invention. Fig. 6 is a graph showing the voltage change of the charge and discharge cycle of the Cu6Sn5 intermetallic compound as a negative electrode. Fig. 7 is a graph showing the discharge capacity reduction rate of the negative electrode of the present invention. Fig. 8 is a graph showing the discharge capacity reduction rate of the negative electrode of the Cu6Sn5 intermetallic compound. Figure 9 is a circuit diagram of the experiment used in Figure 5 and Figure 6. Figure 10 is a graph showing the instantaneous current change through the negative electrode of the present invention. Fig. 11 is a graph showing an instantaneous current change of (1168115 intermetallic compound as a negative electrode. Fig. 12 is a graph showing an instantaneous current change in the case of using a carbon electrode. Fig. 13 is a circuit diagram of the experiment used in Figs. [Main component symbol description] 1 : Battery 2 : Resistor 3 '·Switch 4 = Voltage logger 5 : Power supply 6 : Digital Measurer