JP3937515B2 - Non-aqueous secondary battery - Google Patents

Description

本発明の固体微粒子含有層を２層以上有する電池１、４は、比較例の２、３、５に較べ、充放電サイクル性に優れ、かつ高電流を用いた充放電特性に優れ好ましい。
【００５６】
実施例−２
実施例−１記載のスラリーＣ−１の塗布量を５３％に減量した以外は、実施例−１の正極シート−１と同様にして正極シート−２を作製した。実施例−１記載の負極シート−１を作製し、２５０℃１時間の脱水までの工程を実施した。こ脱水後の負極シートに厚さ３０μｍのリチウム金属箔を短冊状に切り１m²あたり１．４ｇずつ両面に貼った。これを負極シート−３とする。正極シートー１を実施例−１と同様に処理し、この正極シート−１、負極シート−１を用いて実施例−１と同様にして電池１１を作製した。この電池を３．３ｖまで充電し４６℃で１３日間放置した。この後４．１Ｖまで定電圧制御で充電した。
実施例−１の負極シート−２，Ａ，Ｂ，Ｃを負極シート−１の代わりに用いた以外は負極シート−３と同様にして負極シート−４，Ｅ，Ｆ，Ｇを作製し下記の負極シート、正極シートの組み合わせで電池１１と同様にして電池１２〜１６を作製した。作製数は各１００本である。これらの電池の平均容量（電池１１を１００とした相対値で表示）と、２５℃１ヶ月後に開路電圧が４．０Ｖ以下になった電池の割合を示した。

本発明の固体微粒子含有層を２層以上有する電池１１、１４は、比較例の１２、１３、１５に較べ、平均容量が高く、４．０Ｖ以下になる電池の割合が小さく好ましい。
【００５７】
実施例−３
負極材料として、化合物−１の代わりに、化合物−２，３，４を用いて実施例−２を繰り返し、同様の結果を得た。
【００５８】
実施例−４
実施例１の負極シート−１を５７mmに裁断し、正極シートは実施例２の正極シート−２を５５．５mmに裁断した。この正負の電極シートを、露点−４０℃以下の乾燥空気中で正極は１８０℃で２時間、負極は２１０℃２時間脱水乾燥した。
この負極シートに、厚み４５μｍのリチウム箔で５５．５mm幅４mmに裁断したものを両面の合剤上に９mmピッチで貼り付けた。リチウム箔の裁断時に切断刃にドデカンを塗りつけ、刃に対するリチウムの付着を防止した。
約１日後に上記のようにして作成した正負の電極を用い、正極シート、微多孔性ポリエチレンフィルムセパレーター、負極シート及びセパレーターの順に積層し、これを巻き込み機で渦巻状に巻回した。この巻き込み機は、正負電極の端部に、アルミニウム、ニッケルのリード板を超音波溶着する部所を有している。
【００５９】
この巻回体を負極端子を兼ねるニッケルメッキを施した鉄製の有底円筒型電池缶に収納した。次にLiPF₆ とLiBF₄ を各々０．９５、０．０５mol 含有し、溶媒がエチレンカーボネート、ジエチルカーボネートの２：８の容量比の混合液からなる電解質を電池缶に注入した。正極端子を兼ねる電池蓋をガスケットを介してカシメて円筒型電池１６を作成した。
この電池を分解し電解液中のトデカンの量を分析したところ、ジエチルカーボネートに対して０．００２重量％であった。
リチウム箔の裁断時にドデカンを使用しないこと以外は電池１６と同様にして電池１７を作成した。また、ドデカンの使用量と負極シートの巻回までの時間を短くすることにより、電解液中のドデカンの量がジエチルカーボネートに対して０．０２８重量％の電池１８、ジエチルカーボネートに対して０．１重量％の電池１９を作成した。
【００６０】
これらの電池を用い、実施例１と同様にしてサイクル性と高電流適性の測定を行った。電池１６と１７はサイクル性と高電流適性いずれにも差がなかった。電池１８は１７よりも高電流適性がやや劣った。特に電池１８は６０℃で保存したときに容量低下することがわかった。電池１９は、サイクル性と高電流適性いずれも著しく劣り、これ以外の電池性能上も好ましくないことがわかった。
【００６１】
【発明の効果】
リチウムを可逆的に吸蔵放出可能な材料を含む正極及び負極、リチウム塩を含む非水電解質、セパレーターから成る非水二次電池において、負極材料を０〜４０重量％しか含まず、絶縁性固体微粒子を含有する層を２層以上有する負極シートを用いると高容量、サイクル性良好、保存性良好な非水二次電池を得ることができる。
【図面の簡単な説明】
【図１】実施例に使用した円筒型電池の断面図を示したものである。
【符号の説明】
８ 正極シート
９ 負極シート
１０ セパレーター
１１ 電池缶
１２ 電池蓋
１３ ガスケット
１４ 安全弁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-aqueous secondary battery with improved productivity, high discharge potential, excellent life and safety.
[0002]
[Prior art]
Non-aqueous secondary batteries using lithium have been extensively developed because of their high capacity. These lithium secondary batteries are usually composed of a positive electrode and a negative electrode containing a material capable of reversibly inserting and extracting lithium, a non-aqueous electrolyte containing a lithium salt, and a separator. However, these non-aqueous secondary batteries have a problem that storage stability deteriorates when an attempt is made to secure a long life and a high capacity at a high discharge potential, which is the original purpose.
[0003]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to improve the productivity of a non-aqueous secondary battery having a high discharge voltage, good charge / discharge cycle characteristics, and excellent storage stability.
[0004]
[Means for Solving the Problems]
  An object of the present invention is to provide a sheet-like positive electrode having at least one layer containing a positive electrode material that is a lithium-containing transition metal compound, at least a layer containing a negative electrode material that is an oxide or chalcogenide capable of occluding and releasing lithium ions. In a non-aqueous secondary battery comprising a sheet-like negative electrode having a single layer, a polyolefin porous separator, and a non-aqueous electrolyte containing a lithium salt,Sheet negative electrodeConsists of three layers coated on the current collector, and two layers far from the current collector contain insulating solid fine particles that do not occlude / release lithium ions,The content of the insulating solid fine particles in the outermost layer is lower than that in the adjacent layerThis is achieved by a non-aqueous secondary battery.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
  Although the aspect of this invention is demonstrated below, this invention is not limited to these.
(1) A sheet-like positive electrode having at least one layer containing a positive electrode material which is a lithium-containing transition metal compound, a sheet having at least one layer containing a negative electrode material which is an oxide or chalcogenide capable of occluding and releasing lithium ions. In a non-aqueous secondary battery comprising a cylindrical negative electrode, a polyolefin porous separator, and a non-aqueous electrolyte containing a lithium salt,Sheet negative electrodeConsists of three layers coated on the current collector, and two layers far from the current collector contain insulating solid fine particles that do not occlude / release lithium ions,The content of the insulating solid fine particles in the outermost layer is lower than that in the adjacent layerA non-aqueous secondary battery characterized by the above.
(2) The two layers far from the current collector of Item 1 are two layers having different contents of insulating solid fine particles that do not occlude / release lithium ions, and the content of the insulating solid fine particles in the outermost layer is The nonaqueous secondary battery according to claim 1, wherein the nonaqueous secondary battery is 5% or more lower than an adjacent layer.
(3) The two layers far from the current collector of Item 1 contain insulating solid fine particles that do not occlude / release lithium ions and a hydrophilic polymer compound, and the hydrophilic polymer compound in the outermost layer The non-aqueous secondary battery according to claim 1, wherein the weight content is higher than that of the adjacent layer.
(4) The two layers far from the current collector of Item 1 include insulating solid fine particles that do not occlude / release lithium ions and conductive particles, and the weight content of the conductive particles in the outermost layer is an adjacent layer. The nonaqueous secondary battery according to claim 1, wherein the nonaqueous secondary battery is higher.
(5) The total amount of insulative solid fine particles in which the two layers far from the current collector of Item 1 contain insulative solid fine particles that do not occlude / release lithium ions, and the electrode material that can occlude / release lithium ions The non-aqueous secondary battery according to claim 1, wherein the non-aqueous secondary battery includes 1% by weight or more and 40% by weight or less based on the weight.
(6) Each of the two layers far from the current collector of Item 1 has a thickness of 0.1 μm or more and 40 μm or less. Next battery.
(7) The non-aqueous secondary battery according to any one of claims 1 to 6, wherein the insulating solid fine particles are inorganic oxides.
[0006]
(8)The inorganic oxide is Al ₂ O ₃ , As ₄ O ₆ , B ₂ O ₃ , BaO, BeO, CaO, Li ₂ O, K ₂ O, Na ₂ O, In ₂ O ₃ , MgO, Sb ₂ O ₅ , SiO ₂ , SrO, ZrO ₂ Item 8. The nonaqueous secondary battery according to Item 7, wherein the nonaqueous secondary battery is at least one selected from the group consisting of:
(9) The nonaqueous secondary battery according to any one of items 1 to 8, wherein lithium ions are electrochemically inserted into the negative electrode material in advance before or / and within the battery.
(10) The lithium ion preliminary insertion method is,The lithium metal foil having a thickness of 10 μm or more and 70 μm or less is pasted on the sheet-like negative electrode.9A non-aqueous secondary battery according to 1.
(11) The term wherein the amount of the lithium metal foil is 10 mg or more and 2 g or less per 1 g of the negative electrode material.10A non-aqueous secondary battery according to 1.
(12) Any one of Items 1 to 11, wherein the negative electrode material is an oxide or a chalcogenide mainly composed of at least one element selected from Group 13, Group 14 and Group 15 elements of the Periodic Table The non-aqueous secondary battery according to claim 1.
(13) The non-electrode according to any one of Items 1 to 12, wherein the negative electrode material is an oxide or a chalcogenide mainly composed of at least one element selected from Pb, Sn, Ge, or Si. Water secondary battery.
(14) The nonaqueous secondary battery according to any one of Items 1 to 13, wherein the negative electrode material is an amorphous oxide mainly composed of Sn.
(15) The negative electrode material is represented by the general formula (1)
SnM¹aM²bOs (1)
(Where M¹Is at least one element selected from Al, B, P, Ge, Si, M²Represents at least one element selected from Group 1 elements, Group 2 elements, Group 3 elements and halogen elements in the periodic table, a is a number from 0.2 to 2, and b is from 0.01 to 1. In the following numbers, 0.2 <a + b <2, and s represents a number from 1 to 6. 15. The nonaqueous secondary battery according to any one of Items 1 to 14, wherein the nonaqueous secondary battery is an amorphous oxide represented by
[0007]
Hereinafter, the present invention will be described in detail. The electrode sheet of the present invention has at least two layers containing insulating solid fine particles that do not substantially occlude / release lithium ions. Examples of these layer configurations of the present invention are, from the current collector side, an electrode material coating layer capable of inserting and extracting lithium ions, a layer containing insulating fine particles, and an outermost layer containing insulating fine particles.
Hereinafter, a layer containing insulating solid fine particles that do not substantially occlude / release lithium ions (hereinafter referred to as an auxiliary layer, which is distinguished from a coating layer of an electrode material) will be described. The thickness of these auxiliary layers is preferably 0.1 to 40 μm, and more preferably 0.5 to 20 μm.
The content of the insulating solid fine particles that do not substantially occlude / release lithium ions is preferably 10 to 90% by weight, and more preferably 20 to 80% by weight. It is preferable that the content of the layer far from the current collector is smaller than the layer on the near side. The difference is preferably 5% by weight or more, and more preferably 10% by weight or more.
The auxiliary layer of the present invention can contain an electrode material described later as long as it does not affect the electrode reaction. The addition amount of these electrode materials is 1% by weight or more and 40% by weight or less, more preferably 2% by weight or more and 20% by weight with respect to insulating solid fine particles that do not substantially occlude / release lithium ions. % Or less.
[0008]
  Examples of the insulating solid fine particles that substantially do not occlude / release lithium ions include metal, non-metallic element carbides, silicides, nitrides, sulfides, and oxide particles. Among carbides, silicides, and nitrides, SiC, aluminum nitride (AlN), BN, and BP are preferably highly insulating and chemically stable. Particularly, SiC using BeO, Be, and BN as a sintering aid is preferable. Particularly preferred. Among chalcogenides, oxides are preferable, and oxides that are not easily oxidized or reduced are preferable. These oxides include Al₂O₃, As₄O₆, B₂  O₃  , BaO, BeO, CaO, Li₂O, K₂O, Na₂O, In₂O₃, MgO, Sb₂O₅, SiO₂, SrO,ZrO ₂ Is given. Among these, Al₂O₃, BaO, BeO, CaO, K₂O, Na₂O, MgO, SiO₂, SrO,ZrO ₂ Is particularly preferred. These oxides may be single or complex oxides. Preferred compounds as the composite oxide include mullite (3Al₂O₃・ 2SiO₂), Steatite (MgO.SiO)₂), Forsterite (2MgO · SiO₂), Cordierite (2MgO · 2Al)₂O₃・ 5SiO₂And the like. These inorganic compound particles are used as particles having a size of 0.1 μm or more and 20 μm or less, particularly preferably 0.2 μm or more and 15 μm or less, by a method such as control of production conditions or grinding.
[0009]
The auxiliary layer of the present invention contains, in addition to the above-mentioned insulating solid fine particles, a hydrophilic polymer compound, conductive particles, and an electrode material capable of occluding / releasing lithium ions, which will be described later, as necessary. Can do.
Examples of the hydrophilic polymer compound include polysaccharides such as starch, polyvinyl alcohols having different saponification degrees, cellulose derivatives such as carboxymethyl cellulose, polyvinyl pyrrolidone, and polyethylene oxide. Particularly preferred is carboxymethylcellulose. The addition amount of the hydrophilic polymer compound is 0.1% by weight or more and 20% by weight or less, and more preferably 0.3% by weight or more and 10% by weight or less with respect to the weight of the auxiliary layer. The content of the outermost layer is higher than that of the adjacent layer, 1.1 times or more, and more preferably 1.3 times or more.
[0010]
The conductive particles may be anything as long as they are electron conductive materials that do not cause a chemical change in a configured battery. Natural graphite (scale-like graphite, scale-like graphite, earth-like graphite, etc.), artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber or metal (copper, nickel, aluminum, silver, etc.) powder, metal fiber or A conductive material such as a polyphenylene derivative may be included as one type or a mixture thereof. Among these, graphite and acetylene black are particularly preferable. The added amount is preferably 1 to 50% by weight, more preferably 2 to 30% by weight, and particularly preferably 3 to 15% by weight. The added amount of the outermost layer is preferably 1.2 times or more higher than the adjacent layer, and more preferably 1.4 times or more higher.
[0011]
The content of the electrode material, particularly the negative electrode material described later, is preferably 0 to 40% by weight, more preferably 0 to 20% by weight, and still more preferably 0 to 10% by weight.
In addition to the above, a binder such as a fluororesin described later may be added to the auxiliary layer of the present invention.
[0012]
The auxiliary layer of the present invention may be applied to either the positive electrode or the negative electrode, or may be applied to both the positive electrode and the negative electrode. In addition, when the positive electrode or the negative electrode is formed by applying a mixture on both sides of the current collector, the protective layer may be applied on both sides or only on one side. Also good. However, it is necessary to coat either one of the positive electrode and the negative electrode that oppose each other via the separator. A form in which an auxiliary layer is formed on the negative electrode is particularly preferable.
The auxiliary layer coating method may be a sequential method in which a protective layer is sequentially coated after a mixture containing a material capable of reversibly occluding and releasing lithium on a current collector, or a mixture layer And a simultaneous application method in which a protective layer is applied simultaneously.
[0013]
The negative electrode material used in the present invention is an oxide or chalcogenide capable of inserting and extracting lithium.
In particular, the negative electrode material is preferably an oxide or chalcogenide mainly composed of at least one element selected from Group 13, 14 and 15 elements of the Periodic Table.
Furthermore, the negative electrode material is preferably an oxide or chalcogenide mainly composed of at least one element selected from Pb, Sn, Ge, or Si.
[0014]
For example, Ga₂ O_Three , SiO, GeO, GeO₂ , SnO, SnO₂ , PbO, PbO₂ , Pb₂ O_Three , Pb₂ O_Four , Pb_Three O_Four , Sb₂ O_Three , Sb₂ O_Four , Sb₂ O_Five , Bi₂ O_Three , Bi₂ O_Four , Bi₂ O_Five , SnSiO_Three , GeS, GeS₂ , SnS, SnS₂ , PbS, PbS₂ , Sb₂ S_Three , Sb₂ S_Five , SnSiS_Three Etc. These are also complex oxides with lithium oxide, such as Li₂ GeO_Three , Li₂ SnO₂ It may be.
[0015]
These compounds may contain a transition metal, for example, SnMnO.₂ , SnMnO_Three , SnTiO₂ , SnTiO_Three , SnWO_Three , SnWO_Four , SnVO_3.5 , SnVO_4.5 , SnFeO_2.5 , SnFeO_3.5 , SnCoO₂ , SnCoO_Three , SnNiO₂ , SnNiO_Three , SnCuO₂ , SnCuO_Three , SnMoO_Three , SnMoO_Four , SnMoO_Five , SnAgO_1.5 , SnAg_2.5 , GeMnO₂ , GeMnO_Three , GeTiO₂ , GeTiO_Three , GeWO_Three , GeWO_Four , GeVO_3.5 , GeVO_4.5 , GeFeO_2.5 , GeFeO_3.5 , GeCoO₂ , GeCoO_Three , GeNiO₂ , GeNiO_Three , GeCuO₂ , GeCuO_Three , GeMoO_Three , GeMoO_Four , GeMoO_Five , GeAgO_1.5 , GeAg_2.5 , SiMnO₂ , SiMnO_Three , SiTiO₂ , SiTiO_Three , SiWO_Three , SiWO_Four , SiVO_3.5 , SiVO_4.5 , SiFeO_2.5 , SiFeO_3.5 , SiCoO₂ , SiCoO_Three , SiNiO₂ , SiNiO_Three , SiCuO₂ , SiCuO_Three , SiMoO_Three , SiMoO_Four , SiMoO_Five , SiAgO_1.5 , SiAg_2.5 , PbnMnO₂ , PbMnO_Three , PbTiO₂ , PbTiO_Three , PbWO_Three , PbWO_Four , PbVO_3.5 , PbVO_4.5 , PbFeO_2.5 , PbFeO_3.5 , PbCoO₂ , PbCoO_Three , PbNiO₂ , PbNiO_Three , PbCuO₂ , PbCuO_Three , PbMoO_Three , PbMoO_Four , PbMoO_Five , PbAgO_1.5 , PbAg_2.5 Etc. These may be composite oxides with lithium.
[0016]
The complex oxide or complex chalcogenide is preferably mainly amorphous when assembled into a battery.
The term “amorphous” as used herein refers to an X-ray diffraction method using CuKα rays, which has a broad scattering band having an apex from 20 ° to 40 ° as a 2θ value, and has a crystalline diffraction line. Also good. Preferably, the strongest intensity of the crystalline diffraction lines seen at 2θ values of 40 ° or more and 70 ° or less is 500 of the diffraction line intensity at the apex of the broad scattering band seen at 20 ° or more and 40 ° or less of 2θ values. It is preferably not more than twice, more preferably not more than 100 times, particularly preferably not more than 5 times, and most preferably not having a crystalline diffraction line.
[0017]
In the present invention, an amorphous oxide mainly composed of Sn is more preferable, among which the general formula (1)
SnM¹ _aM² _bO_s        (1)
(Where M¹ Is at least one element selected from Al, B, P, Ge, Si, M² Represents at least one element selected from Group 1 elements, Group 2 elements, Group 3 elements and halogen elements in the periodic table, a is a number from 0.2 to 2, and b is from 0.01 to 1. In the following numbers, 0.2 <a + b <2, and s represents a number from 1 to 6. It is preferably an amorphous oxide represented by
[0018]
Examples of the amorphous oxide mainly composed of Sn and the amorphous oxide represented by the general formula (1) include the following compounds, but the present invention is not limited thereto.
SnAl_0.4 B_0.5 P_0.5 K_0.1 O_3.65, SnAl_0.4 B_0.5 P_0.5 Na_0.2 O_3.7 , SnAl_0.4 B_0.3 P_0.5 Rb_0.2 O_3.4 , SnAl_0.4 B_0.5 P_0.5 Cs_0.1 O_3.65, SnAl_0.4 B_0.5 P_0.5 K_0.1 Ge_0.05O_3.85, SnAl_0.4 B_0.5 P_0.5 K_0.1 Mg_0.1 Ge_0.02O_3.83, SnAl_0.4 B_0.4 P_0.4 O_3.2 , SnAl_0.3 B_0.5 P_0.2 O_2.7 , SnAl_0.3 B_0.5 P_0.2 O_2.7 , SnAl_0.4 B_0.5 P_0.3 Ba_0.08Mg_0.0 O_3.26, SnAl_0.4 B_0.4 P_0.4 Ba_0.08O_3.28, SnAl_0.4 B_0.5 P_0.5 O_3.6, SnAl_0.4 B_0.5 P_0.5 Mg_{0 . 1}O_3.7
[0019]
SnAl_0.5 B_0.4 P_0.5 Mg_0.1 F_0.2 O_3.65, SnB_0.5 P_0.5 Li_0.1 Mg_0.1 F_0.2 O_3.05, SnB_0.5 P_0.5 K_0.1 Mg_0.1 F_0.2 O_3.05, SnB_0.5 P_0.5 K_0.05Mg_0.05F_0.1 O_3.03, SnB_0.5 P_0.5 K_0.05Mg_0.1 F_0.2 O_3.03, SnAl_0.4 B_0.5 P_0.5 Cs_0.1 Mg_0.1 F_0.2 O_3.65, SnB_0.5 P_0.5 Cs_0.05Mg_0.05F_0.1 O_3.03, SnB_0.5 P_0.5 Mg_0.1 F_0.1 O_3.05, SnB_0.5 P_0.5 Mg_0.1 F_0.2 O_Three , SnB_0.5 P_0.5 Mg_0.1 F_0.06O_3.07, SnB_0.5 P_0.5 Mg_0.1 F_0.14O_3.03, SnPBa_0.08O_3.58, SnPK_0.1 O_3.55, SnPK_0.05Mg_0.05O_3.58, SnPCs_0.1 O_3.55, SnPBa_0.08F_0.08O_3.54, SnPK_0.1 Mg_0.1 F_0.2 O_3.55, SnPK_0.05Mg_0.05F_0.1 O_3.53, SnPCs_0.1 Mg_0.1 F_0.2 O_3.55, SnPCs_0.05Mg_0.05F_0.1 O_3.53,
[0020]
Sn_1.1 Al_0.4 B_0.2 P_0.6 Ba_0.08F_0.08O_3.54, Sn_1.1 Al_0.4 B_0.2 P_0.6 Li_0.1 K_0.1 Ba_0.1 F_0.1 O_3.65, Sn_1.1 Al_0.4 B_0.4 P_0.4 Ba_0.08O_3.34, Sn_1.1 Al_0.4 PCs_0.05O_4.23, Sn_1.1 Al_0.4 PK_0.05O_4.23, Sn_1.2 Al_0.5 B_0.3 P_0.4 Cs_0.2 O_3.5 , Sn_1.2 Al_0.4 B_0.2 P_0.6 Ba_0.08O_3.68, Sn_1.2 Al_0.4 B_0.2 P_0.6 Ba_0.08F_0.08O_3.64, Sn_1.2 Al_0.4 B_0.2 P_0.6 Mg_0.04Ba_0.04O_3.68, Sn_1.2 Al_0.4 B_0.3 P_0.5 Ba_0.08O_3.58, Sn_1.3 Al_0.3 B_0.3 P_0.4 Na_0.2 O_3.3 , Sn_1.3 Al_0.2 B_0.4 P_0.4 Ca_0.2 O_3.4 , Sn_1.3 Al_0.4 B_0.4 P_0.4 Ba_0.2 O_3.6 , Sn_1.4 Al_0.4 PK_0.2 O_4.6 , Sn_1.4 Al_0.2 Ba_0.1 PK_0.2 O_4.45, Sn_1.4 Al_0.2 Ba_0.2 PK_0.2 O_4.6 , Sn_1.4 Al_0.4 Ba_0.2 PK_0.2 Ba_0.1 F_0.2 O_4.9 , Sn_1.4 Al_0.4 PK_0.3 O_4.65, Sn_1.5 Al_0.2 PK_0.2 O_4.4 , Sn_1.5 Al_0.4 PK_0.1 O_4.65, Sn_1.5 Al_0.4 PCs_0.05O_4.63, Sn_1.5 Al_0.4 PCs_0.05Mg_0.1 F_0.2 O_4.63
[0021]
SnSi_0.5 Al_0.1 B_0.2 P_0.1 Ca_0.4 O_3.1 , SnSi_0.4 Al_0.2 B_0.4 O_2.7 , SnSi_0.5 Al_0.2 B_0.1 P_0.1 Mg_0.1 O_2.8 , SnSi_0.6 Al_0.2 B_0.2 O_2.8 , SnSi_0.5 Al_0.3 B_0.4 P_0.2 O_3.55, SnSi_0.5 Al_0.3 B_0.4 P_0.5 O_4.30, SnSi_0.6 Al_0.1 B_0.1 P_0.3 O_3.25, SnSi_0.6 Al_0.1 B_0.1 P_0.1 Ba_0.2 O_2.95, SnSi_0.6 Al_0.1 B_0.1 P_0.1 Ca_0.2 O_2.95, SnSi_0.6 Al_0.4 B_0.2 Mg_0.1 O_3.2, SnSi_0.6 Al_0.1 B_0.3 P_0.1 O_3.05, SnSi_0.6 Al_0.2 Mg_0.2 O_2.7 , SnSi_0.6 Al_0.2 Ca_0.2 O_2.7 , SnSi_0.6 Al_0.2 P_0.2 O_Three , SnSi_0.6 B_0.2 P_0.2 O_Three , SnSi_0.8 Al_0.2 O_2.9 , SnSi_0.8 Al_0.3 B_0.2 P_0.2 O_3.85, SnSi_0.8 B_0.2 O_2.9 , SnSi_0.8 Ba_0.2 O_2.8 , SnSi_0.8 Mg_0.2 O_2.8 , SnSi_0.8 Ca_0.2 O_2.8 , SnSi_0.8 P_0.2 O_3.1
[0022]
Sn_0.9 Mn_0.3 B_0.4 P_0.4 Ca_0.1 Rb_0.1 O_2.95, Sn_0.9 Fe_0.3 B_0.4 P_0.4 Ca_0.1 Rb_0.1 O_2.95, Sn_0.8 Pb_0.2 Ca_0.1 P_0.9 O_3.35, Sn_0.9 Mn_0.1 Mg_0.1 P_0.9 O_3.35, Sn_0.2 Mn_0.8 Mg_0.1 P_0.9 O_3.35, Sn_0.7 Pb_0.3 Ca_0.1 P_0.9 O_3.35Etc.
[0023]
For the oxide or chalcogenide of the present invention, either a firing method or a solution method can be adopted, but a firing method is more preferable. In the firing method, it is preferable to obtain an amorphous oxide and / or a chalcogenite by thoroughly mixing oxides, chalcogenites or compounds of the corresponding elements and then firing them.
[0024]
As firing conditions, the temperature rise rate is preferably 5 ° C. or more and 200 ° C. or less per minute, the firing temperature is preferably 500 ° C. or more and 1500 ° C. or less, and the firing time is 1 hour. It is preferable that it is 100 hours or less. In addition, the temperature decrease rate is 2 ° C. or more per minute and 10⁷ It is preferable that it is below ℃.
The rate of temperature increase in the present invention is the average rate of temperature rise from “50% of the firing temperature (indicated in ° C.)” to “80% of the firing temperature (indicated in ° C.)”. It is the average rate of temperature drop from reaching “80% of the firing temperature (indicated in degrees Celsius)” to “50% of the firing temperature (indicated in degrees Celsius)”.
The temperature lowering may be cooled in a firing furnace, or taken out of the firing furnace and cooled, for example, in water. In addition, a super rapid cooling method such as a gun method, a Hammer-Anvil method, a slap method, a gas atomization method, a plasma spray method, a centrifugal quenching method, or a melt drag method described on page 217 of ceramics processing (Gihodo Publishing 1987) can also be used. Moreover, you may cool using the single roller method and the double roller method of New Glass Handbook (Maruzen 1991) p.172. In the case of a material that melts during firing, the fired product may be continuously taken out while supplying raw materials during firing. In the case of a material that melts during firing, it is preferable to stir the melt.
[0025]
The firing gas atmosphere is preferably an atmosphere having an oxygen content of 5% by volume or less, and more preferably an inert gas atmosphere. Examples of the inert gas include nitrogen, argon, helium, krypton, and xenon. The most preferred inert gas is pure argon.
[0026]
The average particle size of the negative electrode material used in the present invention is preferably 0.1 to 60 μm. To obtain a predetermined particle size, a well-known pulverizer or classifier is used. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling air flow type jet mill, a sieve, or the like is used. When pulverizing, wet pulverization in the presence of water or an organic solvent such as methanol can be performed as necessary. In order to obtain a desired particle size, classification is preferably performed. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be used both dry and wet.
The chemical formula of the compound obtained by firing can be calculated from an inductively coupled plasma (ICP) emission spectroscopic analysis method as a measurement method and a weight difference between powders before and after firing as a simple method.
[0027]
The negative electrode material of the present invention can contain various elements. For example, it may contain dopants of lanthanoid metals (Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg) and various compounds that increase electron conductivity (for example, compounds of Sb, In, and Nb). . The amount of the compound to be added is preferably 0 to 5 mol%.
[0028]
The positive electrode active material used in the present invention may be a transition metal oxide capable of reversibly inserting and releasing lithium ions, but a lithium-containing transition metal oxide is particularly preferable. Preferred lithium-containing transition metal oxide positive electrode active materials used in the present invention include oxides containing lithium-containing Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, and W. Further, alkali metals other than lithium (elements IA and IIA in the periodic table) and / or Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, B, etc. may be mixed. . The mixing amount is preferably 0 to 30 mol% with respect to the transition metal.
More preferable lithium-containing transition metal oxide positive electrode active materials used in the present invention include lithium compounds / transition metal compounds (wherein transition metals are Ti, V, Cr, Mn, Fe, Co, Ni, Mo, W) It is preferable to synthesize by mixing so that the total molar ratio of at least one selected from (1) is 0.3 to 2.2.
As a particularly preferable lithium-containing transition metal oxide positive electrode active material used in the present invention, a lithium compound / transition metal compound (where the transition metal is at least one selected from V, Cr, Mn, Fe, Co, Ni) It is preferable to synthesize by mixing so that the total molar ratio of) becomes 0.3 to 2.2.
A particularly preferable lithium-containing transition metal oxide positive electrode active material used in the present invention is Lix QOy (where Q is a transition metal mainly containing at least one of Co, Mn, Ni, V and Fe), x = 0. 0.2 to 1.2 and y = 1.4 to 3). As Q, in addition to the transition metal, Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, B, or the like may be mixed. The mixing amount is preferably 0 to 30 mol% with respect to the transition metal.
[0029]
As a more preferred lithium-containing metal oxide positive electrode active material used in the present invention, Li_xCoO₂ , Li_xNiO₂ , Li_xMnO₂ , Li_xCo_aNi_1-aO₂ , Li_zCo_bV_1-bO_z, Li_xCo_bFe_1-bO₂ , Li_xMn₂ O_Four , Li_xMn_cCo_2-cO_Four , Li_xMn_cNi_2-cO_Four , Li_xMn_cV_2-cO_z, Li_xMn_cFe_2-cO_Four , Li_xCo_bB_1-bO₂ , Li_xCo_bSi_1-bO₂ , Li_xMn₂ O_Four And MnO₂ A mixture of Li_2xMnO_Three And MnO₂ A mixture of Li_xMn₂ O_Four , Li_2xMnO_Three And MnO₂ (Where x = 0.2 to 1.2, a = 0.1 to 0.9, b = 0.8 to 0.98, c = 1.6 to 1.96, z = 2.01) To 5).
As a more preferred lithium-containing metal oxide positive electrode active material used in the present invention, Li_xCoO₂ , Li_xNiO₂ , Li_xMnO₂ , Li_xCo_aNi_1-aO₂ , Li_xCo_bV_1-bO_z, Li_xCo_bFe_1-bO₂ , Li_xMn₂ O_Four , Li_xMn_cCo_2-cO_Four , Li_xMn_cNi_2-cO_Four , Li_xMn_cV_2-cO_Four , Li_xMn_cFe_2-cO_Four (Where x = 0.7 to 1.2, a = 0.1 to 0.9, b = 0.8 to 0.98, c = 1.6 to 1.96, z = 2.1-2. .3).
As the most preferable lithium-containing transition metal oxide positive electrode active material used in the present invention, Li_xCoO₂ , Li_xNiO₂ , Li_xMnO₂ , Li_xCo_aNi_1-aO₂ , Li_xMn₂ O_Four , Li_xCo_bV_1-bO_z(Where x = 0.7 to 1.2, a = 0.1 to 0.9, b = 0.9 to 0.98, z = 2.02 to 2.3). Here, said x value is a value before the start of charging / discharging, and it increases / decreases by charging / discharging.
[0030]
The positive electrode active material can be synthesized by a method in which a lithium compound and a transition metal compound are mixed and fired, or by a solution reaction, and the firing method is particularly preferable. The firing temperature used in the present invention may be a temperature at which a part of the mixed compound used in the present invention is decomposed and melted, and is preferably 250 to 2000 ° C, particularly preferably 350 to 1500 ° C. In firing, it is preferably calcined at 250 to 900 ° C. The firing time is preferably 1 to 72 hours, more preferably 2 to 20 hours. The raw material mixing method may be dry or wet. Moreover, you may anneal at 200 to 900 degreeC after baking.
The firing gas atmosphere is not particularly limited and can be either an oxidizing atmosphere or a reducing atmosphere. For example, in the air or a gas whose oxygen concentration is adjusted to an arbitrary ratio, hydrogen, carbon monoxide, nitrogen, argon, helium, krypton, xenon, carbon dioxide, or the like can be given.
[0031]
In synthesizing the positive electrode active material of the present invention, a method of chemically inserting lithium ions into the transition metal oxide is preferably a method of synthesizing lithium metal, a lithium alloy or butyl lithium by reacting with the transition metal oxide. .
The average particle size of the positive electrode active material used in the present invention is not particularly limited, but is preferably 0.1 to 50 μm. Although it does not specifically limit as a specific surface area, it is 0.01-50m in BET method²/ G is preferred. The pH of the supernatant when 5 g of the positive electrode active material is dissolved in 100 ml of distilled water is preferably 7 or more and 12 or less.
To obtain a predetermined particle size, a well-known pulverizer or classifier is used. For example, a mortar, a ball mill, a vibration ball mill, a vibration mill, a satellite ball mill, a planetary ball mill, a swirling air flow type jet mill, a sieve, or the like is used.
The positive electrode active material obtained by firing may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.
[0032]
The combination of the negative electrode material and the positive electrode active material used in the present invention is preferably a compound represented by the general formula (1) and Li_xCoO₂ , Li_xNiO₂ , Li_xCo_aNi_1-aO₂ , Li_xMnO₂ , Li_xMn₂ O_Four Or Li_xCo_bV_1-bO_z(Where x = 0.7 to 1.2, a = 0.1 to 0.9, b = 0.9 to 0.98, z = 2.02 to 2.3) and high discharge A nonaqueous secondary battery having excellent voltage and high capacity and charge / discharge cycle characteristics can be obtained.
[0033]
The equivalent amount of lithium inserted into the negative electrode material of the present invention is 3 to 10 equivalents, and the usage ratio with the positive electrode active material is determined according to this equivalent amount. It is preferable to use a ratio of 0.5 to 2 times the usage ratio based on this equivalent. When the lithium supply source is other than the positive electrode active material (for example, lithium metal, alloy, butyl lithium, etc.), the usage amount of the positive electrode active material is determined in accordance with the lithium release equivalent of the negative electrode material. Also at this time, it is preferable to use the ratio of the amount used based on this equivalent by multiplying the coefficient by 0.5 to 2 times.
[0034]
When lithium is inserted into the negative electrode from a lithium supply source other than the positive electrode in advance, the lithium supply source includes lithium metal, lithium alloy (Al, Al—Mn, Al—Mg, Al—Sn, Al—In, Al It is preferable to use a foil or metal powder of an alloy of -Cd and lithium. These metal foils and the like may be positioned directly on the negative electrode mixture or via the protective layer of the present invention. Moreover, you may locate on the electrical power collector without a negative mix. A thin foil of about 20 μm may be uniformly applied, or a thicker foil may be partially arranged. The thickness of the foil can be determined from the amount that is naturally inserted into the negative electrode after the battery is formed.
[0035]
A conductive agent, a binder, a filler, or the like can be added to the electrode mixture. The conductive agent may be anything as long as it is an electron conductive material that does not cause a chemical change in the constructed battery. Usually, natural graphite (such as scaly graphite, scaly graphite, earthy graphite), artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber or metal (copper, nickel, aluminum, silver, etc.) powder, metal Conductive materials such as fibers or polyphenylene derivatives can be included as one type or as a mixture thereof. The combined use of graphite and acetylene black is particularly preferred. The addition amount is preferably 1 to 50% by weight, particularly preferably 2 to 30% by weight. In the case of carbon or graphite, 2 to 15% by weight is particularly preferable.
[0036]
The binder is usually starch, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, diacetyl cellulose, polyvinyl chloride, polyvinyl pyrrolidone, tetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, ethylene-propylene-di. Enter polymers (EPDM), sulfonated EPDM, styrene butadiene rubber, polybutadiene, fluoro rubber, polyethylene oxide and other polysaccharides, thermoplastic resins, rubber elastic polymers, and the like are used as one kind or a mixture thereof. Moreover, when using the compound containing a functional group which reacts with lithium like a polysaccharide, it is preferable to add the compound like an isocyanate group and to deactivate the functional group, for example. The amount of the binder added is preferably 1 to 50% by weight, and particularly preferably 2 to 30% by weight.
Any filler can be used as long as it is a fibrous material that does not cause a chemical change in the constructed battery. Usually, olefin polymers such as polypropylene and polyethylene, fibers such as glass and carbon are used. Although the addition amount of a filler is not specifically limited, 0 to 30 weight% is preferable.
[0037]
In using the negative electrode material of the present invention in a non-aqueous secondary battery system, an aqueous dispersion mixture paste containing the compound of the present invention is applied and dried on a current collector, and the pH of the aqueous dispersion mixture paste is It is preferably 5 or more and less than 10, more preferably 6 or more and less than 9. In addition, it is preferable that the temperature of the water-dispersed paste is kept at 5 ° C. or higher and lower than 80 ° C., and is applied onto the current collector within 7 days after the paste is prepared.
[0038]
As the separator, a material having a large ion permeability, a predetermined mechanical strength, and an insulating microporous or gap is used. Furthermore, in order to improve safety, it is necessary to have a function of blocking the current by closing the gaps at 80 ° C. or higher to increase resistance. The closing temperature of these gaps is 90 ° C. or higher and 180 ° C. or lower, more preferably 110 ° C. or higher and 170 ° C. or lower.
The method of creating the gap varies depending on the material, but any known method may be used.
In the case of a porous film, the shape of the hole is usually circular or elliptical, and the size is 0.05 μm to 30 μm, preferably 0.1 μm to 20 μm. Furthermore, it may be a rod-like or irregular-shaped hole as in the case of making by a stretching method or a phase separation method. In the case of cloth, the gap is a gap between fibers and depends on how to make a woven or non-woven fabric. The proportion of these gaps, that is, the porosity, is 20% to 90%, preferably 35% to 80%.
[0039]
The separator of the present invention is a cloth such as a microporous film, a woven fabric or a non-woven fabric having a thickness of 5 μm to 100 μm, more preferably 10 μm to 80 μm. Nonwoven fabrics and woven fabrics have a thread diameter of 0.1 to 5 μm, polyethylene, ethylene-propylene copolymer, ethylene-butene 1 copolymer, ethylene-methylbutene copolymer, ethylene-methylpentene copolymer, polypropylene Those made of polyfluorinated ethylene fiber yarn are preferred. Among films, woven fabrics and nonwoven fabrics, polyolefin porous films are particularly preferred, and examples thereof include microporous separators made of polyethylene and polypropylene.
The polyolefin microporous separator of the present invention preferably contains at least 20% by weight or more of an ethylene component, and particularly preferably contains 30% by weight or more.
Examples of components other than ethylene include propylene, butene, hexene, ethylene fluoride, vinyl chloride, vinyl acetate, and acetalized vinyl alcohol, with propylene and ethylene fluoride being particularly preferred.
The microporous separator of the present invention may be a copolymer as long as it contains polyolefin, and is preferably made of an ethylene-propylene copolymer or an ethylene-butene copolymer. Furthermore, a mixture may be sufficient and what was made by mixing and melt | dissolving polyethylene and a polypropylene and polyethylene and polytetrafluoroethylene is also preferable.
These separators may be a single film or a composite film. In particular, a laminate in which two or more kinds of microporous films having different pore diameters, porosity, blockage temperature, and the like are laminated, particularly a two-layer type separator and a three-layer type separator are preferable. Also, a composite of different materials such as a microporous film and a woven fabric may be used.
The separator of the present invention may contain inorganic fibers such as glass fibers and carbon fibers, and inorganic particles such as silicon dioxide, zeolite, alumina and talc. Furthermore, the thing which processed the space | gap and the surface with surfactant, and hydrophilized may be used.
[0040]
Examples of the electrolyte include organic solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethylsulfate. Foxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, methyl propionate, ethyl propionate, phosphate triester, trimethoxymethane, dioxolane derivative, sulfolane, 3- Less aprotic organic solvents such as methyl-2-oxazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, diethyl ether, 1,3-propane sultone With a lithium salt soluble solvent obtained by mixing one or more and in the solvent, for example, LiClO_Four , LiBF_Four , LiPF₆ , LiCF_Three SO_Three , LiCF_Three CO₂ , LiAsF₆ , LiSbF₆ , LiB_TenCl_Ten, Lower aliphatic lithium carboxylate, LiAlCl_Four , LiCl, LiBr, LiI, chloroborane lithium, lithium tetraphenylborate and the like. In particular, a mixture of propylene carbonate or ethylene carbonate and 1,2-dimethoxyethane and / or diethyl carbonate is mixed with LiCF._Three SO_Three LiClO_Four , LiBF_Four And / or LiPF₆ An electrolytic solution containing is preferable. LiBF mixed with ethylene carbonate and diethyl carbonate_Four And / or LiPF₆ An electrolyte solution containing is particularly preferred.
The amount of these electrolytes added to the battery is not particularly limited, but a necessary amount can be used depending on the amount of the positive electrode active material and the negative electrode material and the size of the battery. The concentration of the supporting electrolyte is preferably 0.2 to 3 mol per liter of the electrolytic solution.
[0041]
In addition to the electrolytic solution, the following solid electrolyte can also be used. The solid electrolyte is classified into an inorganic solid electrolyte and an organic solid electrolyte. Well-known inorganic solid electrolytes include Li nitrides, halides, oxyacid salts, and the like. Among them, Li_Three N, LiI, Li_Five NI₂ , Li_Three N-LiI-LiOH, LiSiO_Four LiSiO_Four -LiI-LiOH, xLi_Three PO_Four -(1-x) Li_Four SiO_Four , Li₂ SiS_Three In addition, phosphorus sulfide compounds are effective.
In the organic solid electrolyte, a polyethylene oxide derivative or a polymer containing the derivative, a polypropylene oxide derivative or a polymer containing the derivative, a polymer containing an ion dissociation group, a polymer containing an ion dissociation group, and the above aprotic electrolyte Mixtures and phosphate ester polymers are effective.
Furthermore, there is a method of adding polyacrylonitrile to the electrolytic solution. A method of using an inorganic and organic solid electrolyte in combination is also known.
[0042]
As the separator, an insulating thin film having a large ion permeability and a predetermined mechanical strength is used. Sheets and non-woven fabrics made from olefin polymers such as polypropylene, glass fibers or polyethylene are used because of their organic solvent resistance and hydrophobicity. As the pore diameter of the separator, a range generally used for batteries is used. For example, 0.01 to 10 μm is used. The thickness of the separator is generally used in the battery range. For example, 5 to 300 μm is used.
It is also known to add the following compounds to the electrolyte for the purpose of improving discharge and charge / discharge characteristics. For example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphoric triamide, nitrobenzene derivative, sulfur, quinoneimine dye, N-substituted oxazolidinone and N, N′-substituted imidazolidinone, Ethylene glycol dialkyl ether, quaternary ammonium salt, polyethylene glycol, pyrrole, 2-methoxyethanol, AlCl_Three , Conductive polymer electrode active material monomer, triethylenephosphoramide, trialkylphosphine, morpholine, aryl compounds with carbonyl group, hexamethylphosphoric triamide and 4-alkylmorpholine, bicyclic And tertiary amines, oils (Japanese Patent Laid-Open No. 62-287,580), quaternary phosphonium salts, tertiary sulfonium salts, and the like.
[0043]
In order to make the electrolyte nonflammable, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride chloride can be contained in the electrolyte. In addition, carbon dioxide gas can be included in the electrolyte in order to make it suitable for high-temperature storage. Further, the mixture of the positive electrode and the negative electrode can contain an electrolytic solution or an electrolyte. For example, a method is known in which the ion conductive polymer, nitromethane, or electrolyte is included.
[0044]
The positive and negative electrode current collectors may be anything as long as they are electronic conductors that do not cause a chemical change in the constructed battery. For example, a material obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium, or silver in addition to stainless steel, nickel, aluminum, titanium, carbon, or the like as a material is used for the positive electrode.
In particular, aluminum or an aluminum alloy is preferable. For the negative electrode, in addition to stainless steel, nickel, copper, titanium, aluminum, carbon, etc., the surface of copper or stainless steel treated with carbon, nickel, titanium, or silver, Al-Cd alloy, etc. are used. It is done. In particular, copper or a copper alloy is preferable. Oxidizing the surface of these materials is also used. Further, it is desirable to make the current collector surface uneven by surface treatment. As the shape, a film, a sheet, a net, a punched product, a lath body, a porous body, a foamed body, a molded body of a fiber group, and the like are used in addition to the foil. The thickness is not particularly limited, but a thickness of 1 to 500 μm is used.
[0045]
The battery shape can be applied to any of coins, buttons, sheets, cylinders, flats, corners, and the like. When the shape of the battery is a coin or button, the positive electrode active material or the negative electrode material mixture is mainly used after being compressed into a pellet shape. The thickness and diameter of the pellet are determined by the size of the battery. Moreover, when the shape of the battery is a sheet, cylinder, or corner, the positive electrode active material or the negative electrode material mixture is mainly used after being applied (coated), dried and compressed on the current collector. As a coating method, a general method can be used. Examples thereof include a reverse roll method, a direct roll method, a blade method, a knife method, an extrusion method, a curtain method, a gravure method, a bar method, a dip method, and a squeeze method. Of these, blade method, knife method and extrusion method are preferred. The application is preferably performed at a speed of 0.1 to 100 m / min. Under the present circumstances, the surface state of a favorable coating layer can be obtained by selecting the said application | coating method according to the solution physical property and dryness of a mixture. The application may be performed one side at a time or simultaneously on both sides. The application may be continuous, intermittent, or striped. Although the thickness, length, and width of the coating layer are determined by the size of the battery, the thickness of the coating layer on one side is particularly preferably 1 to 2000 μm in a compressed state after drying.
[0046]
As a method for drying or dehydrating pellets and sheets, a generally adopted method can be used. In particular, it is preferable to use hot air, vacuum, infrared rays, far infrared rays, electron beams and low-humidity air alone or in combination. The temperature is preferably in the range of 80 to 350 ° C, particularly preferably in the range of 100 to 250 ° C. The water content is preferably 2000 ppm or less for the entire battery, and preferably 500 ppm or less for each of the positive electrode mixture, the negative electrode mixture, and the electrolyte in terms of cycleability. As a pressing method for pellets and sheets, a generally adopted method can be used, and a die pressing method and a calendar pressing method are particularly preferable. The pressing pressure is not particularly limited, but is 0.2 to 3 t / cm.² Is preferred. The press speed of the calendar press method is preferably 0.1 to 50 m / min, and the press temperature is preferably room temperature to 200 ° C. The ratio of the negative electrode sheet width to the positive electrode sheet is preferably 0.9 to 1.1, particularly preferably 0.95 to 1.0. The content ratio of the positive electrode active material and the negative electrode material varies depending on the compound type and the mixture formulation, and thus cannot be limited.
[0047]
After the mixture sheet and the separator are overlapped with each other, the sheets are rolled, folded, inserted into the can, the can and the sheet are electrically connected, the electrolyte is injected, and the sealing plate Is used to form a battery can. At this time, the safety valve can be used as a sealing plate. In addition to the safety valve, various conventionally known safety elements may be provided. For example, a fuse, bimetal, PTC element, or the like is used as the overcurrent prevention element. In addition to the safety valve, as a countermeasure against the increase in internal pressure of the battery can, a method of cutting the battery can, a method of cracking the gasket, a method of cracking the sealing plate, or a method of cutting the lead plate can be used. Further, the charger may be provided with a protection circuit incorporating measures against overcharge and overdischarge, or may be connected independently.
In addition, as a measure against overcharging, a method of cutting off current by increasing the battery internal pressure can be provided. At this time, a compound for increasing the internal pressure can be contained in the mixture or the electrolyte. Examples of compounds used to increase internal pressure include Li₂ CO_Three , LiHCO_Three , Na₂ CO_Three NaHCO_Three , CaCO_Three , MgCO_Three And carbonates.
[0048]
For the can and lead plate, a metal or alloy having electrical conductivity can be used. For example, metals such as iron, nickel, titanium, chromium, molybdenum, copper, and aluminum, or alloys thereof are used. As a method for welding the cap, the can, the sheet, and the lead plate, a known method (eg, direct current or alternating current electric welding, laser welding, ultrasonic welding) can be used. As the sealing agent for sealing, a conventionally known compound or mixture such as asphalt can be used.
[0049]
The use of the non-aqueous secondary battery of the present invention is not particularly limited. For example, when mounted on an electronic device, a color notebook computer, a monochrome notebook computer, a pen input computer, a pocket (palmtop) computer, a notebook word processor, Pocket word processor, ebook player, mobile phone, cordless phone, pager, handy terminal, mobile fax, mobile copy, mobile printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, minidisc, electric shaver, Electronic translators, car phones, transceivers, power tools, electronic notebooks, calculators, memory cards, tape recorders, radios, backup power supplies, memory cards, etc. Others for consumer use include automobiles, electric vehicles, motors, lighting equipment, toys, game equipment, road conditioners, irons, watches, strobes, cameras, medical equipment (pacemakers, hearing aids, shoulder massagers, etc.). Furthermore, it can be used for various military use and space use. Moreover, it can also combine with a solar cell.
[0050]
【Example】
Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the examples unless it exceeds the gist of the invention.
Synthesis Example-1
6.7 g of tin monoxide, 10.3 g of stannous pyrophosphate, 2.87 g of α-alumina, 1.7 g of boric anhydride, 1.63 g of cesium carbonate, and 0.73 g of germanium oxide are dry mixed and made of alumina. The mixture was put in a crucible, heated to 500 ° C. at 15 ° C./min in a nitrogen atmosphere, and calcined at 500 ° C. for 3 hours. Thereafter, the temperature was further increased to 1200 ° C. at 15 ° C./min in a nitrogen atmosphere, baked at 1200 ° C. for 12 hours, and then decreased to room temperature at 10 ° C./min. It is taken out from the firing furnace, coarsely pulverized, further pulverized by a jet mill, and negative electrode material SnGe having an average particle diameter of 7 μm_0.07Al_0.4 B_0.5 P_0.5 Cs_0.1 O_3.79(Compound Example 1) was obtained. In the X-ray diffraction method using CuKα ray, it has a broad peak having a peak near 28 ° at 2θ value, and no crystalline diffraction line was observed at 40 ° to 70 ° at 2θ value. .
[0051]
In the same manner, stoichiometric amounts of raw materials were mixed, fired, and pulverized to synthesize Compound Examples 23 and 4. Further, these compounds were those having a broad scattering band having an apex from 20 ° to 40 ° in terms of 2θ value in the X-ray diffraction method using CuKα ray. In addition, when the diffraction line intensity at the apex of the broad scattering band seen from 20 ° to 40 ° in 2θ value is A, and the crystalline diffraction line is seen from 40 ° to 70 ° in 2θ value, the most of them When the strong intensity was B (B = 0 when there was no crystalline diffraction line), the value of B / A was B / A = 0 in the above compounds.
Compound Example-2 SnK_0.07Al_0.4 B_0.3 P_0.5 Cs_0.1 O_3.38
Compound Example-3 SnBa_0.07Al_0.4 B_0.5 P_0.7 Cs_0.1 K_0.1 O_4.27
Compound Example-4 SnMg_0.05Al_0.4 B_0.6 P_0.5 Cs_0.1 O_Three.₈₅
[0052]
Example-1
As a negative electrode material, Compound-1 synthesized in Synthesis Example 1 was used and mixed at a ratio of 86% by weight, flaky graphite 6% by weight, and acetylene black 3% by weight, and further, polyvinylidene fluoride as a binder. 4% by weight of the aqueous dispersion and 1% by weight of carboxymethylcellulose were added and kneaded using water as a medium to obtain a mixture slurry A-1. Further, 85% by weight of α-alumina having a particle size of 1 μm, 10% by weight of scaly graphite, 4% by weight of an aqueous dispersion of polyvinylidene fluoride and 1% by weight of carboxymethyl cellulose in water as a medium and a pH of 10. The mixture was adjusted to 3 and kneaded to prepare slurry B-1. Further, 63% by weight of α-alumina having a particle size of 2 μm, 32% by weight of flake graphite, 2.5% by weight of an aqueous dispersion of polyvinylidene fluoride, 2% by weight of carboxymethylcellulose, and 0.5% by weight of sodium alkylbenzenesulfonate Using water as a medium, the pH was adjusted to 10.7 with lithium hydroxide and kneaded to prepare slurry B-2. B-1 on top of slurry A-1 and B-2 on top of it were coated simultaneously on both sides of a 18 μm thick copper foil by the extrusion method, dried and compression molded with a calendar press, 250 ° C. Was subjected to heat treatment for 20 minutes and cut into a predetermined width and length to produce a strip-shaped negative electrode sheet-1. The thickness of the negative electrode sheet was 128 μm. The thickness of the A-1 layer was 51 μm on one side, the B-1 layer was 3.3 μm, and the B-2 layer was 0.9 μm.
LiCoO as positive electrode material₂ 86.4% by weight, flaky graphite 4% by weight, acetylene black 3% by weight, sodium hydrogen carbonate 0.6% by weight, polytetrafluoroethylene aqueous dispersion 2.5% by weight as a binder, polyvinylidene fluoride 2.5% by weight of an aqueous dispersion and 1% by weight of sodium polyacrylate were added and kneaded using water as a medium to obtain a mixture slurry C-1. In addition, the obtained slurry was applied to both sides of an aluminum foil having a thickness of 15 μm by the same method as described above, dried, subjected to heat treatment at 250 ° C. for 15 minutes, and compression-molded with a calender press to obtain a predetermined width and length. It cut | disconnected and produced the strip-shaped positive electrode sheet-1. And 210-micrometer strip-shaped positive electrode sheet-1 was produced. The ratio of the coating amount of the negative electrode material on the negative electrode sheet-1 and the positive electrode material on the positive electrode sheet-1 per unit area was positive electrode material / negative electrode material = 5.7.
[0053]
Nickel and aluminum lead plates were spot welded to the respective ends of the negative electrode sheet and positive electrode sheet, and then dehydrated and dried at 250 ° C. for 1 hour in dry air having a dew point of −40 ° C. or lower.
Furthermore, a dehydrated and dried positive electrode sheet (8), a microporous polyethylene film separator, a dehydrated and dried negative electrode sheet (9), and a separator (10) were laminated in this order, and this was wound in a spiral shape with a winding machine.
[0054]
The wound body was housed in a nickel-plated iron-bottomed cylindrical battery can (11) that also serves as a negative electrode terminal. LiPF per liter₆ And LiBF_Four In an amount of 0.9 and 0.1 mol each, and an electrolyte composed of a mixed solution of ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl propionate in a volume ratio of 2: 4: 3: 1 was injected into the battery can. . A battery lid (12) having a positive electrode terminal was caulked through a gasket (13) to produce a cylindrical battery. The positive electrode terminal (12) was connected to the positive electrode sheet (8) and the battery can (11) was previously connected to the negative electrode sheet (9) by a lead terminal. FIG. 1 shows a cross section of a cylindrical battery. (14) is a safety valve. This is designated as sample-1.
[0055]
As a comparative example, a negative electrode sheet-A was obtained in the same manner as the negative electrode sheet-1, except that the slurry B-1 and B-2 were not used and only A-1 was applied. Further, a negative electrode sheet-B was obtained in the same manner as the negative electrode sheet-1, except that the slurry B-2 was not used and only A-1 and B-1 were applied.
Instead of α-alumina, negative electrode sheet-2 was prepared in the same manner as negative electrode sheet-1, except that zirconia having a particle size of 2 μm and 3 μm was used for B-1 and B-2, respectively. C was prepared in the same manner.
The charge / discharge conditions are 4.2 to 2.7 V, 1.4 mA / cm.² It was. The results are shown below.
Charging / discharging cycle characteristics: Number of cycles that is 80% of the first capacity
High current suitability; ratio of first discharge capacity when charge / discharge current is 7 mA / first discharge capacity when 1.4 mA

Batteries 1 and 4 having two or more solid fine particle-containing layers of the present invention are excellent in charge / discharge cycle performance and charge / discharge characteristics using a high current, as compared with Comparative Examples 2, 3, and 5.
[0056]
Example-2
A positive electrode sheet-2 was produced in the same manner as the positive electrode sheet-1 of Example-1, except that the coating amount of the slurry C-1 described in Example-1 was reduced to 53%. A negative electrode sheet-1 described in Example-1 was prepared, and the steps up to dehydration at 250 ° C. for 1 hour were performed. This dehydrated negative electrode sheet is cut into a strip of lithium metal foil with a thickness of 30 μm and 1 m.²1.4g per unit was pasted on both sides. This is designated as negative electrode sheet-3. The positive electrode sheet 1 was treated in the same manner as in Example 1, and a battery 11 was produced in the same manner as in Example 1 using the positive electrode sheet-1 and the negative electrode sheet-1. The battery was charged to 3.3v and left at 46 ° C. for 13 days. Thereafter, the battery was charged with constant voltage control up to 4.1V.
A negative electrode sheet-4, E, F, G was prepared in the same manner as the negative electrode sheet-3, except that the negative electrode sheet-2, A, B, C of Example-1 was used instead of the negative electrode sheet-1. Batteries 12 to 16 were produced in the same manner as the battery 11 by combining a negative electrode sheet and a positive electrode sheet. The number of production is 100 each. The average capacity of these batteries (represented as a relative value with the battery 11 as 100) and the percentage of batteries whose open-circuit voltage became 4.0 V or less after 1 month at 25 ° C. are shown.

Batteries 11 and 14 having two or more solid fine particle-containing layers of the present invention have a higher average capacity than that of Comparative Examples 12, 13, and 15 and preferably have a small proportion of batteries having a voltage of 4.0 V or less.
[0057]
Example-3
Example-2 was repeated using compounds-2, 3, and 4 instead of compound-1 as the negative electrode material, and similar results were obtained.
[0058]
Example-4
The negative electrode sheet-1 of Example 1 was cut to 57 mm, and the positive electrode sheet was cut to 55.5 mm of the positive electrode sheet-2 of Example 2. The positive and negative electrode sheets were dehydrated and dried at 180 ° C. for 2 hours and the negative electrode at 210 ° C. for 2 hours in dry air having a dew point of −40 ° C. or less.
To this negative electrode sheet, a 55.5 mm wide 4 mm piece cut with a lithium foil having a thickness of 45 μm was affixed at a pitch of 9 mm on the mixture on both sides. When cutting the lithium foil, dodecane was applied to the cutting blade to prevent lithium from adhering to the blade.
About one day later, using the positive and negative electrodes prepared as described above, a positive electrode sheet, a microporous polyethylene film separator, a negative electrode sheet, and a separator were laminated in this order, and this was wound in a spiral shape with a winding machine. This entrainer has a portion for ultrasonically welding a lead plate made of aluminum or nickel at the ends of positive and negative electrodes.
[0059]
The wound body was housed in an iron-bottomed cylindrical battery can with nickel plating that also serves as a negative electrode terminal. Next, LiPF₆And LiBF_FourIn an amount of 0.95 and 0.05 mol, respectively, and an electrolyte composed of a mixed solution of ethylene carbonate and diethyl carbonate in a volume ratio of 2: 8 was poured into the battery can. A cylindrical battery 16 was produced by crimping the battery lid serving also as the positive electrode terminal through a gasket.
When this battery was disassembled and the amount of todecane in the electrolyte was analyzed, it was 0.002% by weight based on diethyl carbonate.
A battery 17 was prepared in the same manner as the battery 16 except that dodecane was not used when cutting the lithium foil. Further, by shortening the amount of dodecane used and the time until winding of the negative electrode sheet, the battery 18 in which the amount of dodecane in the electrolytic solution was 0.028% by weight with respect to diethyl carbonate, and 0.1% with respect to diethyl carbonate. A 1% by weight battery 19 was prepared.
[0060]
Using these batteries, cycle performance and high current suitability were measured in the same manner as in Example 1. Batteries 16 and 17 had no difference in either cycle performance or high current suitability. Battery 18 was slightly inferior to 17 in terms of high current suitability. In particular, it was found that the capacity of the battery 18 decreased when stored at 60 ° C. It was found that the battery 19 was remarkably inferior in both cycle performance and high current suitability, and was not preferable in terms of other battery performance.
[0061]
【The invention's effect】
In a non-aqueous secondary battery comprising a positive electrode and a negative electrode including a material capable of reversibly occluding and releasing lithium, a non-aqueous electrolyte including a lithium salt, and a separator, the negative electrode material is contained only in an amount of 0 to 40% by weight, and insulating solid fine particles When a negative electrode sheet having two or more layers containing is used, a non-aqueous secondary battery having a high capacity, good cycleability, and good storage stability can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a cylindrical battery used in an example.
[Explanation of symbols]
8 Positive electrode sheet
9 Negative electrode sheet
10 Separator
11 Battery can
12 Battery cover
13 Gasket
14 Safety valve

Claims (15)

A sheet-like positive electrode having at least one layer containing a positive electrode material which is a lithium-containing transition metal compound, a sheet-like negative electrode having at least one layer containing a negative electrode material which is an oxide or a chalcogenide capable of occluding and releasing lithium ions, In a nonaqueous secondary battery comprising a polyolefin porous separator and a nonaqueous electrolyte containing a lithium salt, the sheet-like negative electrode is composed of three layers coated on a current collector, and two layers far from the current collector A non-aqueous secondary battery comprising insulating solid fine particles that do not occlude / release lithium ions, and the content of the insulating solid fine particles in the outermost layer being lower than that of the adjacent layer .   The two layers far from the current collector of claim 1 are two layers having different contents of insulating solid fine particles that do not occlude / release lithium ions, and the content of the insulating solid fine particles in the outermost layer is an adjacent layer. The non-aqueous secondary battery according to claim 1, wherein the non-aqueous secondary battery is lower by 5% or more.   The two layers far from the current collector of claim 1 contain insulating solid fine particles that do not occlude / release lithium ions and a hydrophilic polymer compound, and contain the weight of the hydrophilic polymer compound in the outermost layer. The nonaqueous secondary battery according to claim 1, wherein the rate is higher than that of the adjacent layer.   The two layers far from the current collector of claim 1 include insulating solid fine particles that do not occlude / release lithium ions and conductive particles, and the weight content of the outermost conductive particles is higher than that of the adjacent layer. The non-aqueous secondary battery according to claim 1, wherein the non-aqueous secondary battery is a non-aqueous secondary battery.   The two layers far from the current collector of claim 1 contain insulative solid particles that do not occlude / release lithium ions, and an electrode material that can occlude / release lithium ions is included in the total amount of insulative solid particles. The non-aqueous secondary battery according to claim 1, wherein the non-aqueous secondary battery includes 1 wt% or more and 40 wt% or less.   The non-aqueous secondary battery according to claim 1, wherein the two layers far from the current collector of claim 1 have a thickness of 0.1 μm or more and 40 μm or less. .   The non-aqueous secondary battery according to claim 1, wherein the insulating solid fine particles are inorganic oxides.   The inorganic oxide is Al ₂ O ₃ , As ₄ O ₆ , B ₂ O ₃ , BaO, BeO, CaO, Li ₂ O, K ₂ O, Na ₂ O, In ₂ O ₃ , MgO, Sb ₂ O ₅ , SiO ₂ , SrO, ZrO ₂ The nonaqueous secondary battery according to claim 7, wherein the nonaqueous secondary battery is at least one selected from the group consisting of:   The nonaqueous secondary battery according to any one of claims 1 to 8, wherein lithium ions are inserted in advance into the negative electrode material electrochemically before and / or within the battery. 10. The non-aqueous secondary battery according to claim 9 , wherein a lithium metal foil having a thickness of 10 μm or more and 70 μm or less is attached to the sheet-like negative electrode by the lithium ion preliminary insertion method. The non-aqueous secondary battery according to claim 10 , wherein the amount of the lithium metal foil is 10 mg or more and 2 g or less per 1 g of the negative electrode material.   12. The anode material according to claim 1, wherein the anode material is an oxide or a chalcogenide mainly composed of at least one element selected from Group 13, Group 14 and Group 15 elements. The non-aqueous secondary battery according to item.   13. The non-aqueous two-component film according to claim 1, wherein the negative electrode material is an oxide or a chalcogenide mainly composed of at least one element selected from Pb, Sn, Ge, and Si. Next battery.   The nonaqueous secondary battery according to claim 1, wherein the negative electrode material is an amorphous oxide mainly composed of Sn. The negative electrode material is represented by the general formula (1)
SnM ¹ aM ² bOs (1)
(In the formula, M ¹ is at least one element selected from Al, B, P, Ge, and Si, and M ² is from Group 1 element, Group 2 element, Group 3 element, and halogen element in the periodic table) Represents at least one element selected, a is a number from 0.2 to 2, b is a number from 0.01 to 1, 0.2 <a + b <2, s is a number from 1 to 6 The non-aqueous secondary battery according to any one of claims 1 to 14, wherein the non-aqueous secondary battery is an amorphous oxide represented by.

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