Patent Publication Number: US-2017365843-A1

Title: Anode, battery, and method of manufacturing same

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a division of U.S. patent application Ser. No. 11/277,238 filed Mar. 23, 2006, the entirety of which is incorporated herein by reference to the extent permitted by law. The present invention contains subject matter related to Japanese Patent Application JP 2005-88038 filed in the Japanese Patent Office on Mar. 25, 2005, the entire contents of which being incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an anode having an anode active material layer containing silicon (Si) as an element, a battery using it, and a method of manufacturing the anode and the battery. 
     2. Description of the Related Art 
     In recent years, as mobile devices have been sophisticated and multi-functionalized, a higher capacity of secondary batteries as a power source for these mobile devices has been highly demanded. As a secondary battery to meet such a demand, there is a lithium secondary battery. However, the battery capacity in the case that lithium cobaltate is used for the cathode and graphite is used for the anode, which is currently a typical form for the lithium secondary batteries, is in a saturated state, and attaining a significantly high capacity thereof is in an extremely difficult situation. Therefore, from old times, it has been considered to use metal lithium (Li) for the anode. However, in order to put the anode to practical use, it is necessary to improve precipitation and dissolution efficiency of lithium and to control dendrite precipitation form. 
     Meanwhile, recently, the high capacity anode using silicon or the like has been actively considered. However, in such anodes, when charge and discharge is repeated, the active material is significantly expanded and shrunk, which leads to pulverization and miniaturization of the anode, current collectivity characteristics are lowered, the surface area is increased leading to accelerated decomposition reaction of the electrolytic solution, and the cycle characteristics are excessively poor. Therefore, an attempt to improve the cycle characteristics by coating the anode current collector with silicon particles and then providing heat treatment to sinter the active material layer has been made. 
     For example, in Japanese Unexamined Patent Application Publication No. H11-329433, descriptions are given of the anode, in which silicon particles and a fibrous reinforcement such as silicon dioxide and aluminum oxide are mixed and fired at from 800 deg C. to 1200 deg C. In Japanese Patent Publication No. 2948205, descriptions are given of the anode, in which silicon particles and a binder are mixed and fired at from 600 deg C. to 1400 deg C. Further, in Japanese Unexamined Patent Application Publication No. 2002-75332, descriptions are given of the anode, in which silicon particles and metal powder are mixed and fired. 
     SUMMARY OF THE INVENTION 
     However, there is a disadvantage that in the foregoing methods, the high energy density inherent in silicon may not to be sufficiently utilized, and the cycle characteristics may not to be sufficiently improved. Further, there is another disadvantage that the melting point of silicon is high, and therefore sintering silicon particles with each other needs temperatures around 1000 deg C., leading to higher cost for mass production equipment. 
     In view of the foregoing, in the present invention, it is desirable to provide an anode capable of providing a high capacity and improving the cycle characteristics, a battery using it, and a method of manufacturing the same. 
     In the present invention, it is desirable to provide a method of manufacturing an anode and a method of manufacturing a battery capable of lowering the heating temperatures and reducing cost for manufacturing equipment. 
     According to an embodiment of the present invention, there is provided an anode having an anode current collector and an anode active material layer provided on the anode current collector, in which the anode active material layer has a structure in which active material particles containing silicon and lithium as an element are bound to each other by sintering or fusing. 
     According to an embodiment of the present invention, there is provided a battery including a cathode, an anode, and an electrolyte, in which the anode has an anode current collector and an anode active material layer provided on the anode current collector, and the anode active material layer has a structure in which active material particles containing silicon and lithium as an element are bound to each other by sintering or fusing. 
     According to an embodiment of the present invention, there is provided a method of manufacturing an anode including a step of forming an anode active material layer by forming a precursor layer containing active material particles containing silicon and lithium as an element on an anode current collector, heating the resultant, and thereby binding the active material particles to each other by sintering or fusing. 
     According to an embodiment of the present invention, there is provided a method of manufacturing a battery including a step of forming an anode by forming a precursor layer containing a plurality of active material particles containing silicon and lithium as an element on an anode current collector, heating the resultant, and thereby binding the active material particles to each other by sintering or fusing. 
     According to the anode of the embodiment of the present invention, the active material particles containing silicon and lithium are bound to each other by sintering or fusing. Therefore, the capacity can be improved and pulverization due to extraction and insertion of lithium can be inhibited. Therefore, according to the battery of the embodiment of the present invention, a high capacity can be obtained, and the battery characteristics such as cycle characteristics can be improved. 
     In particular, when the element of the anode current collector is diffused in the anode active material layer, the contact characteristics between the anode active material layer and the anode current collector are improved, and the cycle characteristics can be more improved. 
     Further, when an interlayer for inhibiting diffusion of the element is provided between the anode current collector and the anode active material layer, the element of the anode current collector is inhibited from being excessively diffused in the anode active material layer, and lowering of the capacity can be inhibited. 
     Further, according to the method of manufacturing an anode and the method of manufacturing a battery of the embodiment of the present invention, after the precursor layer containing the active material particles is formed, the resultant is heated. Therefore, even if heating is provided at temperatures lower than 1000 deg C., the active material particles can be sufficiently bound to each other by sintering or fusing. Consequently, the anode and the battery of the embodiment of the present invention can be easily manufactured, the heating temperature can be lowered, and the manufacturing equipment can be an affordable price. Further, a coat can be formed on the surface of the anode, and the capacity loss at an early stage of charge can be inhibited. 
     In particular, when the particles containing silicon are supported by the anode current collector and then lithium is vapor-deposited and thereby lithium is inserted therein, lithium can be easily and uniformly contained therein, and the anode and the battery of the embodiment of the present invention can be more easily manufactured. 
     Other and further objects, features and advantages of the invention will appear more fully from the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross section showing a structure of an anode according to an embodiment of the present invention; 
         FIG. 2  is a cross section showing a modification of the anode shown in  FIG. 1 ; 
         FIG. 3  is a cross section showing a structure of a secondary battery using the anode shown in  FIG. 1 ; 
         FIG. 4  is an exploded perspective view showing a structure of another secondary battery using the anode shown in  FIG. 1 ; 
         FIG. 5  is a cross section showing a structure taken along line I-I of a spirally wound electrode body shown in  FIG. 4 ; 
         FIG. 6  is an SEM photograph showing a surface structure of an anode according to an example of the present invention; and 
         FIG. 7  is an SEM photograph showing a surface structure of an anode according to a comparative example relative to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment of the present invention will be hereinafter described in detail with reference to the drawings. 
       FIG. 1  simply shows a structure of an anode according to an embodiment of the present invention. An anode  10  has, for example, an anode current collector  11  and an anode active material layer  12  provided on the anode current collector  11 . The anode active material layer  12  may be provided on the both faces or the single face of the anode current collector  11 . 
     The anode current collector  11  is preferably made of a metal material containing at least one metal element not forming an intermetallic compound with lithium. When the intermetallic compound is formed with lithium, the anode is expanded and shrunk associated with charge and discharge, structural destruction occurs, and current collectivity is lowered. In addition, ability to support the anode active material layer  12  is lowered, and the anode active material layer  12  is easily fallen off from the anode current collector  11 . As a metal element not forming an intermetallic compound with lithium, for example, copper (Cu), nickel (Ni), titanium (Ti), iron (Fe), and chromium (Cr) can be cited. 
     As a metal material composing the anode current collector  11 , further, a metal material containing a metal element being alloyed with the anode active material layer  12  is preferable. As described later, when the anode active material layer  12  contains silicon as an element, the anode active material layer  12  is largely expanded and shrunk associated with charge and discharge and is easily fallen off from the anode current collector  11 . However, by alloying the anode active material layer  12  with the anode current collector  11  to strongly adhere, such separation can be inhibited. As a metal element not forming an intermetallic compound with lithium and being alloyed with the anode active material layer  12 , that is, as a metal element being alloyed with silicon, copper, nickel, iron can be cited. Specially, copper is preferable since copper provides a sufficient strength and electrical conductivity. 
     The anode current collector  11  may include a single layer or a plurality of layers. In the latter case, the layer contacting with the anode active material layer  12  may be made of a metal material being alloyed with silicon, and other layers may be made of other metal material. 
     As an anode current collector  11 , a thin film being about from 10 μm to 30 μm thick is preferable in order to improve productivity and battery characteristics. However, the anode current collector  11  may be made of a foam metal or a nonwoven of a fibrous metal or the like. 
     The anode active material layer  12  has a structure in which a plurality of active material particles  12 A containing silicon and lithium as an element are bound to each other by sintering or fusing. Thereby, the anode active material layer  12  is three-dimensionally united, and therefore pulverization due to insertion and extraction of lithium can be inhibited. 
     The active material particles  12 A may be made of an alloy of silicon and lithium. Otherwise, the active material particles  12 A may be made of an alloy further containing one or more other elements such as copper, nickel, iron, germanium, titanium, and cobalt. Further, the active material particles  12 A may be partly oxidized or carbonized. However, the silicon content is preferably higher in order to obtain a higher capacity. For example, the silicon content in the anode active material layer  12  is preferably 50 volume % or more. Further, the active material particles  12 A may be monocrystal, polycrystal, amorphous, or in a mixed state thereof. However, plenty of silicon single phase preferably exists in order to improve the capacity. Only one kind of the active material particles  12 A may be used singly or two or more kinds thereof may be used by mixing. 
     The anode active material layer  12  may contain one or more other anode active materials in addition to the active material particles  12 A. Further, the anode active material layer  12  may contain an electrical conductor made of a carbon material, a metal material or the like or a binder. As a binder, known materials may be used. For example, polyvinylidene fluoride, polyamide, polyamideimide, polyimide, a phenol resin, polyvinyl alcohol, or styrene butadiene rubber can be cited. Though the anode  10  can be formed without using the binder, the binder is preferably used in order to improve formability and facilitate handling in the manufacturing steps. Further, in some cases, the binder preferably remains in the anode  10  after the manufacturing steps are finished in order to improve binding characteristics. 
     At least part of the element of the anode current collector  11  is preferably diffused in the anode active material layer  12 . Thereby, contact characteristics between the anode current collector  11  and the anode active material layer  12  can be improved. However, when the diffusion amount is increased, an intermetallic compound of silicon and the element of the anode current collector  11  is formed and the capacity is lowered. Therefore, for example, as shown in  FIG. 2 , an interlayer  13  for inhibiting diffusion of the element may be provided between the anode current collector  11  and the anode active material layer  12 . The interlayer  13  is preferably made of, for example, a high melting point metal material containing molybdenum (Mo) or the like, a material not being alloyed with silicon such as iridium (Ir), an oxide, or a nitride. 
     The anode  10  can be manufactured as follows, for example. 
     (First Manufacturing Method) 
     First, for example, the active material particles  12 A containing silicon and lithium as an element are prepared. The active material particles  12 A, and if necessary an electrical conductor or a binder are mixed by using a disperse medium. Next, the anode current collector  11  is coated with the mixture, the active material particles  12 A are supported, and thereby a precursor layer is formed. It is possible that the interlayer  13  is formed on the anode current collector  11 , and the precursor layer is formed on the interlayer  13 . Subsequently, it is preferable that after the disperse medium is volatilized and removed according to needs, the precursor layer is pressed by a roll pressing machine to obtain a dense layer. 
     After that, the precursor layer is heated, for example, in non-oxidizing atmosphere, the active material particles  12 A are bound to each other by sintering or fusing to form the anode active material layer  12 . The melting point of silicon is originally high about 1400 deg C., and therefore heating should be provided at high temperatures, 1000 deg C. or more for binding silicon particles with each other. However, according to this embodiment, lithium with the melting point of 180 deg C. is compounded, and therefore even if heating is provided at temperatures lower than 1000 deg C., the active material particles  12 A can be sufficiently bound to each other. Further, accordingly, when a binder whose high temperature durability is high is used, part thereof can remain in the anode active material layer  12 . 
     It is possible that an alloy of silicon and other element is used, the composition in the vicinity of the eutectic point thereof is targeted to lower the melting point. In this case, however, there are large adverse effects as follows. For example, lowered silicon content leads to a lowered capacity, or silicon forms a strongly bonded compound with other element, which leads to electrochemical inactive state of lithium. Meanwhile, when lithium is compounded with silicon, capacity lowering does not occur since silicon is not electrochemically inactivated. 
     Further, by the foregoing heating treatment, for example, the element of the anode current collector  11  is diffused in the anode active material layer  12 . Further, for example, a coat is formed on the surface of the anode active material layer  12 , and thereby side reaction other than electrode reaction can be inhibited. 
     The temperature used when heating the precursor layer is preferably equal to or less than the melting point of the anode current collector  11 . For example, when the anode current collector  11  is made of copper or a material mainly containing copper, the temperature is preferably equal to or less than the melting point of copper. When the heating temperature is high, the element of the anode current collector  11  is excessively diffused in the anode active material layer  12 . Specifically, though depending on the lithium content, the heating temperature is, for example, preferably in the range from 350 deg C. to 800 deg C. As a heating method, a vacuum furnace or a gas replacement furnace may be used; a heating roll may be contacted to the precursor layer or a heater may be used; or plasma heating for applying a large current instantly to the base material may be used. Thereby, the anode  10  shown in  FIG. 1  is obtained. 
     (Second Manufacturing Method) 
     Further, instead of using the active material particles  12 A containing silicon and lithium, the anode  10  may be manufactured by using particles containing silicon but not containing lithium. For example, particles containing silicon but not containing lithium and if necessary an electrical conductor or a binder are mixed by using a disperse medium. The anode current collector  11  is coated with the mixture, which is supported. After that, lithium is inserted therein to form a precursor layer. The heating steps after forming the precursor layer are the same as in the first manufacturing method. 
     As a method for inserting lithium, for example, it is preferable that lithium is vapor-deposited and diffused on the surface of the particles containing silicon, which are supported by the anode current collector  11 . Thereby, lithium can be easily and uniformly inserted by diffusion. For vapor deposition, a known method such as resistance heating, induction heating, and electron beam heating can be used. 
     The vapor deposition amount of lithium is preferably under the insertion amount of lithium of the particles containing silicon supported by the anode current collector  11  per unit area. When the vapor deposition amount of lithium is excessive, lithium metal remains on the surface of the anode active material layer  12 , which causes lowering of the battery characteristics. 
     The anode  10  is used for the secondary battery as follows, for example. 
       FIG. 3  shows a structure of the secondary battery. The secondary battery is a so-called coin-type secondary battery, in which the anode  10  contained in a package cup  21  and a cathode  23  contained in a package can  22  are layered with a separator  24  in between. 
     Peripheral edges of the package cup  21  and the package can  22  are hermetically sealed by being caulked through an insulating gasket  25 . The package cup  21  and the package can  22  are respectively made of a metal such as stainless and aluminum. 
     The cathode  23  has, for example, a cathode current collector  23 A and a cathode active material layer  23 B provided on the cathode current collector  23 A. Arrangement is made so that the cathode active material layer  23 B side is opposed to the anode active material layer  12 . The cathode current collector  23 A is made of, for example, aluminum, nickel, and stainless. 
     The cathode active material layer  23 B contains, for example, as a cathode active material, one or more cathode materials capable of inserting and extracting lithium. The cathode active material layer  23 B may contain an electrical conductor such as a carbon material and a binder such as polyvinylidene fluoride according to needs. As a cathode material capable of inserting and extracting lithium, for example, a chalcogenide not containing lithium, or a lithium complex oxide containing lithium can be cited. As a lithium complex oxide, for example, the lithium complex oxide expressed by a general formula, Li x MO 2  is preferable, since thereby a high voltage can be generated and a high energy density can be obtained. M preferably contains one or more transition metal elements, and for example, preferably contains at least one of cobalt and nickel. x varies according to charge and discharge state of the battery, and is generally in the range of 0.05≦x≦1.10. As a specific example of such a lithium containing metal complex oxide, LiCoO 2 , LiNiO 2  or the like can be cited. When such a lithium complex oxide is used, the lithium complex oxide is preferably incorporated in the battery in a state that lithium thereof is insufficient by being extracted therefrom, since lithium is contained in the anode  10 . 
     The cathode  23  can be formed as follows, for example. A mixture is prepared by mixing a cathode active material, an electrical conductor, and a binder. The mixture is dispersed in a disperse medium such as N-methyl-2-pyrrolidone to form mixture slurry. The cathode current collector  23 A made of a metal foil is coated with the mixture slurry, which is dried and compression-molded to form the cathode active material layer  23 B. 
     The separator  24  separates the anode  10  from the cathode  23 , prevents current short circuit due to contact of the both electrodes, and lets through lithium ions. The separator  24  is made of, for example, polyethylene or polypropylene. 
     An electrolytic solution, which is a liquid electrolyte, is impregnated in the separator  24 . The electrolytic solution contains, for example, a solvent and an electrolyte salt dissolved in a solvent. The electrolytic solution may contain an additive according to needs. As a solvent, for example, a nonaqueous solvent such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and vinylene carbonate can be cited. One of the solvents may be used singly, or two or more thereof may be used by mixing. 
     As an electrolyte salt, for example, a lithium salt such as LiPF 6 , LiCF 3 SO 3 , and LiClO 4  can be cited. One of the electrolyte salts may be used singly, or two or more thereof may be used by mixing. 
     The secondary battery can be manufactured by, for example, layering the anode  10 , the separator  24  impregnated with the electrolytic solution, and the cathode  23 , containing the lamination between the package cup  21  and the package can  22 , and caulking the package cup  21  and the package can  22 . 
     In the secondary battery, since lithium is previously contained in the anode  10 , discharge can be started from the first. First, when discharged, for example, lithium ions are extracted from the anode  10 , and inserted in the cathode  23  through the electrolytic solution. Next, when charged, for example, lithium ions are extracted from the cathode  23  and inserted in the anode  10  through the electrolytic solution. At that time, the anode active material layer  12  is largely expanded and shrunk associated with extraction and insertion of lithium. However, in this embodiment, since the active material particles  12 A are bound to each other by sintering or fusing and united three-dimensionally, pulverization thereof is inhibited. 
     The anode  10  according to this embodiment may be used for the following secondary battery. 
       FIG. 4  shows a structure of the secondary battery. In the secondary battery, a spirally wound electrode body  30  on which leads  31  and  32  are attached is contained inside a film package member  41 . Thereby, a small, light, and thin secondary battery can be obtained. 
     The leads  31  and  32  are respectively directed from inside to outside of the package member  41  and derived in the same direction, for example. The leads  31  and  32  are respectively made of, for example, a metal material such as aluminum, copper, nickel, and stainless, and are in a state of thin plate or mesh, respectively. 
     The package member  41  is made of a rectangular aluminum laminated film, in which, for example, a nylon film, an aluminum foil, and a polyethylene film are bonded together in this order. The package member  41  is, for example, arranged so that the polyethylene film side and the spirally wound electrode body  30  are opposed to each other, and the respective outer edges are contacted to each other by fusion bonding or an adhesive. Adhesive films  42  to protect from outside air intrusion are inserted between the package member  41  and the leads  31  and  32 . The adhesive film  42  is made of a material having contact characteristics to the leads  31  and  32  such as a polyolefin resin of polyethylene, polypropylene, modified polyethylene, and modified polypropylene. 
     The package member  41  may be made of a laminated film having other structure, a high molecular weight film such as polypropylene, or a metal film, instead of the foregoing aluminum laminated film. 
       FIG. 5  shows a cross section structure taken along line I-I of the spirally wound electrode body  30  shown in  FIG. 4 . In the spirally wound electrode body  30 , the anode  10  and a cathode  33  are layered with a separator  34  and an electrolyte layer  35  in between and wound. The outermost periphery thereof is protected by a protective tape  36 . 
     The anode  10  has a structure in which an anode active material layer  12  is provide on the both faces of an anode current collector  11 . The cathode  33  also has a structure in which a cathode active material layer  33 B is provided on the both faces of a cathode current collector  33 A. Arrangement is made so that the cathode active material layer  33 B side is opposed to the anode active material layer  12 . The structures of the cathode current collector  33 A, the cathode active material layer  33 B, and the separator  34  are similar to of the cathode current collector  23 A, the cathode active material layer  23 B, and the separator  24  respectively described above. 
     The electrolyte layer  35  is made of a so-called gelatinous electrolyte, in which an electrolytic solution is held in a high molecular weight compound. The gelatinous electrolyte is preferable, since a high ion conductivity can be thereby obtained, and leak of the battery and swollenness of the battery at high temperatures can be thereby prevented. The composition of the electrolytic solution (that is, a solvent and an electrolyte salt) is similar to of the coin-type secondary battery shown in  FIG. 3 . As a high molecular weight material, for example, polyvinylidene fluoride can be cited. 
     The secondary battery can be manufactured, for example, as follows. First, the electrolyte layer  35 , in which the electrolytic solution is held in the high molecular weight compound is formed on the anode  10  and the cathode  33 , respectively. After that, the lead  31  is attached to the end of the anode current collector  11  by welding, and the lead  32  is attached to the end of the cathode current collector  33 A by welding. Next, the anode  10  and the cathode  33  formed with the electrolyte layer  35  are layered with the separator  34  in between to form the lamination. After that, the lamination is wound in the longitudinal direction. The protective tape  36  is adhered to the outermost periphery thereof to form the spirally wound electrode body  30 . Lastly, for example, the spirally wound electrode body  30  is sandwiched between the package members  41 , and outer edges of the package members  41  are contacted by thermal fusion bonding or the like to enclose the spirally wound electrode body  30 . Then, the adhesive films  42  are inserted between the leads  31 ,  32  and the package member  41 . Thereby, the secondary battery shown in  FIG. 4  and  FIG. 5  is completed. 
     The operation of the secondary battery is similar to of the coin-type secondary battery shown in  FIG. 3 . 
     As above, according to this embodiment, since the active material particles  12 A containing silicon and lithium are bound to each other by sintering or fusing, pulverization due to extraction and insertion of lithium can be inhibited without lowering the capacity. Therefore, a high capacity can be obtained, and the battery characteristics such as cycle characteristics can be improved. Further, since lithium is previously contained in the anode  10 , discharge can be started from the first, and the step of charging the battery after assembling the battery can be excluded. Therefore, the manufacturing steps can be simplified, and the manufacturing cost can be lowered. 
     Further, when the element of the anode current collector  11  is diffused in the anode active material layer  12 , the contact characteristics between the anode active material layer  12  and the anode current collector  11  can be improved, and the cycle characteristics can be improved. 
     In addition, when the interlayer  13  is provided between the anode current collector  11  and the anode active material layer  12 , the element of the anode current collector  11  is inhibited from being excessively diffused in the anode active material layer  12 , and lowering of the capacity can be inhibited. 
     Furthermore, according to this embodiment, after the precursor layer containing the active material particles  12 A is formed, heating is provided. Therefore, even if heating is provided at temperatures lower than 1000 deg C., the active material particles  12 A can be sufficiently bound to each other by sintering or fusing. Consequently, the anode  10  and the battery according to this embodiment can be easily manufactured, the heating temperature can be lowered, and the manufacturing equipment can be an affordable price. Further, a coat can be formed on the surface of the anode active material layer  12 , and therefore the capacity loss at an early stage of charge can be inhibited. 
     In particular, when the particles containing silicon are supported by the anode current collector  11  and then lithium is vapor-deposited and thereby lithium is inserted therein, lithium can be easily and uniformly contained therein and the manufacturing can be more facilitated. 
     EXAMPLES 
     Further, specific examples of the present invention will be hereinafter described in detail with reference to the drawings. In the following examples, the symbols used in the foregoing the embodiment are directly and correspondingly used. 
     As Example 1, the anode  10  shown in  FIG. 1  was formed. First, silicon powder with an average particle diameter of 6 μm as particle containing silicon and polyvinylidene fluoride as a binder were mixed at a weight ratio of silicon powder:polyvinylidene fluoride=95:5. The mixture was dispersed in N-methyl-2-pyrrolidone as a disperse medium to obtain slurry. Next, the anode current collector  11  made of a copper foil being 20 μm thick was uniformly coated with the slurry, which was dried to remove the disperse medium, and the coating layer was compression-molded by a roll pressing machine. Subsequently, the anode current collector  11  was mounted on a water-cooled flat pedestal being 200 mm in outer diameter, lithium was vapor-deposited on the coating layer by resistance heating vapor deposition method to form a precursor layer. At that time, as a vapor deposition source, a source in which chips of lithium are put into a crucible made of stainless around which a tungsten wire is wound was used. The vacuum degree was 1×10 −3  Pa. Further, the deposition amount of lithium was adjusted so that the atomicity ratio of silicon and lithium became 50:50. After that, the anode current collector  11  formed with the precursor solution layer was put in a firing furnace and provided with heating treatment for 2 hours at 650 deg C. in the argon atmosphere. Thereby, the anode  10  was formed. 
     As Example 2, the anode  10  was formed as in Example 1, except that Si—Ti alloy with an average particle diameter of 5 μm was used as particle containing silicon. At that time, as Si—Ti alloy, an alloy obtained by mixing silicon powder and titanium powder at an atomicity % of silicon powder:titanium powder=80:20, previously melting the mixture in an arc melting furnace to form an alloy ingot, forming alloy powder therefrom by a single-roll melting and quenching equipment, and pulverizing the alloy powder by using a ball mill was used. 
     As Example 3, the anode  10  was formed as in Example 1, except that silicon monoxide (SiO) powder with an average particle diameter of 7 μm was used as particle containing silicon. 
     As Example 4, the anode  10  was formed as in Example 1, except that the heat treatment time in the firing furnace was 8 hours. 
     As Example 5, the anode  10  was formed as in Example 1, except that after the interlayer  13  made of molybdenum was formed on the surface of the anode current collector  11  made of a copper foil by electron beam vapor deposition method, the precursor layer was formed. 
     As Comparative example 1 relative to the examples, an anode was formed as in Example 1, except that vapor deposition of lithium and heating treatment were not provided. 
     As Comparative example 2, an anode was formed as in Example 1, except that vapor deposition of lithium was not provided. 
     As Comparative example 3, an anode was formed as in Example 1, except that heating treatment was not provided. 
     As Comparative example 4, an anode was formed as in Example 1, except that vapor deposition of lithium was not provided, and the heating temperature in the firing furnace was 1200 deg C. 
     As Comparative example 5, an anode was formed as in Example 1, except that aluminum was vapor-deposited instead of lithium. 
     As Comparative example 6, an anode was formed as in Example 1, except that silicon powder with an average particle diameter of 6 μm as particle containing silicon, indium powder with an average particle diameter of 5 μm as other particle, and polyvinylidene fluoride as a binder were mixed at a weight ratio of silicon powder:indium powder:polyvinylidene fluoride=80:15:5, the mixture was dispersed in N-methyl-2-pyrrolidone as a disperse medium to obtain slurry, by which a coating layer was formed, and lithium was not vapor-deposited. 
     For the formed anodes  10  of Examples 1 to 5 and Comparative examples 1 to 6, the surface was observed by Scanning Electron Microscope (SEM). In Examples 1 to 5, the active material particles  12 A were bound to each other by sintering or fusing. However, in Comparative examples 1 to 6, the particles were not bound to each other by sintering or fusing. As an example, an SEM photograph of Example 4 is shown in  FIG. 6 , and an SEM photograph of Comparative example 2 is shown in  FIG. 7 . Further, for the anodes  10  of Examples 1 to 5, the anode active material layer  12  was analyzed by a scanning analytical electron microscope (SEM-EDX) using a scanning electron microscope and an energy dispersive X-ray spectrometer (EDX) together. Then, it was confirmed that copper as an element of the anode current collector  11  was dispersed in the active material particles  12 A. 
     &lt;Evaluation 1&gt; 
     Coin-type test batteries as shown in  FIG. 3  were fabricated by using the anodes  10  of Examples 1 to 5 and Comparative examples 1 to 6. As a counter electrode, a lithium metal plate being 1.2 mm thick was used. As a separator, a polypropylene film being 25 μm thick was used. As an electrolytic solution, a solution obtained by dissolving LiPF 6  at a concentration of 1 mol/l in a mixed solvent of ethylene carbonate, dimethyl carbonate, and vinylene carbonate at a volume ratio of ethylene carbonate:dimethyl carbonate:vinylene carbonate=30:65:5 was used. 
     For each fabricated test battery, charge and discharge test was performed and the discharge capacity retention ratio at the 50th cycle to the first cycle was obtained. At that time, charge was performed until the battery voltage reached 0 V at a constant current density of 1 mA/cm 2 , and then performed until the current value reached 0.1 mA at a constant voltage of 0 V. Discharge was performed until the battery voltage reached 1.5 Vat a constant current density of 1 mA/cm 2 . The results are shown in Table 1. 
     &lt;Evaluation 2&gt; 
     Coin-type batteries as shown in  FIG. 3  were fabricated by using the anodes  10  of Examples 1 to 5 and Comparative examples 1 to 6. The cathode  23  was fabricated as follows. Lithium cobaltate (LiCoO 2 ) was used as a cathode active material. Lithium cobaltate, carbon black as an electrical conductor, and polyvinylidene fluoride as a binder were mixed at a weight ratio of LiCoO 2 :carbon black:polyvinylidene fluoride=92:3:5. The mixture was dispersed in N-methyl-2-pyrrolidone as a disperse medium to form mixture slurry. After that, the cathode current collector  23 A made of an aluminum foil was coated with the mixture slurry, which was dried to form the cathode  23 . Then, based on the lithium content and the capacity of silicon of the anodes  10  of Examples 1 to 5 and Comparative examples 1 to 6, design was made so that lithium metal was not precipitated on the anode  10  even if fully charged up to 4.2 V. Further, for the separator  24  and the electrolytic solution, a separator and an electrolytic solution similar to of the coin-type test battery fabricated in Evaluation 1 were used. 
     For each fabricated secondary battery, charge and discharge test was performed and the discharge capacity retention ratio at the 100th cycle to the first cycle was obtained. At that time, charge was performed until the battery voltage reached 4.2 V at a constant current density of 1 mA/cm 2 , and then performed until the current value reached 0.1 mA at a constant voltage of 4.2 V. Discharge was performed until the battery voltage reached 2.5 Vat a constant current density of 1 mA/cm 2 . The results are shown in Table 1. 
     &lt;Evaluation 3&gt; 
     Secondary batteries capable of being discharged from the first were fabricated as in Evaluation 2, except that the anodes  10  of Examples 1 to 5 and Comparative example 3 provided with vapor deposition of lithium by resistance heating vapor deposition method were used, and lithium cobaltate (LiCoO 2 ) as a cathode active material from which lithium was partly extracted was incorporated in the battery. At that time, as in the secondary batteries fabricated in Evaluation 2, design was made so that lithium metal was not precipitated on the anode  10  even if fully charged up to 4.2 V. 
     For each fabricated secondary battery, charge and discharge test was performed and the discharge capacity retention ratio at the 100th cycle to the second cycle was obtained. Then, discharge was performed until the battery voltage reached 2.5 V at a constant current density of 1 mA/cm 2 . Charge was performed until the battery voltage reached 4.2 V at a constant current density of 1 mA/cm 2 , and then performed until the current value reached 0.1 mA at a constant voltage of 4.2 V. The results are shown in Table 1. The initial discharge capacities of the secondary batteries using the anodes  10  of Examples 1, 4, and 5 are shown in Table 1 together as a relative value where the value of Example 1 is 100. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                   
                   
                 Initial 
               
               
                   
                   
                   
                 discharge 
               
               
                   
                 Heating treatment 
                   
                 capacity 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 Coating 
                 Vapor 
                 Temperature 
                 Time 
                   
                 Discharge capacity retention ratio (%) 
                 (relative 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 particle 
                 deposition 
                 (deg C.) 
                 (hour) 
                 Interlayer 
                 Evaluation 1 
                 Evaluation 2 
                 Evaluation 3 
                 value) 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 Example 1 
                 Si 
                 Li 
                 650 
                 2 
                 N/A 
                 97 
                 95 
                 91 
                 100  
               
               
                 Example 2 
                 Si—Ti 
                 Li 
                 650 
                 2 
                 N/A 
                 95 
                 92 
                 88 
                 — 
               
               
                   
                 alloy 
               
               
                 Example 3 
                 SiO 
                 Li 
                 650 
                 2 
                 N/A 
                 96 
                 90 
                 91 
                 — 
               
               
                 Example 4 
                 Si 
                 Li 
                 650 
                 8 
                 N/A 
                 98 
                 96 
                 93 
                 72 
               
               
                 Example 5 
                 Si 
                 Li 
                 650 
                 8 
                 Mo 
                 97 
                 96 
                 92 
                 91 
               
               
                 Comparative 
                 Si 
                 N/A 
                 N/A 
                 N/A 
                 N/A 
                 38 
                 30 
                 — 
                 — 
               
               
                 example 1 
               
               
                 Comparative 
                 Si 
                 N/A 
                 650 
                 2 
                 N/A 
                 65 
                 48 
                 — 
                 — 
               
               
                 example 2 
               
               
                 Comparative 
                 Si 
                 Li 
                 N/A 
                 N/A 
                 N/A 
                 49 
                 41 
                 37 
                 — 
               
               
                 example 3 
               
               
                 Comparative 
                 Si 
                 N/A 
                 1200  
                 2 
                 N/A 
                 22 
                 5 
                 — 
                 — 
               
               
                 example 4 
               
               
                 Comparative 
                 Si 
                 Al 
                 650 
                 2 
                 N/A 
                 69 
                 50 
                 — 
                 — 
               
               
                 example 5 
               
               
                 Comparative 
                 Si + In 
                 N/A 
                 650 
                 2 
                 N/A 
                 68 
                 49 
                 — 
                 — 
               
               
                 example 6 
               
               
                   
               
            
           
         
       
     
     As evidenced by Table 1, according to Examples 1 to 5, in which the particles containing silicon were used, lithium was vapor-deposited thereto, heating was provided, and thereby the active material particles  12 A were bound to each other by sintering or fusing, the discharge capacity retention ratio was improved more than in Comparative examples 1, 2, and 4 to 6, in which lithium was not vapor-deposited and Comparative examples 1 and 3, in which heating treatment was not provided. That is, it was found that when the active material particles  12 A containing silicon and lithium were heated, the active material particles  12 A could be sufficiently bound to each other by sintering or fusing and the cycle characteristics could be significantly improved, even if the heating temperature was lowered down to less than 1000 deg C. 
     Further, according to Examples 4 and 5, in which the heating treatment time was lengthened compared to in Example 1, though the cycle characteristics were improved, the initial discharge capacity was lowered. However, in Example 5, in which the interlayer  13  was formed, the lowering degree of the initial discharge capacity was smaller than in Example 4, in which the interlayer  13  was not formed. That is, it was found that when the interlayer  13  was formed, lowering of the capacity could be inhibited. 
     The present invention has been described with reference to the embodiment and the examples. However, the present invention is not limited to the foregoing embodiment and examples, and various modifications may be made. For example, in the foregoing embodiment and examples, descriptions have been given of the case using the electrolytic solution or the gelatinous electrolyte, in which an electrolytic solution is held in a high molecular weight compound as an electrolyte. However, other electrolyte may be used. As other electrolyte, an inorganic conductor containing lithium nitride, lithium phosphate or the like, a high molecular weight solid electrolyte, in which an electrolyte salt is dispersed in a high molecular weight compound having ion conductivity, a mixture of the foregoing and an electrolytic solution and the like can be cited. 
     Further, in the foregoing embodiment and examples, descriptions have been given of the coin-type secondary battery or the spirally wound laminated-type secondary battery. However, the present invention can be similarly applied to a secondary battery such as a cylinder-type battery, a square-type battery, a button-type battery, a thin-type battery, a large-type battery, and a lamination-type battery. In addition, the present invention can be applied to primary batteries in addition to the secondary batteries. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alternations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.