1]This application claims the benefit of priority based on 8.10.2017 Now Korea Patent Application No. 10-2017-0101380 and 07/27/2018 Now Korea Patent Application No. 10-2018-0087814, the literature of the Korea Patent Application all the disclosed contents of which are incorporated as a part hereof.
[2]The present invention relates to a former lithiated method of the secondary battery anode, particularly in the previous step to assemble a lithium secondary battery, by using the inorganic particles in the molten lithium metal with powdered lithium metal - to produce the inorganic compound thin-film then, to a method of pre lithiated by bonding the thin film composite on the cathode.
BACKGROUND
[3]
The price of energy due to the depletion of fossil fuels is rising, while the amplified interest in environmental pollution becomes an indispensable factor for the demand for eco-friendly alternative energy sources, the future life and, in particular, technology development for mobile devices the demand for secondary batteries as an energy source is rapidly increasing as the demand increases.
[4]
[5]
Typically in the form face of the battery in the high and the demand for prismatic secondary batteries or pouch type secondary batteries with a thin thickness can be applied to products such as a mobile phone, the material surface at high energy density, discharge voltage, the lithium ion battery of the output stability, the demand is high for a lithium secondary battery such as a lithium ion polymer battery.
[6]
[7]
In general, secondary batteries are home coating the entire active materials to the surface of the configuration on the positive and negative electrodes, and then by interposing the separator therebetween made of an electrode assembly, a cylindrical or prismatic metal can, or inside the pouch-shaped case of the aluminum laminate sheet of attached, either primarily or impregnated with a liquid electrolyte injected into the electrode assembly, or is manufactured using a solid electrolyte.
[8]
[9]
A cathode active material of a lithium secondary battery has been various forms of carbon-based materials, including the insertion and desorption of lithium available artificial graphite, natural graphite, and hard carbon is applied. Graphite such as natural graphite or artificial graphite of the carbon-based material is lowered to the discharge voltage of lithium compared to the 0.1V, a battery using graphite as a negative electrode active material exhibits a high discharge voltage of 3.6V, the advantage in the energy density of the lithium cell surface provided, and also the most widely used because it ensures a long life of the lithium secondary battery with excellent reversibility.
[10]
[11]
However, there is a case of fabricating an electrode plate of graphite as the active material, a polar plate capacity density becomes low in a low energy density per unit volume of the side plates a problem. In addition, a high discharge voltage tends to occur a side reaction with the graphite and the organic electrolyte solution, there is a risk of fire or explosion due to erroneous operation and the excessive charging of the battery.
[12]
[13]
In order to solve this problem, a negative active material of the oxide being recently developed. The metal-based active material such as Si, Sn has been proposed as a material capable of represents a high-capacity replacement for the lithium metal. Among them, Si has received attention due to low prices and high capacity (4200mAh / g).
[14]
[15]
However, in the case of using a silicon-based negative active material is a major problem arises initial irreversible capacity. In the charging and discharging reaction of the lithium secondary battery, and has a lithium insertion in the cathode discharge from the anode during charging and discharging when there are desorbed from the negative electrode dolahganeunde back to the anode, in the case of a silicon-based negative active severe a change in volume and the surface side reactions during the initial charge a large amount of lithium inserted into the negative electrode not to go back to the positive electrode, and thus there arises a problem of enlarging the initial irreversible capacity. The larger the initial irreversible capacity, there arises a problem that the battery capacity decreases rapidly with cycle.
[16]
[17]
The method for pre lithiated silicon oxide negative electrode including a silicon-based negative active material in order to solve the problem as described above is known. I lithiated method, and a method for pre lithiated a method for producing the electrode and the negative electrode was lithium by a physicochemical method for the negative electrode active material Chemistry electrochemically known.
[18]
[19]
Conventional physical and chemical methods have a problem that had to due to environmental factors that must be carried out at high temperatures pose a risk of fire and explosion, the production cost increases existing electrochemical method can not uniformly control the initial irreversible capacity there was.
[20]
[21]
US Patent Publication No. 2015-0357628 discloses a negative electrode active material in order to improve the efficiency of the electrode with a high specific capacitance, a mixture of ceramic particles in the molten lithium lithium but is disclosed for coating a negative electrode of a ceramic extrusion technology, lithium due to the high reactivity of the metal must be performed for the entire process under inert gas atmosphere, there was a difficult process disadvantage.
[22]
[23]
Therefore, the technology for a method of improving the initial irreversibility, and improves the safety of the battery is necessary to pre lithiated in a manner relatively easy for the negative electrode having a high capacity.
Detailed Description of the Invention
SUMMARY
[24]
The present invention has been conceived to solve the problems of the prior art, in the former lithiated to improve the initial irreversibility of the negative electrode having a high capacity, and to provide a method which more work processes is easy simple and the handling of lithium metal there are those aimed at.
[25]
Further object of the present invention is also to provide a lithiated prior method of improving the safety of the secondary battery.
Problem solving means
[26]
The present invention, a first step to make a mixture added to the inorganic powder in the molten lithium; After extruding the mixture, and cooling the lithium metal in 100 ~ 200㎛ thickness - a second step of preparing an inorganic composite ribbon; A third step of preparing an inorganic composite film-lithium metal by rolling the inorganic composite ribbon, wherein the lithium metal; The former method of lithiated cathode comprises a; and the lithium metal on the surface of the cathode - a fourth step of forming an inorganic compound layer, raised the inorganic composite film of lithium metal.
[27]
According to an appropriate embodiment of the invention, the lithium metal-inorganic material composite film thickness of from 1 to 50㎛.
[28]
According to an appropriate embodiment of the invention, the ceramic powder is alumina (Al 2 O 3 ), titanium dioxide (TiO 2 ), zirconium dioxide (ZrO 2 ), silicon dioxide (Si0 2 ), tin oxide (Sn0 2 ), oxide cerium (Ce0 2 ), magnesium oxide (MgO), calcium oxide (CaO) and yttria (Y oxide 2 O 3 may be alone or in combination of two or more selected from a).
[29]
According to the preferred embodiment of the present invention, the mixing ratio of molten lithium and the inorganic powder is 70 to 85% by volume of lithium, inorganic material of 15 to 30% by volume.
[30]
According to the preferred embodiment of the present invention, the particle size of the inorganic powder is 0.1 to 10㎛.
[31]
According to the preferred embodiment of the present invention, it may be added mixed with a binder in addition to the inorganic powder in the molten lithium solution.
[32]
According to an appropriate embodiment of the invention, the lithium metal-inorganic compound layer is not activated after the initial charge, the remaining lithium metal in the form.
[33]
According to an appropriate embodiment of the invention, the cathode may comprise silicon oxide.
[34]
In another aspect, the present invention provides a negative electrode of a secondary battery manufactured by applying the pre lithiated way, the secondary battery including the cathode.
Effects of the Invention
[35]
The present invention lithium-metal-because the junction to the cathode of the inorganic compound thin film, to minimize the amount of time that lithium is exposed to the atmosphere, the conventional lithium metal-I as coating for inorganic material mixture, because of the high reactivity of lithium metal for applying a mixture slurry there is an effect that improves the problem that lithium is altered in the process.
[36]
The secondary battery negative electrode prepared by the prior lithiated method provided by the present invention has an initial irreversible improved properties, the secondary battery manufactured using such a secondary battery, the negative electrode has a high charge-discharge efficiency.
[37]
In addition, the lithium metal of the present invention an inorganic compound layer is introduced into the cathode, as inserted into the anode active material layer of lithium by the former lithiated is a mineral left in the residue in the multiple layer safety of the battery to protect the cathode surface the effect of improving.
Brief Description of the Drawings
[38]
1 is a schematic view schematically showing a manufacturing process, the first step to the third step of the present invention.
[39]
Figure 2 is a schematic view showing a manufacturing process step 4 of the present invention.
[40]
3 is formed on a lithium metal electrode by a fourth step of the present invention is a view showing the inorganic compound layer and around the lithiated.
[41]
Figure 4 is a lithium metal by pre lithiated of the present invention illustrates the inorganic layer of lithium remain occluded result in electrode from the inorganic compound layer.
Best Mode for Carrying Out the Invention
[42]
Hereinafter, the present invention in detail. The present invention is not limited by the following Examples and Experimental Examples. Examples according to the present invention can be modified in many different forms and the scope of the invention is not to be construed as limited to the embodiments set forth herein. Embodiments of the present invention are provided to more fully illustrate the present invention the technician skilled in the art.
[43]
[44]
I lithiated cathode of a secondary battery according to the present invention includes a first step of making the mixture added to the inorganic powder in the molten lithium; After extruding the mixture, and cooling the lithium metal in 100 ~ 200㎛ thickness - a second step of preparing an inorganic composite ribbon; A third step of preparing an inorganic composite film-lithium metal by rolling the inorganic composite ribbon, wherein the lithium metal; And the lithium metal on the surface of the cathode - a fourth step of forming an inorganic compound layer, raised the inorganic composite film of lithium metal; In that it comprises the features.
[45]
Cathode material initial irreversibility of the lithium ion battery has a major drawback. In particular, the former lithiated (pre-lithiation) before making a cell assembly for a cathode of Si system is severe a change in volume and the surface side reactions there is let come out again during the discharge a large amount of lithium used in charge, to improve such an initial irreversible when there.Aye embodiment undergoes a side reaction generated when the first pre-charge. Therefore, when creating a silse cell assembly subjected to charging / discharging is to be the first cycle proceeds in a non-reversible reduction conditions as those which will be the initial irreversible decrease.
[46]
According to the present, as in the Figure 1 invention, the lithium metal-forming the inorganic compound layer on the surface of a graphite electrode comprising the initial irreversible large SiO or SiO and, lithium metal lithium metal parts of the inorganic compound layer is that the initial irreversible decrease It is used as before lithiated purpose, mineral that is to be left before and after lithiated is characterized in that to help improve the safety of a cathode.
[47]
In particular, conventional techniques for coating a mixture of inorganic materials in the molten lithium slurry for the negative electrode due to the high reactivity of the lithium metal, but its manufacturability process is to be the lithium metal of the coating deteriorate tricky, the present invention is a lithium metal after creating a ribbon inorganic composite, wherein the lithium-metal-made, because of the thin film by rolling, an inorganic composite ribbon bonding the thin film to the cathode, which is an advantage to minimize the amount of time that lithium is exposed to the air.
[48]
[49]
The first step of the present invention is to make a mixture added to the inorganic powder in the molten lithium. The melting temperature of this time, the lithium is 180 ℃ to 400 ℃, and more preferably from 190 ℃ to 250 ℃. If the melting point of lithium to lithium is higher than the highest limit described above is not desirable to have a so high reactivity, and when the melting temperature of the lithium is less than the lowest limit described above, the lithium is not liquefied.
[50]
According to an appropriate embodiment of the invention, the inorganic powder is alumina (Al 2 O 3 ), titanium dioxide (TiO 2 ), zirconium dioxide (ZrO 2 ), silicon dioxide (Si0 2 ), tin oxide (Sn0 2 ), oxide cerium (Ce0 2 ), magnesium oxide (MgO), calcium oxide (CaO) and yttria (Y oxide 2 O 3 may be alone or in combination of two or more selected from a). This is of alumina is most preferred. According to an appropriate embodiment of the invention, the particle size of the inorganic powder is 0.1 to 10㎛, and more preferably 0.3 to 5㎛, most preferably from 0.5 to 1㎛ decided. If the particle diameter of the inorganic powder exceeds 10㎛ is not preferable because it may not be well dispersed in the molten lithium.
[51]
[52]
According to the preferred embodiment of the present invention, the ratio of the inorganic powder to be added to the melted lithium, lithium 70 to 85% by volume, from 15 to 30% by volume of inorganic substance. When satisfied with the blending ratio, there is the effect to all lithiated and safety improvement in the negative electrode.
[53]
According to an appropriate embodiment of the present invention, by additionally added to the binder in addition to the inorganic powder in the molten lithium solution, a lithium metal - it is possible to prevent the inorganic compound layer is desorbed from the negative electrode. The binder I is typically bonded to be used as may be used, and PVDF, a SBR-based binder typically. Also it may be used PAA (Poly acrylic acid) series, CMC (Carboxymethyl cellulose) based, polyimide (Polyimide) binder.
[54]
Preferred content of the binder is added to the melted lithium, it is preferably added 1 to 10 parts by weight based on 100 parts by weight of the inorganic powder to be added together. 1, the lithium metal is less than parts by weight - if the concern is desorbed from the negative electrode layer and the inorganic compound, is more than 10 parts by weight is not preferable in all lithiated side.
[55]
[56]
A second step of the present invention, after extruding the mixture, and cooling the lithium metal-to manufacture an inorganic material composite ribbon. Method of extruding the mixture may be of a known method, and cooled to room temperature after extrusion of 100 ~ 200㎛ thick lithium metal-make inorganic composite ribbon. Lithium metal-inorganic material composite ribbon thickness can be adjusted depending on the purpose. The lithium-metal-case is less than the thickness of the inorganic composite ribbon 100㎛ the Li metal as extrusion - if there is a difficult to produce the inorganic composite ribbon problem, exceeding 200㎛ the Li metal produced by extrusion-thinning the inorganic composite ribbon there is a disadvantage that this process costs of energy and production time is increased during the rolling process to.
[57]
[58]
A third step of the present invention, the lithium metal-inorganic composite film to make a lithium metal by rolling the inorganic composite ribbon. The lithium-metal-rolling method for the inorganic composite ribbon may generally be in the method for rolling the metal in the form of a thin film.
[59]
According to an appropriate embodiment of the invention, the lithium metal after rolling - thickness of the inorganic compound thin-film is from 1 to 50㎛. More preferably 1 to 30㎛, most preferably 5 to 10㎛. Lithium metal-safety improvement around the lithiated and the battery when the thickness of the inorganic thin film composite 1 to 50㎛ an effect is exerted on.
[60]
[61]
Conventionally, lithium metals - because create binding them to the negative electrode to the inorganic composite film, - The application of the inorganic mixture slurry to the cathode that process, but righteousness particularity, the present invention provides a lithium metal in the second step and the step of the third stage relatively easily by the method of lithium metal on the negative electrode-will it has a feature of the present invention in a form having an inorganic compound layer.
[62]
[63]
A fourth step of the present invention, the lithium metal on the surface of the cathode - to form an inorganic compound layer, raised the inorganic composite film of lithium metal. That the lithium metal in the negative electrode - that is, move up to the inorganic composite film, lamination by bonding under heat and pressure to the contents.
[64]
[65]
According to an appropriate embodiment of the invention, the lithium metal-inorganic compound layer is not activated after the initial charge, the remaining lithium metal in the form.
[66]
[67]
On the other hand, the present invention has the characteristic that even in providing a secondary battery including the negative electrode produced in the same manner as described above.
[68]
A secondary battery according to the present invention is composed by two separate electrodes of different polarities are stacked in a separate state to the separator housing a formed electrode assembly, the electrode assembly is a cathode including a positive electrode, a negative electrode active material comprising a positive electrode active material , and it is composed of a separator.
[69]
[70]
Specifically, the positive electrode is, for example, be prepared by drying after applying the mixture of the positive electrode active material, conductive material and a binder on a positive electrode collector, as necessary, a filler may be further added to the mixture.
[71]
[72]
The positive electrode active material according to the present invention lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ) the compound substituted by a layered compound or one or more transition metals, and the like; Formula Li 1 + x Mn 2-x O 4 (where, x is from 0 to 0.33), LiMnO 3 , LiMn 2 O 3 , LiMnO 2 , such as lithium manganese oxide (LiMnO 2 ); lithium copper oxide (Li 2 CuO 2 ); LiV 3 O 8 , LiFe 3 O 4 , V 2 O 5 , Cu 2 V 2 O 7 of vanadium oxide and the like; Formula LiNi 1-x M x O 2 (where, M = Co, Mn, Al , Cu, Fe, Mg, B or Ga, and, x = 0.01 ~ 0.3 Im) Ni-site type lithium nickel oxide (lithiated nickel expressed in oxide); Formula LiMn 2-x M x O 2 (where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li 2 Mn 3 MO 8 (where, M = Fe, Co, Ni, lithium manganese composite oxides represented by Cu or Zn); LiMn lithium portion of the formula is substituted by an alkaline earth metal ion 2 O 4 ; disulfide compounds; Fe 2 (MoO 4 ) 3Or it may be mixed with the compound containing as a main component a lithium adsorbent material (lithiumintercalation material), such as composite oxides formed by combination thereof.
[73]
[74]
The cathode current collector is generally fabricated to have a thickness of 3 to 500 ㎛. The cathode current collector, if it has suitable conductivity without causing chemical changes in the fabricated battery is not particularly limited, for example, the surface of stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel on carbon, nickel, titanium and the like may be used as a surface treatment or the like. Current collector may increase the adhesive strength of the positive electrode active material to form fine irregularities on the surface thereof, films, sheets, foils, nets, porous structures, foams and non-woven fabrics and so on can take various forms.
[75]
[76]
The conductive material is commonly added in the mixture including the cathode active material to the total weight of 1 to 50% by weight. This conductive material so long as it has suitable conductivity without causing chemical changes in the fabricated battery is not particularly limited, for example, graphite such as natural graphite or artificial graphite; Carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, carbon black and thermal black; Conductive fibers such as carbon fibers and metallic fibers; Metal such as carbon fluoride, aluminum, nickel powder, powder; Conductive whiskers such as zinc oxide and potassium titanate; Conductive oxides such as titanium oxide; Poly is a conductive material such as phenylene derivative may be used.
[77]
[78]
The binder is a component assisting in binding to the total binding and the home, such as the active material and the conductive material is commonly added in the total mixture weight, includes the cathode active material of 1 to 50% by weight. Examples of the binder include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose by Woods (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinyl pyrrolidone, ethylene, polyethylene tetrafluoroethylene , polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene beuti butylene rubber, fluoro rubber and various copolymers and the like.
[79]
[80]
Up pingye polymer of the filler and so on it is optionally used as a component of suppressing the expansion of the positive electrode, if the standing fibrous materials without causing chemical changes in the fabricated battery, nor particularly limited, for example, polyethylene and polypropylene; And fibrous materials such as glass fiber and carbon fiber.
[81]
[82]
Further, the cathode is fabricated by applying and drying a negative electrode material on a negative electrode current collector and, if necessary, may be further included to the same components described above.
[83]
[84]
The anode current collector is generally fabricated to have a thickness of 3 to 500 ㎛. The anode current collector, so long as it has suitable conductivity without causing chemical changes in the fabricated battery is not particularly limited, for example, of copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel surface to be surface-treated with carbon, nickel, titanium or silver, and aluminum-cadmium alloys. Also Similar to the cathode current collector, to form fine irregularities on the surface may enhance the bonding strength between the negative electrode active material, films, sheets, foils, nets, porous structures, foams and non-woven fabrics or the like can be used in various forms.
[85]
Negative electrode active material of the present invention, it is possible to use a material which reversibly inserts / release lithium ions such as silicon (Si) or tin. With this material, it is that of the composite anode active material including the organization, an alloy, a compound, a solid solution and a silicon-containing material or a tin-containing material which would also exert the effects of the present invention are possible. A silicon containing material, Si, SiO x (0.5
[107]
After the molten lithium ingot prepared by the (molten) and sufficiently molten lithium at a temperature of 180 ° C or more also, the particle size of Al 0.5 ~ 1.0㎛ 2 O 3 and the mixture was stirred by introducing the powder was prepared. At this time, the molten lithium and Al 2 O 3 ratio is in a volume ratio of 75 vol.% Li, Al 2 O 3 was adjusted to 25% by volume. Producing a molten lithium - Al 2 O 3 and the mixture was extruded at a gap of 100㎛ mold, cooled to room temperature lithium metal having a thickness of 100㎛ - Al 2 O 3 was prepared in a ribbon. The lithium metal - Al 2 O 3 Al - Li metal ribbons by rolling in a thickness 5㎛ 2 O 3 thin film was prepared.
[108]
[109]

[110]
As the negative electrode active material by the addition of SiO 92% by weight of Denka black (Denka Black, a conductive agent) and 3% SBR (binder) 3.5% by weight, and CMC (thickener) 1.5% by weight in water to prepare a negative electrode mixture slurry.
[111]
On a surface of a copper collector, and coating the negative electrode mixture slurry, which was dried and rolled to prepare a negative electrode was punched into a predetermined size.
[112]
[113]

[114]
Lithium metal of the thickness of the finished 5㎛ the SiO negative electrode - Al 2 O 3 was formed on the surface of the composite thin film lamination method to prepare an electrode.
[115]
[116]

[117]
Relative (counter) was used as the lithium metal foil (150μm) to the electrode, as the anode and then through a polyolefin separator between the counter electrode, ethylene carbonate (EC), ethyl methyl carbonate in a volume ratio (DEC) 50:50 by injecting a 1M lithium phosphate hexafluoride (LiPF6) is dissolved in a mixed solvent of the electrolytic solution was prepared a coin-type half cell.
[118]
[119]
Example 2
[120]
Li metal - Al 2 O 3 the thickness of the ribbon 150㎛, lithium metal - Al 2 O 3 was prepared in a cell in the same manner as in Example 1 except for changing the thickness of the thin film to 5㎛.
[121]
[122]
Example 3
[123]
Li metal - Al 2 O 3 200㎛ the thickness of the ribbon, the lithium metal - Al 2 O 3 was prepared in a cell in the same manner as in Example 1 except for changing the thickness of the thin film to 10㎛.
[124]
[125]
Example 4
[126]
Al in the molten lithium 2 O 3 with a powder, SBR-based binder (Al 2 O 3 with respect to 100 parts by weight, 6 parts by weight) to prepare a cell in the same manner as in Example 1, except that the input point.
[127]
[128]
Example 5
[129]
Al in the molten lithium 2 O 3 with a powder, polyacrylic Acid (PAA) binder (Al 2 O 3 with respect to 100 parts by weight, 8 parts by weight), except that the input to the battery in the same manner as in Example 1 It was prepared.
[130]
[131]
Example 6
[132]
The molten lithium and Al 2 O 3 the ratio of the lithium 78 vol%, Al 2 O 3 , except that was adjusted to 22% by volume was prepared in a cell in the same manner as in Example 1.
[133]
[134]
Comparative Example 1
[135]
Cathode in the embodiment of the average thickness of lithium metal -Al 5㎛ of 1 2 O 3 was prepared in a cell in the same manner as in Example 1 except for using SiO electrode are not yet processed instead of SiO electrode composite layer is formed.
[136]
[137]
Comparative Example 2
[138]
Into the form of MgO powder to a molten lithium and mixed with it (by weight of lithium and MgO particles, 8: 2). In an argon protective gas atmosphere, and then the MgO is to transfer the molten lithium to mixing extrusion coater, the coating of Example 1 so that the thickness of the SiO negative electrode surface 5㎛ the mixed molten lithium, and then cooled at room temperature. After the battery was prepared in the same manner as in Example 1.
[139]
[140]
Comparative Example 3
[141]
Comparative Example 2 instead of MgO in Al 2 O 3 the cell in the same manner and is as in Comparative Example 2 except that a mixture of particles in the molten lithium was prepared.
[142]
[143]
Comparative Example 4
[144]
In Comparative Example 2 was prepared in a cell in the same manner and is as in Comparative Example 2 except that the coating thickness was adjusted to 10㎛.
[145]
[146]
Comparative Example 5
[147]
The point to adjust the coating thickness to 10㎛ in Comparative Example 3 was prepared, and the cells in the same manner as in Comparative Example 3, except.
[148]
[149]
Comparative Example 6
[150]
During coating in Comparative Example 2 was prepared in a cell in the same manner as the comparative example 2 except that did not form a protective argon gas atmosphere.
[151]
[152]
Comparative Example 7
[153]
During coating in Comparative Example 3 was prepared in a cell in the same manner as in Comparative Example 3 except that it did not form a protective argon gas atmosphere.
[154]
[155]
Experimental Example 1 The first cycle charge-discharge reversibility test
[156]
Examples and compared using a coin-type half-cell for electrochemical charge discharger prepared in Examples were tested for charge-discharge reversibility. The first cycle charging 0.005V (vs. Li / Li + voltage) voltage 0.1C-rate 1.5V (vs. Li / Li +) at a current density of charged and dropped by applying an electric current at a current density, during the discharge of up to It was carried out to discharge. At this time, the charge capacity and the discharge capacity was measured, by calculating the rate (discharge capacity / charge capacity of 100 *) are shown in Table 1 below.
[157]
[158]
Experimental Example 2. The calorimeter test
[159]
Calorimetry tests (differential scanning calorimetry) issued a scrape the Examples and Comparative Examples after the dolls nose half cell one cycle charge and discharge as described above, gave a cathode was activated by the charged up to 0.005V at the second cycle to. In this way the addition of the electrolyte solution in a charged cathode 0.1ml 13mg powder obtained was loaded into the DSC equipment (mettle Toledo). Thus heating the loaded sample at a heating rate of 10 ℃ / min, and by measuring the amount of heat The results are shown in Table 1.
[160]
[161]
TABLE 1
The first charge-and-discharge efficiency (%) Onset(℃) Main peak(℃) Heating value (J / g)
Example 1 95 120 296 2023
Example 2 93 120 297 2027
Example 3 92 120 296 2022
Example 4 91 121 298 2033
Example 5 90 122 298 2030
Example 6 94 120 296 2019
Comparative Example 1 73 97 261 4150
Comparative Example 2 85 115 271 2950
Comparative Example 3 87 120 280 2680
Comparative Example 4 87 116 270 2900
Comparative Example 5 88 120 280 2580
Comparative Example 6 78 115 270 3380
Comparative Example 7 79 120 280 3155

[162]
[163]
Embodiment the first cycle charge-discharge reversibility of 1 was improved by 22% than Comparative Example B. This embodiment the reason reversible improvement in one of lithium metal was formed on the SiO electrode surface-aroused a pre-surface side reactions, the lithium metal of the inorganic composite layer reacts with SiO, volume expansion by the previously gyeongham the volume change that occurs during charging Dead- lithium by also determined by since jwotgi made in advance. To undergo such side reactions by the pre it was able to reduce the lithium consumed by side reactions during the actual first charge, so that it is considered that when a lithium metal containing charge almost come to the most reversible.
[164]
[165]
In the case of Examples 1-6 than in Comparative Example 1 was shown that higher the onset temperature, the main peak temperature, which is interpreted to mean that the cells are more securely held to the high temperature. In addition, it is also the amount of heat generated in Examples 1 to 6 is less than that of the comparative example 1 are interpreted to mean that the more secure during high temperature exposure. This embodiment of the lithium metal-reason inorganic composite layer is shown for a safer result introduced SiO electrode is lithium metal-back the lithium metal in the inorganic compound layer disappeared after around lithiated, the remaining inorganic layer to the remainder of SiO electrode surface It is determined to have a role as a protective layer for protecting.
[166]
[167]
Cells of Comparative Examples 2 to 7, the lithium metal in the negative electrode - can be observed that the mineral compound layer is a charge-discharge efficiency, poor as compared with, exemplary cell of Example 1-6 was introduced. This molten lithium is thought to be because in the process of applying the inorganic material mixture solution to SiO negative electrode, the result is a lithium metal is exposed to the atmosphere, the deterioration of lithium was not sufficient before the lithium of the negative electrode upset.
[168]
[169]
Reference Numerals
[170]
10: molten lithium
[171]
20: inorganic fire powder
[172]
30: Extruder
[173]
40: lithium-metal-inorganic material composite ribbon
[174]
50: rollers
[175]
60: lithium-metal-composite film
[176]
70: negative
[177]
80: inorganic layer
[178]
90: All the lithiated cathode

Claims

[Claim 1]The first step to make a mixture added to the inorganic powder in the molten lithium; After extruding the mixture, and cooling the lithium metal in 100 ~ 200㎛ thickness - a second step of preparing an inorganic composite ribbon; A third step of preparing an inorganic composite film-lithium metal by rolling the inorganic composite ribbon, wherein the lithium metal; And the lithium metal on the surface of the cathode - a fourth step of forming an inorganic compound layer, raised the inorganic composite film of lithium metal; I lithiated method of a negative electrode comprising a.
[Claim 2]
According to claim 1, wherein said lithium-metal-I lithiated method of the secondary battery, the negative electrode, characterized in that the thickness of the inorganic composite film is from 1 to 50㎛.
[Claim 3]
The method of claim 1, wherein the inorganic powder is alumina (Al 2 O 3 ), titanium dioxide (TiO 2 ), zirconium dioxide (ZrO 2 ), silicon dioxide (Si0 2 ), tin oxide (Sn0 2 ), cerium oxide (Ce0 2 ), magnesium (MgO), calcium oxide (CaO) and yttria (Y oxide 2 O 3 ) around the lithiated cathode of a secondary battery of one kind or not less than two kinds selected from a method.
[Claim 4]
The method of claim 1, wherein the mixing ratio of the molten lithium, and inorganic powders of the negative electrode lithiated before, characterized in that 70 to 85% by volume of lithium, inorganic material of 15 to 30% by volume method.
[Claim 5]
The method of claim 1 wherein before the method of lithiated cathode comprising a step of mixing an additional binder in addition to the inorganic powder in the molten lithium solution.
[Claim 6]
According to claim 1, wherein said lithium-metal-inorganic material composite layer around the lithiated method of the secondary battery, the negative electrode, characterized in that the initial activation since there are not left in the lithium form of the metal charge.
[Claim 7]
The method of claim 1, wherein the particle size of the inorganic powder before lithiated method of the secondary battery, the negative electrode, characterized in that 0.1 to 10㎛.
[Claim 8]
According to claim 1, wherein said cathode is lithiated former method of a secondary battery negative electrode comprising a silicon oxide.
[Claim 9]
The negative electrode of a secondary battery manufactured by applying the pre lithiated method according to one of the preceding claims.
[Claim 10]
A secondary battery comprising the negative electrode according to claim 9.