JPS6224907B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to primary and secondary batteries that are small in size and have a large discharge capacity, and more particularly to a room-temperature operating battery that uses lithium as a negative electrode active material. Many proposals have been made for high energy density batteries that use lithium as a negative electrode active material. For example, halogens such as Br ₂ and I ₂ , CuF ₂ , AgF ₂ , AgF, NiF ₂ , etc. have been used as positive electrode active materials.
_CuCl2 , AgCl, _NiCl2 , _CoF3 , _CrF3 , _MnF3 ,
SbF ₃ , CdF ₂ , AsF ₃ , HgF ₂ , CuBr, CdCl ₂ ,
metal halides, such as _PbCl2 and _CoCl2 , etc.
Metal rhodanides such as AgSCN, CuSCN _{and Ni} (SCN) ₂ , _MnO2 , _Cr2O3 , _V2O5 , _SnO2 ,
_{PbO2 , TiO2} , _Bi2O3 , _CrO3 , _Fe3O4 , _NiO ,
Metal oxides like AgO, HgO, _Cu2O , CuO, _{Ag2WO4 etc.} , NiSx _, AgBS, CuBS, _{Pb2B2S5 and}
Metal sulfides such _{as MnB4S4} , layered compounds such as _TiS2 , _NbSe2 and _WS2 , graphite fluoride, and even organic compounds such as benzoquinones, dinitrobenzene, and _POCl3 , _SOCl2 and SO. Batteries using oxyhalides such as ₂ Cl ₂ have been proposed.
Specifically, for example, batteries are known that use graphite and fluorine intercalation compounds as positive electrode active materials, and lithium metal as negative electrode active materials (see US Pat. No. 3,514,337). In addition, lithium batteries using graphite fluoride as a positive electrode active material and lithium batteries using manganese dioxide as a positive electrode active material are already commercially available. However, in these batteries, for example, batteries using manganese dioxide, the specific capacity per positive electrode active material is approximately
Its characteristics were not necessarily sufficient to provide a compact, large-capacity battery as small as 310Ah/Kg. The present invention has been made in view of the current situation, and an object thereof is to provide a battery that is small in size and has a large capacity. To summarize the present invention, the normal temperature operating battery of the present invention has a positive electrode active material of manganese disulfide (MnS ₂ ),
A manganese compound selected from the group consisting of manganese diselenide (MnSe ₂ ) and manganese ditelluride (MnTe ₂ ), the negative electrode active material is lithium,
The electrolyte material is characterized in that it is chemically stable with respect to the positive electrode active material and lithium, and is a material that allows lithium ions to migrate to perform an electrochemical reaction with the positive electrode active material. When the above-mentioned manganese compound as a positive electrode active material in the present invention is used as a positive electrode, the positive electrode is formed by pressure-molding a powder of these manganese compounds or a mixture of this and a binder powder onto a support such as nickel or copper to form a film. or by mixing carbon powder to impart conductivity to these manganese compound powders,
It is formed by placing this mixture in a metal container, or by mixing the mixture with a binder solution, coating it on a support such as nickel or copper, drying it, and forming it into a film. Lithium, which is the negative electrode active material, is produced in the form of a sheet, similar to that of general lithium batteries.
Alternatively, the sheet may be pressed onto a nickel or copper mesh to form a negative electrode. As the electrolyte, aprotic organic solvents such as propylene carbonate, ethylene carbonate, γ-butyrolactone, dimethyl sulfoxide, acetonitrile, formamide, dimethylformamide, nitromethane, and LiClO ₄ , LiAlCl ₄ ,
Combination with lithium salts such as LiBF ₄ , LiCl or Li ⁺
Known electrolytes that are generally used in batteries that use lithium as a negative electrode active material can be used, such as a solid electrolyte that operates at room temperature and uses lithium as a conductor. Further, if necessary due to the battery structure, a diaphragm made of porous polypropylene or the like may be used. Next, the present invention will be explained with reference to Examples, but the present invention is not limited to these in any way. In addition, in the examples, battery fabrication was performed under a dry argon gas atmosphere. The theoretical capacities of MnSe ₂ , MnTe ₂ and MnS ₂ can be calculated as shown in Table 1, assuming that 4 mol of Li reacts with 1 mol of each manganese compound.

[Table] However, the values in Table 1 are only expected values, and do not necessarily match the experimental values as described in the Examples. This is because, for example, the theoretical energy density is determined assuming that the reaction with MnS ₂ is based on equation (1). MnS ₂ +4Li→Mn+2Li ₂ S (1) However, the reaction in the room-temperature operating type of the _present invention is a so-called intercalation reaction ( In short, it is caused by a reaction in which Li is trapped in the gaps between crystals. The reaction in this case can be written as equation (2). MnS ₂ +xLi→LixMnS ₂ (2) (However, at the positive electrode, MnS ₂ +xLi ⁺ +xe ^- →LixMnS ₂ ) When the reaction of formula (2) occurs, the covalent bond between Mn and S is broken. It can be fully predicted that charging will be possible because Li reacts without any problems. Example 1 FIG. 1 is a schematic cross-sectional view showing the configuration of a button-type battery that is a specific example of the present invention, in which 1 is a stainless steel container, 2 is a lithium negative electrode, 3 is a porous polypropylene diaphragm, and 4 is a diaphragm made of porous polypropylene. 5 indicates a felt made of carbon fiber, 5 indicates a positive electrode mixture, and 6 indicates a nylon packing. A battery was manufactured using the battery configuration shown in the drawings. The diameter of the battery cell was 20 mm and the height was 4 mm. As the electrolytic solution, 1 mol/solution of dehydrated LiClO ₄ dissolved in distilled dehydrated propylene carbonate was used, and the diaphragm 3 and the felt 4 made of carbon fiber were impregnated with the solution. Positive electrode mixture 5 is 0.03
g of MnSe ₂ powder and 0.06 g of acetylene black were mixed with the above electrolyte. A lithium sheet was used as the lithium negative electrode 2 with a porous polypyrene membrane 3 in between. The open circuit voltage of the battery made in this way is
It was 2.95V. The results of constant current discharge at 0.32 mA/cm ² are shown in FIG. 2A regarding the relationship between battery discharge time and voltage. The average electromotive force until the voltage reaches 1V is 1.81V, and the discharge capacity is 507Ah/
Kg, and the energy density was 919Wh/Kg. The discharge capacity almost matched the theoretical capacity shown in Table 1. Next, FIG. 3 shows the results of the charging and discharging characteristics of this battery. Figure 3 shows 1 after discharging at 0.32mA/ ^cm2 for 10 hours.
1 after resting for 10 hours and charging at 0.32mA/ ^cm2 for 10 hours.
This shows the results of repeating the process of stopping for a period of time and then starting the discharge again up to the fifth time.
It can be seen that MnSe ₂ is a chargeable positive electrode active material. Example 2 As positive electrode mixture 5, 0.03 g of MnTe ₂ powder and 0.06
The battery shown in FIG. 1 was fabricated in the same manner as in Example 1, except that the acetylene black (g) was mixed and formed with the same electrolyte as in Example 1. The open circuit voltage of the battery made in this way is
It was 3.08V. The results of constant current discharge at 0.32 mA/cm ² are shown in Figure 2B. The average electromotive force until the voltage reaches 1V is 1.64V, and the discharge capacity is also
467Ah/Kg, energy density 767Wh/Kg,
It was possible to charge like MnSe ₂ . The discharge capacity is 135% of the theoretical capacity shown in Table 1, and MnTe ₂ 1
It can be seen that 5.4 moles of Li react per mole. Example 3 0.03g of MnS ₂ powder and 0.06g as positive electrode mixture 5
The battery shown in FIG. 1 was prepared in the same manner as in Example 1, except that the acetylene black was mixed with the same electrolyte as in Example 1. The open circuit voltage of the battery made in this way is
It was 3.10V. The results of constant current discharge at 0.32 mA/cm ² are shown in Figure 2C. The average electromotive force until the voltage reaches 1V is 1.66V, and the discharge capacity is also
383Ah/Kg, energy density 636Wh/Kg,
It was possible to charge like MnSe ₂ . The discharge capacity was 43% of the theoretical capacity shown in Table 1, indicating that 1.7 mol of Li reacted per 1 mol of MnS ₂ . Currently, the positive electrode active material widely used in lithium primary batteries is MnO ₂ , and its discharge capacity is approximately 310Ah/Kg. As is clear from the above explanation, the battery of the present invention has a capacity of 507Ah/Kg for MnSe ₂ and 507Ah/Kg for MnTe ₂ .
It has a discharge capacity of 467Ah/Kg and 383Ah/Kg for MnS ₂ , which is greater than conventional batteries using MnO ₂ or the like as the positive electrode active material, and it has the advantage of being able to be used in various fields as a small, large-capacity battery. Also, as a secondary battery, for example, when MnSe ₂ is used, it has a large capacity of 333 Ah/Kg, and has the advantage of being usable in various fields as a small, large-capacity secondary battery.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing the structure of a button-type battery that is a specific example of the present invention, FIG. 2 is a graph showing the relationship between battery discharge time and voltage in each embodiment of the present invention, and FIG. Figure 3 shows the charge-discharge cycle characteristics of a battery using MnSe ₂ as the positive electrode active material. 1... Stainless steel container, 2... Lithium negative electrode, 3... Porous polypropylene diaphragm, 4...
Felt made of carbon fiber, 5... Positive electrode mixture, 6... Nylon packing.

Claims (1)

[Claims] 1 The positive electrode active material is a manganese compound selected from the group consisting of manganese disulfide, manganese diselenide, and manganese ditelluride, the negative electrode active material is lithium, and the electrolyte material is a chemical compound with respect to the positive electrode active material and lithium. 1. A room-temperature operating battery characterized by being a substance that is stable and allows lithium ions to move to undergo an electrochemical reaction with a positive electrode active material.