JPH0351062B2 - - Google Patents

Description

[Detailed description of the invention]

(b) Industrial application field The present invention consists of a negative electrode using a light metal such as lithium or sodium as an active material, a positive electrode using a metal oxide, sulfide, or halide as an active material, and a solute and a solvent. The present invention relates to a non-aqueous electrolyte battery equipped with a non-aqueous electrolyte, and particularly relates to improvements in the non-aqueous electrolyte. (b) Prior art The nonaqueous electrolyte of this type of battery contains lithium perchlorate (LiClO ₄ ), lithium chloride (LiCl), lithium borofluoride (LiBF ₄ ), and lithium trifluoromethanesulfonate (LiCF ₃ SO _{3 )} as solutes. )
As the solvent, propylene carbonate, γ-butyrolactone, 1,2 dimethoxyethane, tetrahydrofuran, etc. are used alone or in combination of two or more. Now, in recent years, as the fields of application of this type of battery have expanded, improvements in battery characteristics have been desired. One of these is the desire to improve high-rate discharge characteristics after high-temperature storage. By the way, among solutes, lithium perchlorate, lithium borofluoride, lithium trifluoromethanesulfonate, etc. have high conductivity and are suitable for high-rate discharge, but they have problems with high-temperature storage characteristics.
Furthermore, although lithium decachlorodecaborate (Li ₂ B ₁₀ Cl ₁₀ ) is suitable for high-temperature storage characteristics, it has a problem in high-rate discharge due to its low conductivity. Therefore, in order to improve the high-temperature storage characteristics and high-rate discharge characteristics, it is conceivable to use a mixed solute rather than a single solute. On the other hand, as for the solvent, propylene carbonate is generally used, but its high viscosity makes it disadvantageous for high-rate discharge, and therefore the combination with a low-viscosity solvent is also being considered. Another point that needs to be taken into consideration is that the evaporation and loss of the solvent at high temperatures must be suppressed. As described above, various solutes and solvents have individual characteristics, so in order to satisfy both high-temperature storage characteristics and high-rate discharge characteristics, consideration must be given to selecting an appropriate combination of solutes and solvents. (c) Object of the Invention The object of the present invention is to improve a non-aqueous electrolyte and provide a non-aqueous electrolyte battery with excellent high-temperature storage characteristics and high-rate discharge characteristics. (d) Structure of the Invention The present invention has been made to achieve the above object, and includes a negative electrode whose active material is a light metal such as lithium or sodium or an alloy thereof, a solid positive electrode active material, and a solute. a nonaqueous electrolyte consisting of a solvent, the solute is a mixed solute containing at least lithium decachlorodecaborate, and lithium borofluoride or lithium trifluoromethanesulfonate, and the solvent is a non-aqueous electrolyte consisting of lithium decachlorodecaborate; The present invention proposes a non-aqueous electrolyte battery characterized by using a single solvent or a mixed solvent containing the same to form a complex with. As a result, the solvent does not vaporize even at its own boiling point temperature, and can contribute to improving high-temperature storage characteristics. (e) Examples Examples of the present invention will be described in detail below. A lithium rolled plate punched to a specified size was used as the negative electrode, and a mixture of manganese dioxide (active material), carbon powder (conductive agent), and fluorine resin powder (binder) was used as the positive electrode in a ratio of 85:10. After mixing at a weight ratio of 5:5, this mixture was pressure molded and heat treated. Then, button type batteries were prepared using various combinations of electrolytes as shown in the table below.
In addition, the solvent is propylene carbonate (PC) and 1,
An equal volume mixed solvent with 2 dimethoxyethane (DME) was used.

【table】

[Table] Figures 1 and 2 compare the characteristics of the batteries in the table above. Figure 1 shows the high rate discharge characteristics when discharging with a constant resistance of 500Ω at 25°C, and Figure 2 shows the high rate discharge characteristics at 60°C. After storage for 3 months, the high rate discharge characteristics are shown when discharged at a constant resistance of 500Ω at 25°C. Moreover, FIGS. 3 to 4 are diagrams showing the relationship between the concentration of each mixed solute and the discharge capacity, and in each case, the solvent is a mixed solvent of equal volumes of propylene carbonate and 1,2 dimethoxyethane. In addition, the maximum concentration of lithium decachlorodecaborate (Li ₂ B ₁₀ Cl ₁₀ ) was set at 0.15 mol/ because when lithium decachlorodecaborate is mixed with other solutes, the dissolved amount This is because the amount is about 0.2 mol/at most and no more is dissolved. (F) Effects of the Invention As described above, the present invention provides a negative electrode comprising a light metal such as lithium or sodium or an alloy thereof as an active material, a solid positive electrode active material, and a non-aqueous material comprising a solute and a solvent. a non-aqueous electrolyte battery comprising an electrolyte, wherein the solute is a mixed solute containing at least lithium decachlorodecaborate and lithium borofluoride or lithium trifluoromethanesulfonate; Since the solvent is a single solvent that forms a complex with chlorodecaborate or a mixed solvent containing the same, evaporation and loss of the solvent can be suppressed, and this type of battery can be provided with excellent high-temperature storage characteristics and high-rate discharge characteristics. In addition, although 1, 2 dimethoxyethane was illustrated as a solvent that forms a complex with lithium decachlorodecaborate, other examples include tetrahydrofuran, dioxolane, and the like.

[Brief explanation of drawings]

1 and 2 are battery characteristic diagrams, with FIG. 1 showing high rate discharge characteristics and FIG. 2 showing high rate discharge characteristics after high temperature storage. Further, FIGS. 3 to 4 are diagrams showing the relationship between the concentration of mixed solute and discharge capacity. A, B...Battery of the present invention, X, Y, Z...Comparative battery.

Claims (1)

[Claims] 1. A negative electrode comprising a light metal such as lithium or sodium or an alloy thereof as an active material, a solid positive electrode active material, and a non-aqueous electrolyte comprising a solute and a solvent, wherein the solute is is a mixed solute containing at least lithium decachlorodecaborate and lithium borofluoride or lithium trifluoromethanesulfonate, and the solvent is a single solvent that forms a complex with lithium decachlorodecaborate or a mixed solvent containing the same. A non-aqueous electrolyte battery characterized by: