RU2484556C2 - Electrolyte for chemical current source - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: electrolyte contains potassium chloride and lithium choride, metavanadate and molybdate at the following components ratio, wt %: potassium chloride 39.62…42.70; lithium chloride 30.79…33.08; lithium metavanadate 8.34…9.26; lithium molybdate 15.89…20.32.

EFFECT: reduced specific enthalpy and melt temperature.

1 tbl, 3 ex

Description

The invention relates to the field of the electrical industry, in particular to the development of molten electrolytes of high-temperature thermal chemical current sources, including lithium and potassium chlorides and other lithium salts.

Known compositions that can be used as electrolytes for chemical current sources, namely:

1) containing vanadate and lithium molybdate; the melting temperature of the mixture is 533 ° C, the specific enthalpy of melting is 328 J / g (Belyaev I.N., Lupeyko T.G., Vyalikova V.I. LiVO ₃ -Li ₂ Mo (W) O ₄ and NaVO ₃ -Na ₂ systems Cr (Mo) O ₄ // Journal of Inorgan, Chemistry. 1975. Vol. 20. No. 9. P.2483-2486);

2) containing lithium chloride and molybdate; the melting temperature of the mixture is 501 ° C, the specific enthalpy of melting is 302 J / g (Trunin A.S. Study of ternary reciprocal systems Li, Ва || Cl, MoO ₄ and Li, Ва || Cl, WO ₄ // Bulletin of the North Caucasus Center for Higher Education Natural Sciences. 1980. No. 3. S. 53-55).

The disadvantage of these compositions is the relatively high enthalpy and melting point.

Closest to the claimed composition in temperature and components is the low-melting composition of the LiCl-KCl system (Chemical current sources / edited by N.V. Korovin: MEI Publishing House, 2003, 740 s). The melting point of the eutectic composition is 358 ° C. The disadvantage of this composition is also the high melting point of the mixture.

The technical result of the invention is the possibility of using the composition as an electrolyte for a chemical current source in the temperature range 336-341 ° C. The technical result is achieved in that the electrolyte contains potassium chloride, chloride, metavanadate and lithium molybdate in the following ratio of components, wt.%:

potassium chloride 39.62 ... 42.70

lithium chloride 30.79 ... 33.08

lithium metavanadate 8.34 ... 9.26

lithium molybdate 15.89 ... 20.32

The novelty of the claimed composition compared to the known one lies in the fact that this composition contains lithium and potassium chlorides and other lithium salts, where lithium salts are taken metavanadate and lithium molybdate, which allows to reduce the melting temperature and reduce energy consumption for its melting.

Examples of specific performance.

Example 1

In a shaft-type electric furnace, anhydrous salts of the qualification “hch” (LiCl, LiVO ₃ ) and “chda” (Li ₂ MoO ₄ , KCl) 0.4270 g (42.70 wt.%) Potassium chloride +0.3308 g (33.08 wt.%) Are melted lithium chloride +0.0834 g (8.34 wt.%) lithium metavanadate +0.1589 g (15.89 wt.%) lithium molybdate.

The melting point of the mixture is 338 ° C.

The specific melting enthalpy was calculated by the formula:

$${\text{Δ}}_{\text{m}}{\text{H}}_{\text{E}}={\text{Δ}}_{\text{t}}{\text{H}}_{\text{floor}}\frac{{\text{S}}_{\text{E}}}{{\text{S}}_{\text{floor}}}\cdot \frac{{\text{T}}_{\text{E}}}{{\text{T}}_{\text{floor}}}\text{J / g}\text{,}$$

where Δ _t H _E is the specific enthalpy of the phase transition of a substance close in phase transition temperature to the composition under study, J / g; S _E , S _et - peak areas of the differential curves corresponding to the melting of the eutectic composition and phase transition of the reference substance, respectively; T _e , T _et are the melting points of the eutectic composition and phase transition of the reference substance, respectively, K. The final enthalpy was found as the average of three measurements. KNO ₃ (melting point 338 ° C, specific enthalpy of melting 115.8 J / g) was taken as a reference substance.

The specific enthalpy of the composition is 291 kJ / kg.

Example 2

In a shaft-type electric furnace, anhydrous salts of the qualification “hch” (LiCl, LiVO ₃ ) and “chda” (Li ₂ MoO ₄ , KCl) are smelted 0.3962 g (39.62 wt.%) Potassium chloride +0.3079 g (30.79 wt.%) Lithium chloride +0.0926 g (9.26 wt.%) Lithium metavanadate +0.2032 g (20.32 wt.%) Lithium molybdate.

The melting point of the mixture is 341 ° C.

Specific enthalpy of melting 298 kJ / kg.

Example 3

In a shaft-type electric furnace, anhydrous salts of the qualification “hch” (LiCl, LiVO ₃ ) and “chda” (Li ₂ MoO ₄ , KCl) 0.4133 g (41.33 wt.%) Potassium chloride +0.3173 g (31.73 wt.%) Lithium chloride are remelted +0.0881 g (8.81 wt.%) Lithium metavanadate +0.1813 g (18.13 wt.%) Lithium molybdate.

The melting point of the mixture is 336 ° C.

Specific melting enthalpy of 295 kJ / kg.

Beyond the claimed limits, the single-phase composition is violated, the temperature rises, which leads to an increase in energy consumption for melting the mixture.

The table shows the comparative characteristics of the properties of the claimed composition and composition, selected as a prototype.

Compositions The composition of the mixture, wt.% Specific enthalpy of melting, kJ / kg Melting point, ° C Kcl LiCl LiVO ₃ Li ₂ MoO ₄ Prototype 52.4 47.6 - - - 358 Proposed one 42.70 08/33 8.34 15.89 291 338 2 39.62 30.79 9.26 20.32 298 341 3 41.33 31.73 8.81 18.13 295 336

As can be seen from the table, the proposed composition has a temperature of 17-22 ° C lower compared to the prototype, which significantly reduces the energy consumption for melting the composition and bringing it into working condition, and also extends the range of use in temperature.

Claims (1)

An electrolyte for a chemical current source, including lithium, potassium chlorides and other lithium salts, characterized in that its metavanadate and molybdate are introduced as lithium salts in the following ratio, wt.%:
potassium chloride 39.62-42.70 lithium chloride 30.79-33.08 lithium metavanadate 8.34-9.26 lithium molybdate 15.89-20.32