RU2553999C1 - Composition of liquid-crystalline ionic electrolyte - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: composition of electrolyte includes salt of electrolyte and a solvent, where lithium salt of dodecylbenzene sulphonic acid is contained as salt of electrolyte in the amount of 25-55 wt % and water 75-45 wt % is contained as a solvent, or sodium salt of dodecylbenzene sulphonic acid in the amount of 70-88 wt % and water 30-12 wt %. Use of affordable anionic surface-active substances makes the proposed ionic liquid-crystalline electrolytes economically attractive.

EFFECT: obtaining an electrolyte with high specific conductivity at availability of a well-ordered inner structure and preservation of flowability.

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Description

The invention relates to the field of electrical industry, in particular to the development of electrolytes for chemical current sources. Promising ion conductive electrolytes are ionic liquid crystals. In particular, ionic lyotropic liquid crystals based on salts of dodecylbenzenesulfonic acid. Lyotropic ionic liquid crystals based on salts of dodecylbenzenesulfonic acid possess such advantages as low toxicity, thermodynamic stability of the liquid crystalline phase over a wide temperature range, high specific conductivity in sodium and lithium, which, combined with a self-organizing ordered nanostructure, makes them attractive for widespread use.

A large number of different electrolytes have been developed and patented, including electrolytes based on liquid crystals of various nature, that is, lyotropic, thermotropic and polymerizable liquid crystals. Various solid electrolytes, polymer and crystalline, solutions of various lithium and sodium salts in a number of organic solvents, for example, ethylene carbonate, and liquid crystal ionic conductors have been proposed and patented as ionic conductors.

We propose to use lyotropic liquid crystals in the water – dodecylbenzenesulfonate Li / Na system as the basis for ionic conductors. The use of affordable anionic surfactants to produce liquid crystals makes the electrolytes of the invention economically attractive.

A number of liquid crystalline ionic conductors are known, obtained by mixing a molten organic salt (ionic liquid) with organic or inorganic substances capable of forming a liquid crystalline phase, as described in EP 1394816 A1 by Kato Takashi, Kanie Satoshi, Yoshio Masafumi, Ohno Hiroyuki, Yoshizawa Masoi ion conductor and method for preparation thereof ”dated 03.03.2004 (IPC H01B 1/06). The patent describes various electrolyte compositions in which it is possible to form a liquid crystal ionic conductor based on ionic liquids and various liquid crystal molecules.

The known electrolyte composition based on a polymerizable ionic liquid crystal for electrochemical current sources in European patent EP 116769 B1 Ono Michio "Electrolyte composition, electrochemical cell and ionic liquid crystal monomer" from 01/18/2001 (IPC H01G 9/20, C09K 19/00, C09K 19/38). The composition of the claimed electrolyte includes polymerizable liquid crystal monomers containing at least one polymerizable group, also the ionic liquid crystal monomer has an organic cation-containing and ethylene oxide groups.

The patent WO 2006/062014 A1 Haramoto Yuiciro "Conductive liquid-crystal material, process for producing the same, liquid-crystal composition, liquid-crystal semiconductor element, and information memory medium" dated 06.15.2006 (IPC G09K 19 / 16, H01L 51/50, G02F 1/13). The invention describes a liquid crystal composition, which even at room temperature has excellent conductivity, with a 5V electrochemical voltage window. The composition consists of one or more components that form the smectic liquid crystal phase.

The closest in technical essence (prototype) to the claimed invention is an electrolyte composition containing at least one electrolyte salt and a mixture of organic solvents, ethylene carbonate 10-50% and fluoroethylene carbonate 50-90%. (Patent WO 2013/033579 A1 Chen Xudong, Holstein William L. “Fluorinated electrolyte compositions” dated 07.03.2013, IPC H01M 10/0525, H01M 10/0569, H01M 10/0567).

The composition claimed in this patent contains a Na / Li salt of dodecylbenzenesulfonic acid and water as a solvent, in certain proportions, which make it possible to obtain an ordered nanostructured liquid crystal phase.

The technical result of the invention is the high conductivity of the resulting electrolyte in the presence of an ordered internal structure and maintaining fluidity, which distinguishes these electrolytes from the prototype.

The technical result is achieved by a composition containing lithium salt of dodecylbenzenesulfonic acid in an amount of 25-55% (wt.) And 75-45% (wt.) Of water or containing sodium salt of dodecylbenzenesulfonic acid in an amount of 70-88% (wt.) And 30-12 % (wt.) water.

Obtaining liquid crystals in the salt system of dodecylbenzenesulfonic acid - water includes the following operations:

- obtaining the sodium / lithium salt of dodecylbenzenesulfonic acid;

- obtaining a solution of the required concentration.

Example 1

In 1x we add 1 g of dodecylbenzenesulfonic acid. Next, add with stirring an aqueous solution of lithium hydroxide to a neutral pH of 7. In the future, after neutralizing the acid, evaporate the resulting mixture to the desired concentration.

The presence or absence of a liquid crystal structure and its type were determined by polarization microscopy using an Axiostar plus microscope for observation in transmitted light (Zeiss, Germany) with a Canon digital camera.

Figure 1 is an example of a micrograph through crossed polaroids (left) and transmitted light (right) of lyotropic liquid crystals of hexagonal structure obtained in the lithium dodecylbenzenesulfonate-water system. The sample contains 51% (wt.) Lithium dodecylbenzenesulfonate and 49% (wt.) Water. The micrograph shows the texture of the sample, characteristic of liquid crystals of a hexagonal structure.

Example 2

The preparation of liquid crystals was carried out according to the procedure described in example 1. The presence of a liquid crystal structure was checked by polarization microscopy, as described in example 1. Table 1 shows the composition of the samples obtained in the lithium dodecylbenzenesulfonate-water system at 25 ° C and the presence of them liquid crystal structure. As can be seen from the data presented, the ranges of the components indicated in the claims correspond to the region of existence of liquid crystals in the lithium dodecylbenzenesulfonate-water system.

Table 1 The composition, structure and conductivity of the samples obtained in the lithium dodecylbenzenesulfonate - water system at 25 ° C. Sample No. The content of components,% (wt.) Conductivity, mS / cm Structure Lithium dodecylbenzenesulfonate Water one twenty 80 2,3 L1 2 33 67 33.7 H1 3 38 62 32.9 H1 four 41 59 39.1 H1

5 51 49 19.2 H1 6 70 thirty 6.6 Lα 7 78 28 2.0 Lα 8 90 10 0.3 Lα * L1 - micellar isotropic phase ** H1 - hexagonal liquid crystal phase *** Lα - lamellar liquid crystal phase

Example 3

By the method described in example 1, with the replacement of sodium hydroxide, we obtain liquid crystals based on sodium dodecylbenzenesulfonate.

The presence or absence of a liquid crystal structure is confirmed as described in example 1.

Figure 2 is an example of a micrograph through crossed polaroids of lyotropic liquid crystals of lamellar structure, obtained in the system of sodium dodecylbenzenesulfonate - water. The sample contains 78% (wt.) Sodium dodecylbenzenesulfonate and 22% (wt.) Water. The micrograph shows the texture of the sample, characteristic of liquid crystals of the lamellar structure.

Example 4

The preparation of liquid crystals was carried out according to the procedure described in example 1. The presence of a liquid crystal structure was checked by polarization microscopy as described in example 1. Table 2 shows data on the composition of the samples obtained in the sodium dodecylbenzenesulfonate-water system at 25 ° C and the presence of them liquid crystal structure. As can be seen from the data presented, the ranges of the components indicated in the claims correspond to the region of existence of liquid crystals in the lithium dodecylbenzenesulfonate-water system.

table 2 The composition, structure and conductivity of the samples obtained in the sodium dodecylbenzenesulfonate - water system at 25 ° C. Sample No. The content of components,% (wt.) Conductivity, mS / cm Structure Sodium dodecylbenzenesulfonate Water one thirty 70 36.8 L1 + Lα 2 64 36 18.0 L1 + Lα 3 78 22 1.7 Lα four 90 10 0.11 Lα + HC * NS - crystalline phase

Claims (1)

The electrolyte composition, comprising at least one electrolyte salt and a solvent, characterized in that the electrolyte salt contains lithium salt of dodecylbenzenesulfonic acid in an amount of 25-55% (wt.) And the solvent contains water 75-45% (wt.) or the sodium salt of dodecylbenzenesulfonic acid in an amount of 70-88% (wt.) and water 30-12% (wt.).

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