PREPARATI ON OF I ONI C FLUI D ELECTROLYTES COMPRI SI NG TRANSI Tl ON M ETAL- NI TRATE SALTS Technical Field of The I nvent ion

The invention is related to the preparation of ionic fluids comprising zinc and alum inium nitrate. Said ionic fluids are usable as electrolyte and may be implemented to the present battery technology and super capacitors.

Background of The I nvent ion ( Prior Art)

The medium where the energy storage of battery and super capacitor technologies are made contains water or organic solvent ; or ionic fluid. I onic fluids, which have larger potential compared to organic solvents, increase energy density in battery and the super capacitor. I onic fluids have an opportunity to be used especially in Dye-Sensitized Solar Cell ( DSSC) technology. Deep eutectic solvents which have become a rival to ionic fluids with their ability to reach high conductivity levels and be produced efficiently and in a cost-effective manner, are an attractive fluid technology. I n this group involving the mixtures presented in the invention , mixtures prepared with Zinc (Zn) and Aluminium (Al) chloride, which have been presented before, have given efficient results. Besides, m ixtures prepared with Zn(N0 ₃ ) ₂ :cholinechloride reached the most efficient conductivity values.

Due to the chemicals they contain , their combustive and toxicity is an important issue of organic solvent based electrolytes. For example; lithium salts used in lithium ion batteries show combustive effect in case of contact with air. For this reason , their production costs are higher than some electrolytes since special attention and atmospheric conditions are required in their production. Other organic solvent based electrolytes can be dangerous in terms of the environment and human health since they contain acid and/or base components. Due to the problems referred above, the storage mediums where these electrolytes take place require outer casings. Also by the use of the materials required for the casing, total weight of these storage devices and hence, their production costs increase. Besides, it poses an obstacle to the production of storage devices in free form and/or flexible. This restricted condition was overcome through ionic fluids. The conductivity levels' being above 1 0mS/cm allowed the stored energy density to increase and be charged rapidly. Having low vapor pressures and not reacting easily, ensured them to be more resistant to external factors.

However; the fact that the production of ionic fluids comprises complicated steps and the expensiveness of the chem icals used prevented them to be used in practice. For example; the necessity of vacuum or inert atmosphere in the production step causes the output to be lower with respect to unit of time.

Deep Eutectic Solvents present a solution close to the performance of ionic fluids with a relatively much easier production process. These solvents made up with the metallic salts used and hydrogen donors, however, show a conductivity a little lower than ionic fluids. Com monly, choline-chloride and urea have been used in these studies by mixing into metal salts.

I n the following studies, these conductivity levels were enhanced with the m ixture of zinc nitrate (Zn(N0 ₃ ) ₂ ) salt : Choline-Chloride and reached 23mS/cm at room temperature. This value is able to compete with the present ionic fluids. Besides, it has an edge over ionic fluids since the chem icals used as input and the production process is more favourable. However, increasing this value further will provide for reaching efficient results in the implementation of the production of electricity with DSSC, in automotive, electronics and other areas in need of electrical energy storage.

The following documents were encountered when the inventions resembling said invention were investigated:

• WO0226701 A2: l n this patent document, the ionic compounds in liquid phase at low temperatures and their preparation are described. I n the preparation of said ionic fluids, urea or ethylene glycol is present. US2012082903A1 : l n this patent document, new ionic fluids for use in electrolytes, capacitors and electrochem ical devices such as lithium ion batteries is described.

US8518298A:The invention of this patent document is related to eutectic mixtures containing multivalent metal ions. I n the invention , zinc nitrate is also used in the preparation of eutectic mixtures and this mixture is also of low temperature ionic fluids. Liana Anicai et al . : I n this document ; choline-chloride based ionic fluids are mentioned.

Brief Description of the I nvention and I ts Objectives

Nitrate salts of transition metals zinc (Zn) and aluminium (Al) are more viscose at room temperature since they have lower melting points compared to chlorine salts used in the previous studies. For this reason , zinc nitrate (Zn(N0 ₃ ) ₂ ) : Choline-Chloride m ixture gives a higher conductivity value compared to other mixtures.

I n the subject invention , conductivity levels of mixtures where ethylene glycol was used instead of choline-chloride climbed up even higher. Besides, the preparation , cost and performance of Zn(N0 ₃ ) ₂ : Etilen Glycol ( EG) mixture from ionic fluids which have been developed in the study relating to the invention gives a better result than Zn(N0 ₃ ) ₂ :CholineChloride mixture.

I n addition to this, the aluminium nitrate (AI(N0 ₃ ) ₃ ) salt used in this study for the first time, was found to be more successful compared to other solvents at the charge and high energy storage density points because of high load carrier complex aluminium ions it contains. For this reason , AI(N0 ₃ ) ₃ :CholineChloride, AI( N0 ₃ ) ₃ : Urea and AI(N0 ₃ ) ₃ : EG is present among the m ixtures presented. These m ixtures give results double the conductivity value Zn(N0 ₃ ) ₂ : CholineChloride mixture has given .

While the abovementioned mixtures can be implemented to the present battery technology and super capacitors, since they do not contain toxic and combustive materials, they can be packed without requiring casing and therefore, can be used in flexible storage means. Also in solar battery usages, the abovementioned mixtures can be used. Hence, electricity as a result of photochemical effect can be obtained by application between the electrodes which will capture light. Due to their conductivity levels being high and they are prepared in an easy manner, by the specified mixture, it can allow the production of cost-effective and efficient solar batteries.

Brief Description of t he Draw ings Figure 1 : Conductivity Measurements.

Detailed Description of the I nvent ion

I n the invention , by mixing aluminium nitrate and zinc nitrate salts with choline chloride, urea or ethylene glycol, ionic fluids are obtained. Details regarding the preparation of m ixtures presented as divided into two groups are given below:

(A) Zn(N0 ₃ ) ₂ salt is mixed with particular proportions of ethylene glycol ( EG) . Mole ratios vary between 4: 1 and 1 :5 for Zn(N0 ₃ ) ₂ : EG. For example, conductivity level in the m ixture having 3 : 1 ratio at 20°C is 32 mS/cm . I n the mixture having 1 :2 ratio, 37 mS/cm conductivity level is presented.

The mixture is prepared by stirring in the range of 70-120°C for 70-1000 revolutions/ minute. During the procedure, the effect of humidity should be avoided. The stirring is continued until a colourless and viscose fluid is obtained. This duration varies between 10 m inutes and 2 hours according to mixture proportions.

( B) AI(N0 ₃ ) ₃ salt is m ixed with particular proportions of choline-chloride, urea and/or ethylene glycol. With these m ixtures, conductivity levels up to 52 mS/cm have been reached.

1 ) Mole ratios vary between 4: 1 and 1 :5 for AI(N0 ₃ ) ₃ : CholineChloride. The m ixture is prepared by stirring in the range of 70- 120 °C for 70- 1000 revolutions/minute. During the procedure, the effect of humidity should be avoided. The stirring is continued until a colourless and viscose fluid is obtained. This duration varies between ten m inutes and two hours according to mixture proportions.

2) Mole ratios vary between 4: 1 and 1 :5 for AI(N0 ₃ ) ₃ : Urea.

The m ixture is prepared by stirring in the range of 70- 120 °C for 70- 1000 revolutions/minute. During the procedure, the effect of humidity should be avoided. The stirring is continued until a colourless and viscose fluid is obtained. This duration varies between ten m inutes and two hours according to mixture proportions.

3] Mole ratios vary between 4: 1 and 1 :5 for AI(N0 ₃ ) ₃ : EG.

The mixture is prepared by stirring in the range of 70-120°C for 70-1000 revolutions/ minute. During the procedure, the effect of humidity should be avoided. The stirring is continued until a colourless and viscose fluid is obtained. This duration varies between ten minutes and two hours according to mixture proportions.

After the preparations of aforementioned eutectic solutions, for implementations requiring low vapor pressure and high conductivity, addition of purified water to the prepared solutions can be made. Solution : Purified Water volume ratios vary between 1 :20 and 6: 1 .

I t was observed that in the use of ionic fluids prepared in relation to the invention in storage devices where zinc and aluminium electrodes were used, it provided further increase in energy density.

Amongst which :

· Zinc/ Aluminium-Air batteries

• Zinc/ Aluminium-Lead batteries

• Zinc/ Aluminium-Carbon batteries

• Zinc/ Aluminium-Carbon Super capacitors

• Lead/ Lead and Carbon/ Lead batteries takes place.

These solutions can also be used in fluid solar batteries, aluminium coating. They are suitable for such potential applications, even if they would be heated via high electric current density, they do not decompose, since they have very low vapor pressure.