KR102186946B1 - Redox flow battery comprising vitamin as electrode active material - Google Patents

Abstract

The present invention relates to a redox flow battery comprising vitamin B12 as an active material and, more specifically, to a redox flow battery which can be used as an energy source for a device inserted into the body.

Description

Redox flow battery containing vitamins as an electrode active material {REDOX FLOW BATTERY COMPRISING VITAMIN AS ELECTRODE ACTIVE MATERIAL}

The present disclosure relates to a redox flow cell comprising vitamin B ₁₂ as an active material and a cardiac pacemaker comprising the same.

Redox Flow Battery (RFB) is a large-scale energy storage device, attracting attention as a key technology for renewable energy such as solar energy and wind energy. Unlike conventional lithium and sodium secondary batteries, in the case of a redox flow battery, the active material is dissolved in the electrolyte solution, and each active material undergoes a redox reaction in the positive electrode and the negative electrode. Have a mechanism. The capacity of the battery is determined by the oxidation-reduction reaction of the electrolyte supplied from the external storage, and the capacity of the entire battery can be adjusted by controlling the size of the external storage. In addition, since the redox couple (redox couple), which is an active material, occurs on the surfaces of the positive and negative electrodes, the lifespan of the battery compared to conventional batteries such as lithium ion batteries undergoing a reaction in which ions are inserted/desorbed into the electrode active material. It has the advantage of being longer. The overall structure of this redox flow battery is shown in FIG. 1.

On the other hand, patients with abnormal heart rhythm, especially those who have shortness of breath due to an abnormally slow heart rate, and who cause dizziness, palpitations, and fainting, may receive treatment by inserting a pacemaker into the body. The pacemaker creates electrical impulses regularly and delivers them to the heart through special conductors inserted into the heart so that the patient's heart can beat regularly and on time. These pacemakers require a source of energy to produce regular pulses. Early models of pacemakers were powered by mercury-zinc batteries and operated for 2 to 3 hours. In 1973, a lithium iodide fuel cell was developed that could last for about six years.

In the United States alone, more than 100,000 pacemakers are implanted in patients each year, and modern pacemakers include a pulse generator, circuitry programmed to monitor the heart rate and deliver stimulation, and a lithium iodide battery that lasts 7 to 15 years. In addition, Venkateswara Sarma Mallela, V. Ilankumaran and N. Srinivasa Rao, Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 4(4): 201-212 (2004) describe the trends of batteries used in pacemakers. Most of them are lithium batteries using lithium materials as an active material. Therefore, although the pacemaker is a device that is inserted into the body, a battery containing lithium is used, and a battery made of only materials that have proven safety in the human body has not been developed yet.

Under this background, the present inventors developed a redox flow battery consisting of vitamins and PBS, which have been proven to be safe in the body.

Venkateswara Sarma Mallela, V. Ilankumaran and N. Srinivasa Rao, Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 4(4): 201-212 (2004)

The present disclosure is to provide a redox flow battery including vitamin B ₁₂ as an active material in order to provide a battery made of a material safe in the body.

As a first aspect according to the present disclosure, there is provided a redox flow battery comprising vitamin B ₁₂ as an active material.

Hereinafter, the present disclosure will be described in detail.

It is understood that the term “about” refers to a range of numbers that one of ordinary skill in the art would consider equivalent to the stated value in terms of achieving the same function or result.

The pacemaker is used for artificial heart implanted in the body, and is a device that generates a programmed electrical beat and delivers it to the heart to obtain a therapeutic effect. It is used for patients who have shortness of breath and heart failure due to an abnormally slow heart rate and lack of blood to the cerebrum, causing dizziness or fainting, and low cardiac output. That is, when the heartbeat is not appropriate, it is a device that sends a small amount of electrical stimulation to the heart to maintain an appropriate heart rate, thereby helping to perform activities and movements that were previously impossible due to strength. These pacemakers are inserted into the body, and conventional batteries used in pacemakers are mostly batteries using lithium as an active material (Venkateswara Sarma Mallela, V. Ilankumaran and N. Srinivasa Rao, Indian Pacing and Electrophysiology Journal (ISSN 0972). -6292), 4(4): 201-212 (2004)). However, since such lithium is not safe in the body, it will have a very adverse effect on the patient when the material of the battery leaks and enters the body. Therefore, there is a need for a battery made of materials that have been confirmed to be more safe.

The present disclosure has confirmed that vitamins can be used as an active material, and to provide a redox flow battery using these vitamins as an active material.

Other Vitamins in the present disclosure and can be used universally If vitamin which can cause, that is, the electrode reaction, which can be used as an electrode active material, was used preferably vitamin B _12.

[Formula 1]

Vitamin B ₁₂ can have three oxidation states depending on the oxidation state (+1/+2/+3) of cobalt, the central metal. The reduction potential due to this change in the oxidation state of vitamin B ₁₂ is as follows:

^{_{Vb 12 (III) + e -}} → Vb 12 (II) E 0 = 0.07 V (vs Ag / AgCl)

^{_{Vb 12 (II) + e -}} → Vb 12 (I) E 0 = -0.81 V (vs Ag / AgCl)

Therefore, vitamin B ₁₂ in a desired oxidation state can be used as an active material according to the redox potential of vitamin B ₁₂ . In one embodiment, vitamin B ₁₂ (I) was used as an active material.

The redox flow battery according to this disclosure both in the positive electrode active material and negative electrode active material is also possible to use the vitamin B _12, and it is also possible for only one of the positive electrode active material and negative electrode active material using the vitamin B _12. In this case, it can be prepared by using the reaction of B ₁₂ (II)/(III) in the positive electrode and the reaction of B ₁₂ (I)/(II) in the negative electrode. On the other hand, when the only one of the positive electrode active material and negative electrode active material using the vitamin B _12, and the other active material may be selected from substances in safety is demonstrated in vivo as in the vitamin B _12. In one embodiment, vitamin B12, specifically vitamin B12 (I) was used as the negative active material, and ferricyanide Fe(CN) ₆ (III) was used as the positive active material. Ferricyanide can be reduced to ferrocyanide Fe(CN) ₆ (II), its reduction potential is as follows:

_{Fe (CN) 6 (III)} + e - → Fe (CN) 6 (II) E 0 = 0.25 V (vs Ag / AgCl)

Thus, the equation of the electrode reaction in this example is as follows:

_{Cathode: Fe (CN) 6 (III} ) + e - → Fe (CN) 6 (II) E 0 = 0.25 V (vs Ag / AgCl)

Cathode: Vb₁₂ (I) →Vb₁₂ (II) +e^- E⁰ = 0.81 V (vs Ag/AgCl)

Overall electrode reaction formula: Fe(CN) ₆ (III) + Vb ₁₂ (I) → Fe(CN) ₆ (II) + Vb ₁₂ (II) E=1.06 V

The concentration of the vitamin active material may be about 1 mM to about 100 mM, preferably about 5 mM to about 15 mM. The concentration of ferricyanide may be about 1 mM to about 100 mM, preferably about 40 mM to about 60 mM.

On the other hand, it is also possible to directly manufacture a redox flow battery including a negative electrode electrolyte containing B ₁₂ (I) as a negative electrode active material and a positive electrode electrolyte containing Fe(CN) ₆ (III) as a positive electrode active material, and B ₁₂ It is also possible to manufacture the redox flow battery using the electrolyte solution containing (III). Specifically, since vitamin B ₁₂ is easily oxidized to oxygen in the air, it is mostly present in the form of vitamin B ₁₂ (III). Accordingly, a redox flow battery including B ₁₂ (I) as a negative active material may be obtained through a process of activating B ₁₂ (III) to obtain vitamin B ₁₂ (I).

In an embodiment, a redox flow battery including B ₁₂ (I) as a negative active material was obtained through a first activation step and a second activation step. Specifically, the first activation step is a process in which Fe(CN) ₆ (II) and vitamin B ₁₂ (III) are added to each electrolyte and voltage is applied to cause the following electrode reaction:

Fe(CN)₆(II) →Fe(CN)₆(III) + e^- E⁰ = 0.25 V (vs Ag/AgCl)

^{_{Vb 12 (III) + e -}} → Vb 12 (II) E 0 = -0.07 V (vs Ag / AgCl)

Thereafter, through a second activation step, an electrolyte solution containing B ₁₂ (I) as a negative active material may be obtained. Specifically, the second activation step is a process of causing the following electrode reaction by applying a voltage again to each of the active materials including Fe(CN) ₆ (II) and Vb ₁₂ (II) obtained previously.

Fe(CN)₆(II) →Fe(CN)₆(III) + e^- E⁰ = 0.25 V (vs Ag/AgCl)

^{_{Vb 12 (II) + e -}} → Vb 12 (I) E 0 = -0.81 V (vs Ag / AgCl)

At this time, since Fe(CN) ₆ (II) must perform the same reaction twice, the initial concentration of Fe(CN) ₆ (II) may be more than twice the concentration of the initial B ₁₂ (III). Specifically, the concentration of Fe(CN) ₆ (II) may be 2 to 10 times, 2 to 8 times, 3 to 7 times, or about 5 times the concentration of the initial B ₁₂ (III). At this time, the concentration of B ₁₂ (III) may be about 1 mM to about 100 mM, preferably about 5 mM to about 15 mM. The concentration of Fe(CN) ₆ (II) may be about 1 mM to about 100 mM, preferably about 40 mM to about 60 mM.

Both the positive electrode and the negative electrode electrolyte of the redox flow battery of the present disclosure have a neutral pH, for example, a pH of 6 to 8, and may be a safer electrolyte. In order to create such a neutral pH, both electrolytes may contain a buffer material, and specifically, may contain PBS as a buffer material. Since PBS is also a material whose safety has been confirmed in vivo, an electrolyte solution having a neutral pH can be provided by using it.

The redox flow battery according to the present disclosure may be an aqueous redox flow battery having an aqueous electrolyte. Accordingly, an aqueous solvent is used as the solvent, and the aqueous solvent may be water or a mixture of water and a hydrophilic solvent. Here, the hydrophilic solvent is a hydrophilic solvent whose safety has been proven in the body such as ethanol.

The electrolyte of the redox flow battery according to the present disclosure may further include an auxiliary electrolyte in addition to the active material, a PBS buffer material, and an aqueous solvent. At this time, the auxiliary electrolyte may likewise be a salt material that has proven safety in the body.

The battery may further include a positive electrode, a negative electrode, and a separator positioned between the positive electrode and the negative electrode. In addition, it may include a positive electrolyte reservoir and a negative electrolyte reservoir each accommodating the positive electrolyte solution and the negative electrolyte solution, and may include a pump for pumping them respectively. The pump may be set to be in an operating condition of 10 to 50 rpm, preferably 20 to 40 rpm, and set to a flow rate condition of 10 to 50 mL/min, preferably 20 to 30 mL/min.

As the separator, an ion exchange membrane used in a conventional redox flow battery may be used without limitation. For example, it may be a fluorine-based polymer, a partially fluorine-based polymer, or a hydrocarbon-based polymer, and more specifically, perfluorosulfonic acid-based polymer, hydrocarbon-based polymer, aromatic sulfone-based polymer, aromatic ketone-based polymer, polybenzimidazole-based polymer, polystyrene-based polymer, poly Ester polymer, polyimide polymer, polyvinylidene fluoride polymer, polyethersulfone polymer, polyphenylene sulfide polymer, polyphenylene oxide polymer, polyphosphagen polymer, polyethylene naphthalate polymer, poly Ester polymer, doped polybenzimidazole polymer, polyether ketone polymer, polyphenylquinoxaline polymer, polysulfone polymer, sulfonated polyarylene ether polymer, sulfonated polyetherketone polymer, sulfonated Consisting of polyetheretherketone polymer, sulfonated polyamide polymer, sulfonated polyimide polymer, sulfonated polyphosphazene polymer, sulfonated polystyrene polymer, and radiation polymerized sulfonated low-density polyethylene-g-polystyrene polymer Homo copolymer, alternating copolymer, random copolymer, block copolymer, multiblock copolymer of one or more polymers selected from the group And it may be selected from a graft copolymer (Grafting copolymer). The separator may be an anion exchange membrane or a porous membrane.

The anode and cathode of the present invention are each independently made of gold (Au), tin (Sn), titanium (Ti) platinum (Pt), platinum-titanium (Pt-Ti), iridium oxide-titanium (IrO-Ti), and carbon. It may be any one or more selected from the group consisting of. Electrodes must have excellent electrical conductivity and mechanical strength, and must be chemically and electrochemically stable. In addition, when applied to a battery, it must be able to show high efficiency, be inexpensive, and must be a material in which oxidation/reduction reactions with an active material are reversible. In consideration of these criteria, as above, from the group consisting of gold (Au), tin (Sn), titanium (Ti), platinum-titanium (Pt-Ti), iridium oxide-titanium (IrO-Ti), and carbon materials. Any one or more selected may be used as the electrode, and other materials that satisfy the above criteria and maintain stability in acid and base may be used as the electrode. The carbon material has advantages of inexpensive price, high chemical resistance in acid and base electrolytes, and easy surface treatment. A carbon-based electrode may be advantageous in consideration of the hydrogen generation reaction. In particular, carbon felt among carbon materials has advantages in that it has chemical resistance, stability in a wide voltage range, and high strength characteristics. However, if an electrode is manufactured with only carbon and graphite, it is fragile, so to overcome this, polyvinylidene (PVDF), high density polyethylene (HDPE), polyvinyl A carbon polymer composite electrode is used by mixing a binder such as polyvinyl acetate (PVA) or polyolefine with a conductive material such as carbon black and graphite fiber. Can be.

The redox flow battery according to the present disclosure can be used as a battery for a device inserted into the body because all substances contained in the electrolyte are safe materials in the body. Specifically, it can be used as a battery for a pacemaker of an artificial heart (see FIG. 2).

As a second aspect according to the present disclosure, there is provided a method of manufacturing the redox flow battery. Specifically, the manufacturing method

Preparing a negative electrolyte solution containing vitamin B ₁₂ (III);

Preparing a positive electrode electrolyte containing Fe(CN) ₆ (II);

Assembling a redox flow battery including the negative electrolyte and the positive electrolyte;

Applying a voltage to the battery to perform a first activation step to obtain a negative electrolyte solution containing vitamin B ₁₂ (II); And

And performing a second activation step by applying a voltage to the battery to obtain a negative electrolyte solution containing vitamin B ₁₂ (I).

Each material and process included in the manufacturing method are the same as those described in the redox flow battery according to the present disclosure.

In a third aspect according to the present disclosure, there is provided a pacemaker comprising a redox flow battery according to the present disclosure. The redox flow battery may be safer and less dangerous than a lithium battery when an active material and a buffer solution included in the electrolyte are all safe materials in the body. A specific structure of the pacemaker may have the structure described in Korean Patent Registration No. 10-0844119.

The redox flow battery according to the present disclosure can be used as an energy source of a device inserted into the body because all substances contained in the electrolyte are safe materials in the body. Specifically, when used as a battery for a pacemaker, it is much safer because a battery made of a safer material is used.

1 shows the structure of a typical redox flow battery.
2 shows the structure of the artificial heart pacemaker including a redox flow battery according to the present disclosure as the structure of the artificial heart pacemaker.
3 shows a cyclic voltammogram using an Ag/AgCl reference electrode of vitamin B ₁₂ identified in Experimental Example 1.
4 shows a circulating voltage current curve using an Ag/AgCl reference electrode of Fe(CN) ₆ identified in Experimental Example 2.
5 shows a voltage curve over time of a redox flow battery according to the present disclosure identified in Examples.
6 shows the capacity and efficiency according to the number of cycles of the redox flow battery according to the present disclosure as identified in Examples.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. However, since various changes may be applied to the embodiments, the scope of the patent application is not limited or limited by these embodiments. It should be understood that all changes, equivalents, or substitutes to the embodiments are included in the scope of the rights.

The terms used in the examples are used for illustrative purposes only and should not be interpreted as limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiment belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

In addition, in the description with reference to the accompanying drawings, the same reference numerals are assigned to the same components regardless of the reference numerals, and redundant descriptions thereof will be omitted. In describing the embodiments, when it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the embodiments, the detailed description thereof will be omitted.

Throughout the present specification, "%" used to indicate the concentration of a specific substance is (weight/weight)% for solids/solids, (weight/volume)% for solids/liquids, and Liquid/liquid is (vol/vol) %.

Preparation Example 1: Vitamin B ₁₂ Preparation of an electrolyte solution containing as an active material

0.2 g of vitamin B ₁₂ was added to 15 ml of PBS 1X (pH 7.4) and mixed to prepare a ₁₀ mM vitamin B ₁₂ negative electrolyte.

Preparation Example 2: Fe(CN) ₆ Preparation of an electrolyte solution containing as an active material

0.363 g of sodium ferrocyanide (II) was added to 15 ml of PBS 1X (pH 7.4) and mixed to prepare a ferrocyanide positive electrode electrolyte having a concentration of 50 mM.

Experimental Example 1: Vitamin B ₁₂ Redox reactivity of the electrolyte solution containing

The electrochemical properties of the electrolyte solution of Preparation Example 1 were subjected to a cyclic voltammetry experiment using a three-electrode method (reference electrode: Ag/AgCl electrode, counter electrode: Pt wire, working electrode: Glassy Carbon Electrode). Cyclic voltammetry was carried out in the range of -1.5 to 0.7 V (vs. Ag/AgCl) at a scan rate of 10 mV/s. This is shown in FIG. 3.

In the electrochemical properties measured by the cyclic voltammetry of Preparation Example 1, two redox reactions were observed. The reduction of the → Vb ₁₂ (I) ^- in a first _{-0.07V Vb 12 (III) + e} - → Vb 12 (II) and was born is displayed such a reduction reaction followed by ₁₂ (II) + e at -0.81V Vb appear. When the next scan proceeds in the positive direction, an oxidation reaction of Vb ₁₂ (I) → Vb ₁₂ (II) + e ^- appeared at -0.81 V, and Vb ₁₂ (II) → Vb ₁₂ (III) at -0.07 V again. An oxidation reaction such as + e ^- appeared. As described above, it was confirmed that Vb ₁₂ can stably perform two redox reactions in the PBS electrolyte.

Experimental Example 2: Fe(CN) ₆ Redox reactivity of an electrolyte containing as an active material

The electrochemical properties of the electrolyte of Preparation Example 2 were subjected to a cyclic voltammetry experiment using a three-electrode method (reference electrode: Ag/AgCl electrode, counter electrode: Pt wire, working electrode: Glassy Carbon Electrode). Cyclic voltammetry was carried out in the range of -1.5 to 1.0 V (vs. Ag/AgCl) at a scan rate of 10 mV/s. This is shown in FIG. 3.

In the electrochemical properties measured by the cyclic voltammetry of Preparation Example 2, one redox reaction was observed. Based on 0.25V (vs. Ag/AgCl), redox reactions such as Fe(CN) ₆ (II) ↔ Fe(CN) ₆ (III) + e ^- were shown. In this way, it was confirmed that Fe(CN) ₆ can stably perform a redox reaction in the PBS electrolyte. This is shown in Figure 4.

Example: Preparation of redox flow battery

A battery was manufactured using the negative electrode electrolyte of Preparation Example 1 and the positive electrode electrolyte of Preparation Example 2. Carbon felt was used as the electrode of the battery, and a fluorine-based polymer separator was used as the separator.

Each electrolyte was put into the cathode and anode electrolyte storage tanks, respectively, and then connected to the complete cell through a tygon tubing, and the electrolyte was flowed from an external pump.

While charging/discharging the battery at a current density of 1 mA/cm ² , the voltage over time was measured. This is shown in Figure 5. First Vb ₁₂ from 0.6V to 0.9V (III) + e ^- The activation reactions → Vb ₁₂ (II) were carried out. Immediately following, the charging step of the battery of the present invention proceeded from 0.9V to 1.2V, and the discharge step proceeded from 1.2V to 0.6V again. Therefore, it was confirmed that vitamin B ₁₂ can be used as a normal charge/discharge active material under PBS electrolyte conditions.

In addition, the capacity and efficiency according to the number of cycles were measured and shown in FIG. 6. Stable cycling continued with a high efficiency of about 80% from 2 cycles excluding the initial activation step, and the capacity was also 350 mAh L ^-1 , so cycling proceeded without significant capacity reduction, confirming the stability of the battery.

As described above, although the embodiments have been described by the limited drawings, a person of ordinary skill in the art can apply various technical modifications and variations based on the above. For example, the described techniques are performed in a different order from the described method, and/or components such as a system, structure, device, circuit, etc. described are combined or combined in a form different from the described method, or other components Alternatively, even if substituted or substituted by an equivalent, an appropriate result can be achieved.

Therefore, other implementations, other embodiments and claims and equivalents fall within the scope of the following claims.

Claims (5)

A pacemaker comprising a redox flow battery, which is a battery of a device inserted into the body,
The redox flow battery
Vitamin B ₁₂ is included as an active material of the anode electrolyte and ferricyanide is included as an active material of the cathode electrolyte; or
To contain vitamin B ₁₂ as an active material of the positive electrolyte and negative electrolyte,
Pacemaker.
The pacemaker of claim 1, wherein the electrolyte solution of the redox flow battery contains PBS (Phosphate-buffered saline).
The heart pacemaker of claim 1, wherein the redox flow battery contains vitamin B ₁₂ as an active material of the negative electrolyte and ferricyanide as an active material of the positive electrolyte.
The pacemaker of claim 1, wherein both the positive and negative electrolytes of the redox flow battery have a pH of 6 to 8. delete

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