KR102319109B1 - Hybrid sodium-carbon dioxide secondary battery capable of obtaining energy storage along with high value-added product by electrochemical carbon dioxide reduction and secondary battery system comprising the same - Google Patents

Abstract

The present invention relates to a hybrid sodium-carbon dioxide secondary battery capable of obtaining a high value-added product through an electrochemical reduction reaction of carbon dioxide with energy storage and a secondary battery composite system including the same, and more particularly, the hybrid sodium-carbon dioxide of the present invention In a secondary battery, the negative electrode contains sodium metal and an organic electrolyte and the positive electrode contains a metal-carbon composite catalyst and an aqueous electrolyte. .
In addition, the secondary battery composite system of the present invention includes an energy storage system and the hybrid sodium-carbon dioxide secondary battery, so that various high-value-added carbon compounds and electrical energy can be simultaneously obtained during discharging in one device, and the produced electrical energy is flexible It has the advantage of being able to efficiently use energy by storing and converting it.

Description

A hybrid sodium-carbon dioxide secondary battery capable of obtaining high value-added products through the electrochemical reduction reaction of carbon dioxide with energy storage and a secondary battery complex system including the same ADDED PRODUCT BY ELECTROCHEMICAL CARBON DIOXIDE REDUCTION AND SECONDARY BATTERY SYSTEM COMPRISING THE SAME}

The present invention relates to a hybrid sodium-carbon dioxide secondary battery capable of obtaining a high value-added product through an electrochemical reduction reaction of carbon dioxide with energy storage and a secondary battery composite system including the same.

As the problem of abnormal climate due to global warming intensifies, a global policy to reduce _{CO 2 emission, which is one of the causes, is being implemented.} In Korea, the greenhouse gas emission trading system has been in effect since 2015. In particular, in accordance with the Paris Agreement on the new climate regime signed in Paris on December 12, 2015, Korea will reduce its emissions by 37% compared to BAU (Business AS Usual) by 2030. have a duty to do

However, in the process using fossil fuels, _{by-product gases including CO 2} are inevitably generated, and the domestic energy business that can replace fossil fuels is very insignificant. Therefore, the need for research on technologies to capture, store and convert the emitted CO _{2 is emphasized.}

Currently, _{the technology for converting CO 2} into a high-value-added carbon compound is difficult to commercialize because it requires conditions such as high temperature and pressure. In recent academic electrochemical reduction of CO ₂ (CO ₂ RR; CO ₂ reduction reaction) is spotlighted as one of the CO ₂ recycling strategy. When CO ₂ RR is used, CO ₂ that is difficult to decompose can be directly removed. In addition, it is possible to obtain economic value added by carbon monoxide (CO), formic acid (HCOOH) and various hydrocarbon products generated in the _{CO 2 removal process.} In particular, carbon monoxide (CO) and formic acid (HCOOH) are expected to become major products in the _{electrochemical CO 2 conversion business by showing high economic feasibility compared to the production price.}

However, CO ₂ is continuously emitted from petrochemical processes and steel processes, but in the existing CO ₂ RR system, surplus electrical energy is generated irregularly, so the generated electrical energy cannot be used flexibly and efficiently. In addition, there is a problem that high-cost electrical energy is required to electrochemically reduce _{CO 2 .} To solve this problem, a study on a system that can efficiently operate the energy required _{for CO 2} RR and a study on developing a catalyst material with good activity and selectivity for _{CO 2 RR are being conducted at the same time.}

Among the methods that can utilize CO _{2 , metal-CO 2} batteries are receiving a lot of attention. Metal-CO ₂ started with the study of metal-air batteries. Metal-air batteries have a high energy density, so much research has been done in recent decades. However, the metal-air battery has problems with capacity and stability that are attenuated compared to when pure oxygen is injected as carbonate is formed from _{CO 2 in the air when actually air is injected.}

After discovering that the capacity of a metal-air battery increased by a factor of three when carbon dioxide was added to oxygen in a certain portion, Archer's group developed a _{primary lithium-CO 2 battery whose capacity changes with temperature.} It was confirmed that CO ₂ was fixed to Li ₂ CO _{3 and C during discharge.} In addition, Zhou group has developed _{a rechargeable lithium-CO 2} battery using an anode that can promote the decomposition _{of Li 2} CO _{3 .} Since then, many groups have focused on rechargeable metal-CO ₂ batteries, _{represented by lithium-CO 2 .}

Currently, metal-CO ₂ batteries exhibit high operating voltages, high energy density, and lifetimes of more than tens of cycles. However, there is a discharge product is limited to a carbon (carbon), carbonates (carbonate), oxylate (oxalate) due to occur without participation of the proton electrochemical reduction of CO ₂ (CO ₂ RR) in the organic electrolyte during discharging. That is, in a metal-CO ₂ battery using an organic electrolyte, high value-added carbon compounds such as hydrocarbons, acids, and alcohols have a limitation in that it is impossible to produce them.

The following non-patent documents 1 and 2 show a low voltage of 0.5 V or less due to the characteristics of Zn metal, although _{CO 2 RR occurs during discharging in the anode portion, thereby limiting efficient charging and discharging as a secondary battery.}

On the other hand, theoretically, water is the perfect medium to provide protons to enable _{CO 2 RR.} In fact, it has been proven that many noble metals, transition metals, and carbon electrochemical catalysts can produce high value-added products by smoothly forming _{CO 2 RR in water.} In addition, water has the advantage of being suitable as an electrolyte because it is less expensive and more environmentally friendly than organic electrolytes.

Therefore, in order to improve the inefficiency of electric energy of the _{existing CO 2} RR secondary battery and to obtain various products, research and development for a new metal-carbon dioxide secondary battery with good activity and selectivity _{for CO 2 RR has been applied.} necessary.

Xu, S.; Das, S. K.; Archer, L. A. The Li-CO2 battery: a novel method for CO2 capture and utilization. RSC Adv. 2013, 3, 6656-6660. Xie, Z.; Zhang, X.; Zhang, Z.; Zhou, Z. Metal-CO2 Batteries on the Road: CO2 from Contamination Gas to Energy Source. Adv. Mater. 2017, 29, 1605891.

In order to solve the above problems, an object of the present invention is to provide a hybrid sodium-carbon dioxide secondary battery capable of obtaining various high value-added products during discharge.

Another object of the present invention is to provide a secondary battery composite system including the hybrid sodium-carbon dioxide secondary battery capable of storing energy and obtaining a high value-added product at the same time.

Another object of the present invention is to provide a method for producing a carbon compound of carbon dioxide using the hybrid sodium-carbon dioxide secondary battery.

The present invention provides a first current collector, an anode comprising a sodium metal and an organic electrolyte; a second current collector, a metal-carbon composite catalyst, and a cathode containing an aqueous electrolyte; and a solid electrolyte positioned between the negative electrode part and the positive electrode part; hybrid sodium-carbon dioxide including a secondary battery.

The metal-carbon composite catalyst may be one in which metal nanoparticles are bound in a weight ratio of 1:9 to 9:1 on a carbon support.

The carbon support may be at least one selected from carbon black, Ketjen black, acetylene black, graphite, carbon nanotubes, carbon nanofibers, graphene oxide and reduced graphene oxide.

The metal nanoparticles may have a diameter of 1 to 30 nm, and may be at least one selected from gold, silver, copper, and tin.

The aqueous electrolyte is selected from sodium hydrogen carbonate (NaHCO ₃ ), sodium hydroxide (NaOH), sodium sulfate (Na ₂ SO ₄ ), sodium nitrate (NaNO ₃ ), sodium chloride (NaCl) and sodium carbonate (Na ₂ CO ₃ ) There may be more than one type.

The hybrid sodium-carbon dioxide secondary battery may be operated by injecting carbon dioxide into the aqueous electrolyte of the positive electrode.

When the hybrid sodium-carbon dioxide secondary battery is charged, a sodiumization reaction as shown in Scheme 1 below may occur in the negative electrode portion, and an oxygen evolution reaction (OER) may occur in the positive electrode portion as shown in Scheme 2 below.

[Scheme 1]

Na ⁺ + e ^- → Na

[Scheme 2]

4OH ^- → O ₂ + 2H ₂ O + 4e ^-

When the hybrid sodium-carbon dioxide secondary battery is discharged, a desodium reaction as shown in Scheme 3 below occurs in the negative electrode part, and at least one carbon dioxide reduction reaction (CO ₂ RR) selected from the following Reaction Formulas 4 to 7 is performed in the anode part. can happen

[Scheme 3]

Na → Na ⁺ + e ^-

[Scheme 4]

CO ₂ + 2H ⁺ + 2e ^- → CO + H ₂ O

[Scheme 5]

CO ₂ + 2H ⁺ + 2e ^- → HCOOH

[Scheme 6]

2CO ₂ + 12H ⁺ + 12e ^- → C ₂ H ₄ + 4H ₂ O

[Scheme 7]

2CO ₂ + 12H ⁺ + 12e ^- → C ₂ H ₅ OH + 3H ₂ O

One or more carbon compounds selected from carbon monoxide (CO), formic acid (HCOOH), ethylene (C ₂ H ₄ ), and ethanol (C ₂ H _{5 OH) may be produced by the carbon dioxide reduction reaction.}

The metal-carbon composite catalyst is one in which metal nanoparticles are bound on a carbon support in a weight ratio of 4:6 to 6:4, and the carbon support is carbon black, Ketjen black, acetylene black, graphite, carbon nanotubes, carbon nanofibers. , graphene oxide and at least one selected from reduced graphene oxide, the metal nanoparticles have a diameter of 1 to 30 nm, gold, tin, or a mixture thereof, and the aqueous electrolyte is sodium hydrogen carbonate (NaHCO ₃ ) , sodium hydroxide (NaOH) and at least one selected from sodium chloride (NaCl), and by injecting carbon dioxide into the aqueous electrolyte of the positive electrode to operate the hybrid sodium-carbon dioxide secondary battery, the hybrid sodium-carbon dioxide secondary battery is During charging, a sodiumization reaction as shown in Scheme 1 below occurs in the anode part, and an oxygen evolution reaction (OER) as shown in Scheme 2 below occurs in the anode part,

[Scheme 1]

Na ⁺ + e ^- → Na

[Scheme 2]

4OH ^- → O ₂ + 2H ₂ O + 4e ^-

When the hybrid sodium-carbon dioxide secondary battery is discharged, a desodium reaction as shown in Scheme 3 below occurs in the negative electrode part, and at least one carbon dioxide reduction reaction (CO ₂ RR) selected from the following Reaction Formula 4 or Scheme 5 in the positive electrode part. will happen,

[Scheme 3]

Na → Na ⁺ + e ^-

[Scheme 4]

CO ₂ + 2H ⁺ + 2e ^- → CO + H ₂ O

[Scheme 5]

CO ₂ + 2H ⁺ + 2e ^- → HCOOH

At least one carbon compound selected from carbon monoxide (CO) and formic acid (HCOOH) may be produced by the carbon dioxide reduction reaction.

In the metal-carbon composite catalyst, metal nanoparticles are bound on a carbon support in a weight ratio of 5:5, the carbon support is carbon black, the metal nanoparticles are gold having a diameter of 7 to 8 nm, and the aqueous electrolyte is sodium hydrogen carbonate (NaHCO ₃ ), and by injecting carbon dioxide into the aqueous electrolyte of the positive electrode to operate the hybrid sodium-carbon dioxide secondary battery, the hybrid sodium-carbon dioxide secondary battery is charged in the negative electrode part as shown in Reaction Formula 1 below Sodiation reaction occurs, and oxygen evolution reaction (OER) as shown in Reaction Formula 2 below occurs in the anode part,

[Scheme 1]

Na ⁺ + e ^- → Na

[Scheme 2]

4OH ^- → O ₂ + 2H ₂ O + 4e ^-

When the hybrid sodium-carbon dioxide secondary battery is discharged, a desodium reaction as shown in Scheme 3 below occurs in the negative electrode part, and a carbon dioxide reduction reaction (CO ₂ RR) as shown in Scheme 4 below occurs in the positive electrode part,

[Scheme 3]

Na → Na ⁺ + e ^-

[Scheme 4]

CO ₂ + 2H ⁺ + 2e ^- → CO + H ₂ O

A carbon compound of carbon monoxide (CO) may be produced by the carbon dioxide reduction reaction.

On the other hand, the present invention provides a secondary battery composite system including the hybrid sodium-carbon dioxide secondary battery.

a carbon dioxide supply unit for supplying carbon dioxide to the hybrid sodium-carbon dioxide secondary battery; an energy storage system (ESS) for storing electric energy generated from the hybrid sodium-carbon dioxide secondary battery; and a reaction product storage unit for storing a carbon compound of carbon dioxide generated from the hybrid sodium-carbon dioxide secondary battery.

In addition, the present invention is a cathode (anode) portion; anode (cathode) part; and a solid electrolyte positioned between the negative electrode and the positive electrode; in the hybrid sodium-carbon dioxide secondary battery comprising: (a) supplying an aqueous electrolyte to the positive electrode in the method for producing a carbon compound of carbon dioxide step; (b) supplying carbon dioxide to the anode part to which the aqueous electrolyte is supplied; and (c) applying a current between the anode part and the cathode part ^{to form hydrogen ions (H +} ) in the anode part, and the hydrogen ions (H ⁺ ) reduce carbon dioxide to produce a carbon compound of carbon dioxide It provides a method for producing a carbon compound of carbon dioxide containing;

In step (c), a current of 1 to 3 mA may be applied between the anode part and the cathode part.

The carbon compound of carbon dioxide may be at least one selected from carbon monoxide (CO), formic acid (HCOOH), ethylene (C ₂ H ₄ ), and ethanol (C ₂ H _{5 OH).}

The carbon compound of carbon dioxide produced in step (c) may be produced with a faradaic efficiency of 55% or more at a current of 1 to 3 mA.

The hybrid sodium-carbon dioxide secondary battery of the present invention contains sodium metal and an organic electrolyte in the negative electrode, and the positive electrode contains a metal-carbon composite catalyst and an aqueous electrolyte. Electrical energy can be obtained at the same time.

In addition, the hybrid sodium-carbon dioxide secondary battery of the present invention contains a metal-carbon composite catalyst having excellent activity and selectivity for the reduction reaction of carbon dioxide in the positive electrode, thereby improving the yield of carbon compounds produced during discharge.

In addition, the secondary battery composite system of the present invention includes an energy storage system and the hybrid sodium-carbon dioxide secondary battery, so that various high-value-added carbon compounds and electrical energy can be simultaneously obtained during discharging in one device, and the produced electrical energy is flexible It has the advantage of being able to efficiently use energy by storing and converting it.

1 is a schematic configuration diagram (a) and an actual configuration photograph (b) of a hybrid sodium-carbon dioxide secondary battery of the present invention.
2 is a transmission electron microscope (TEM) image of the gold nanoparticle-carbon support composite catalyst prepared in Example 1 of the present invention.
3 is a graph showing the Faradaic Efficiency _{of carbon monoxide (CO) and hydrogen (H 2} ) generated by current for the hybrid sodium-carbon dioxide secondary battery prepared in Example 1 of the present invention.
4 is a graph showing the discharge and charge voltage profiles of the hybrid sodium-carbon dioxide secondary battery prepared in Example 1 of the present invention.
5 is a graph showing a galvanostatic discharge-charge cycling curve at 1 mA current for the hybrid sodium-carbon dioxide secondary battery prepared in Example 1 of the present invention.
6 is a graph of the discharge voltage according to the current of the hybrid sodium-carbon dioxide secondary battery prepared in Example 2 of the present invention (a) and the Faradays of formic acid (HCOOH), carbon monoxide (CO) and hydrogen (H ₂ ) It is a graph (b) showing the Faradaic Efficiency.

Hereinafter, the present invention will be described in more detail by way of one embodiment.

In the present invention, Faradaic Efficiency (FE) refers to a ratio of energy used to actually generate organic compounds among energy used to convert carbon dioxide into organic compounds.

The present invention relates to a hybrid sodium-carbon dioxide secondary battery capable of obtaining a high value-added product through an electrochemical reduction reaction of carbon dioxide with energy storage and a secondary battery composite system including the same.

The existing secondary battery system was a method of collecting carbon dioxide in the form of _{sodium bicarbonate (NaHCO 3} ) in the aqueous solution by flowing carbon dioxide into the anode aqueous solution and producing hydrogen when discharging from the anode. _{However, in the present invention, carbon monoxide (CO), formic acid (HCOOH), ethylene (C 2} H ₄ ) or ethanol by a direct reduction reaction of carbon dioxide, rather than the production of hydrogen by capturing carbon dioxide in an aqueous solution at the positive electrode, unlike the conventional secondary battery system. It is designed to obtain high value-added products such as (C ₂ H _{5 OH).}

That is, in the hybrid sodium-carbon dioxide secondary battery of the present invention, the negative electrode contains sodium metal and an organic electrolyte, and the positive electrode contains a metal-carbon composite catalyst and an aqueous electrolyte. A high value-added product can be obtained by direct conversion, and further industrial and economic contributions can be made.

Specifically, the present invention includes a first current collector, a negative electrode (anode) containing a sodium metal and an organic electrolyte; a second current collector, a metal-carbon composite catalyst, and a cathode containing an aqueous electrolyte; and a solid electrolyte positioned between the negative electrode part and the positive electrode part; hybrid sodium-carbon dioxide including a secondary battery.

1 is a schematic configuration diagram (a) and an actual configuration photograph (b) of the hybrid sodium-carbon dioxide secondary battery. Referring to (a) of FIG. 1, the hybrid sodium-carbon dioxide secondary battery is a coin-cell type in an anode part, and is composed of a current collector, sodium metal, and an organic electrolyte, and a house in the cathode part. It is composed of a whole, a metal-carbon composite catalyst and a water-based electrolyte. A NASICON solid electrolyte capable of separating the organic electrolyte of the negative electrode and the aqueous electrolyte of the positive electrode ^{and moving Na +} is positioned between the negative electrode and the positive electrode.

In the hybrid sodium-carbon dioxide secondary battery _{, the secondary battery operates while flowing carbon dioxide (CO 2} ) gas to the aqueous electrolyte of the positive electrode part, and the operated hybrid sodium-carbon dioxide secondary battery causes a desodium reaction in the negative electrode part during discharge. , shows that the reduction reaction of carbon dioxide occurs in the anode part to produce carbon compounds.

The metal-carbon composite catalyst has excellent activity and selectivity for the reduction reaction of carbon dioxide, thereby improving the yield of carbon compounds produced during discharge. The metal-carbon composite catalyst contains metal nanoparticles on the carbon support in a weight ratio of 1:9 to 9:1, preferably 3:7 to 7:3 by weight, more preferably 4:6 to 6:4 by weight, most Preferably, it may be bound in a weight ratio of 5:5. At this time, if the content of the metal nanoparticles is less than 1 weight ratio relative to the carbon support, the reduction reaction activity of carbon dioxide may be reduced, and thus the yield of the carbon compound may be reduced. Conversely, if the content of the metal nanoparticles exceeds 9 weight ratio, further improved catalytic efficiency cannot be expected, and the selectivity for the reduction reaction of carbon dioxide may be reduced.

The carbon support may be at least one selected from carbon black, Ketjen black, acetylene black, graphite, carbon nanotubes, carbon nanofibers, graphene oxide and reduced graphene oxide. Preferably, the carbon support may be at least one selected from carbon black, ketjen black and acetylene black, and most preferably carbon black.

The metal nanoparticles may have a diameter of 1 to 30 nm, and may be at least one selected from gold, silver, copper, and tin. Preferably, the metal nanoparticles have a diameter of 5 to 12 nm, and may be gold, tin, or a mixture thereof, and most preferably, the metal nanoparticles may be gold having a diameter of 7 to 8 nm.

The aqueous electrolyte is selected from sodium hydrogen carbonate (NaHCO ₃ ), sodium hydroxide (NaOH), sodium sulfate (Na ₂ SO ₄ ), sodium nitrate (NaNO ₃ ), sodium chloride (NaCl) and sodium carbonate (Na ₂ CO ₃ ) There may be more than one type. Preferably, the aqueous electrolyte may be sodium hydrogen carbonate (NaHCO ₃ ), sodium hydroxide (NaOH), or a mixture thereof, and most preferably sodium hydrogen carbonate (NaHCO ₃ ). The sodium bicarbonate (NaHCO ₃ ) is better ionized in water compared to other aqueous electrolytes, thereby improving the reduction reaction with carbon dioxide. The aqueous electrolyte may be dissolved in the water generated in Reaction Formula 2 during charging and present in the positive electrode in an electrolyte state.

Carbon dioxide may be injected into the aqueous electrolyte of the positive electrode to operate the hybrid sodium-carbon dioxide secondary battery. When the hybrid sodium-carbon dioxide secondary battery is charged by the injection of carbon dioxide, a sodiumization reaction as shown in Scheme 1 below occurs in the negative electrode part, and an oxygen evolution reaction (OER) as shown in Scheme 2 below occurs in the positive electrode part. have.

[Scheme 1]

Na ⁺ + e ^- → Na

[Scheme 2]

4OH ^- → O ₂ + 2H ₂ O + 4e ^-

When the hybrid sodium-carbon dioxide secondary battery is discharged, a desodium reaction as shown in Scheme 3 below occurs in the negative electrode part, and at least one carbon dioxide reduction reaction (CO ₂ RR) selected from the following Reaction Formulas 4 to 7 is performed in the anode part. can happen

[Scheme 3]

Na → Na ⁺ + e ^-

[Scheme 4]

CO ₂ + 2H ⁺ + 2e ^- → CO + H ₂ O

[Scheme 5]

CO ₂ + 2H ⁺ + 2e ^- → HCOOH

[Scheme 6]

2CO ₂ + 12H ⁺ + 12e ^- → C ₂ H ₄ + 4H ₂ O

[Scheme 7]

2CO ₂ + 12H ⁺ + 12e ^- → C ₂ H ₅ OH + 3H ₂ O

^{In particular, during discharge, hydrogen cations (H +} ) and bicarbonate (HCO ₃ ⁻ ) may be generated in the anode part through a spontaneous chemical reaction with water generated through Scheme 2 as shown in Scheme 8 below. The generated hydrogen cations (H ⁺ ) may react with carbon dioxide and electrons as shown in Reaction Schemes 4 to 7 to generate a carbon product or water.

In addition, during discharging, some of the hydrogen is generated as shown in Scheme 9 below, but the content of hydrogen generated by charging and discharging in a current range of 1 to 3 mA is extremely low.

[Scheme 8]

H ₂ O(l) + CO ₂ (g) → H ⁺ (aq) + HCO ₃ ^- (aq)

[Scheme 9]

2H ⁺ +(aq) + 2e ^- → H ₂ (g)

As such, one or more carbon compounds selected from carbon monoxide (CO), formic acid (HCOOH), ethylene (C ₂ H ₄ ) and ethanol (C ₂ H _{5 OH) may be produced by the carbon dioxide reduction reaction, preferably} It may be at least one selected from carbon monoxide (CO) or formic acid (HCOOH), and most preferably carbon monoxide (CO).

Table 1 below shows the operation (charge/discharge) mechanism of the hybrid sodium-carbon dioxide secondary battery.

Referring to Table 1, during charging, a sodiumization reaction occurs in the negative electrode portion and an OER reaction occurs in the positive electrode portion, and during discharging, a desodium reaction occurs in the negative electrode portion and a high value-added compound is produced in the positive electrode portion. It shows that a CO ₂ RR reaction that can produce occurs. At this time, when charging, the theoretical voltage is 3.5 V, and when discharging, when the product is carbon monoxide (CO), the theoretical voltage becomes 2.19 V. Also, when the product is formic acid (HCOOH) during discharge, the theoretical voltage becomes 2.1 V.

In particular, although not explicitly described in the following Examples or Comparative Examples, in the hybrid sodium-carbon dioxide secondary battery according to the present invention, the components of the metal-carbon composite catalyst and its mixing ratio, the type of the aqueous electrolyte, and the amount of carbon dioxide A hybrid sodium-carbon dioxide secondary battery prepared under different injection conditions was charged and discharged 300 times.

As a result, unlike other conditions and other numerical ranges, when all of the following conditions were satisfied, the battery life was excellent because the negative electrode or positive electrode did not disappear even after 300 charge/discharge cycles. recovered.

① the metal-carbon composite catalyst is one in which metal nanoparticles are bound on a carbon support in a weight ratio of 4:6 to 6:4, ② the carbon support is at least one selected from carbon black, ketjen black, and acetylene black, ③ The metal nanoparticles have a diameter of 5 to 12 nm, gold, tin, or a mixture thereof, ④ the aqueous electrolyte is sodium hydrogen carbonate (NaHCO ₃ ), sodium hydroxide (NaOH) or a mixture thereof, ⑤ of the positive electrode The hybrid sodium-carbon dioxide secondary battery is operated by injecting carbon dioxide into the aqueous electrolyte, and ⑥ the hybrid sodium-carbon dioxide secondary battery undergoes a sodiumization reaction as shown in the following Reaction Formula 1 in the negative electrode part during charging, and in the positive electrode part An oxygen evolution reaction (OER) as shown in Scheme 2 below occurs,

[Scheme 1]

Na ⁺ + e ^- → Na

[Scheme 2]

4OH ^- → O ₂ + 2H ₂ O + 4e ^-

⑦ When the hybrid sodium-carbon dioxide secondary battery is discharged, a desodium reaction as shown in Scheme 3 below occurs in the negative electrode part, and at least one carbon dioxide reduction reaction selected from the following Reaction Formula 4 or Scheme 5 in the positive electrode part (CO ₂ RR) this is happening,

[Scheme 3]

Na → Na ⁺ + e ^-

[Scheme 4]

CO ₂ + 2H ⁺ + 2e ^- → CO + H ₂ O

[Scheme 5]

CO ₂ + 2H ⁺ + 2e ^- → HCOOH

⑧ One or more carbon compounds selected from carbon monoxide (CO) or formic acid (HCOOH) may be produced by the carbon dioxide reduction reaction.

However, if any one of the above eight conditions is not satisfied, the lifespan of the battery is reduced due to a decrease in the charging and discharging efficiency, and the carbon compound due to the carbon dioxide reduction reaction during discharge is not properly generated or the reaction does not occur sufficiently. The content of the carbon compound was very small.

In particular, although not explicitly described in the following Examples or Comparative Examples, in the hybrid sodium-carbon dioxide secondary battery according to the present invention, a hybrid sodium-carbon dioxide secondary battery satisfying all of the following more preferable conditions was prepared and 200 at room temperature Charging and discharging was carried out for a period of time.

As a result, unlike in other conditions and in other numerical ranges, when all of the following conditions were satisfied, the amount of electrical energy generated remarkably increased and the amount of carbon compound production of carbon dioxide also increased.

① The metal-carbon composite catalyst is a carbon support in which metal nanoparticles are bound in a 5:5 weight ratio, ② the carbon support is carbon black, ③ the metal nanoparticles are gold having a diameter of 7-8 nm, ④ The aqueous electrolyte is sodium hydrogen carbonate (NaHCO ₃ ), ⑤ carbon dioxide is injected into the aqueous electrolyte of the positive electrode to operate the hybrid sodium-carbon dioxide secondary battery, ⑥ the hybrid sodium-carbon dioxide secondary battery is a negative electrode part when charging In the reaction formula 1 below, a sodiumization reaction occurs, and in the anode portion, an oxygen evolution reaction (OER) as in Reaction Equation 2 occurs,

[Scheme 1]

Na ⁺ + e ^- → Na

[Scheme 2]

4OH ^- → O ₂ + 2H ₂ O + 4e ^-

⑦ When the hybrid sodium-carbon dioxide secondary battery is discharged, a desodiation reaction as shown in Scheme 3 below occurs in the negative electrode part, and a carbon dioxide reduction reaction (CO ₂ RR) as shown in Scheme 4 below occurs in the anode part,

[Scheme 3]

Na → Na ⁺ + e ^-

[Scheme 4]

CO ₂ + 2H ⁺ + 2e ^- → CO + H ₂ O

⑧ A carbon compound of carbon monoxide (CO) may be produced by the carbon dioxide reduction reaction.

However, when any one of the above eight conditions was not satisfied, the amount of carbon compound production of electric energy and carbon dioxide was low, and the electrode was lost due to long-time charging and discharging, thereby reducing the lifespan of the battery.

On the other hand, the present invention provides a secondary battery composite system including the hybrid sodium-carbon dioxide secondary battery.

a carbon dioxide supply unit for supplying carbon dioxide to the hybrid sodium-carbon dioxide secondary battery; an energy storage system (ESS) for storing electric energy generated from the hybrid sodium-carbon dioxide secondary battery; and a reaction product storage unit for storing a carbon compound of carbon dioxide generated from the hybrid sodium-carbon dioxide secondary battery.

The energy storage system stores electrical energy and, if necessary, serves to supply electrical energy to the hybrid sodium-carbon dioxide secondary battery to efficiently use energy.

The secondary battery complex system may further include a hydrogen storage unit for storing hydrogen generated from the hybrid sodium-carbon dioxide secondary battery and a fuel cell receiving hydrogen from the hydrogen storage unit.

The conventional CO ₂ RR secondary battery system has a structure that can obtain a high value-added product only by consuming electrical energy, but the secondary battery composite system of the present invention provides the electric energy generated by the charging and discharging of the hybrid sodium-carbon dioxide secondary battery. By storing it in an energy storage system, energy can be stored and converted flexibly and used efficiently. In addition, it is possible to obtain various high value-added carbon compounds produced by the reduction reaction of carbon dioxide.

In addition, the present invention is a cathode (anode) portion; anode (cathode) part; and a solid electrolyte positioned between the negative electrode and the positive electrode; in the hybrid sodium-carbon dioxide secondary battery comprising: (a) supplying an aqueous electrolyte to the positive electrode in the method for producing a carbon compound of carbon dioxide step; (b) supplying carbon dioxide to the anode part to which the aqueous electrolyte is supplied; and (c) applying a current between the anode part and the cathode part ^{to form hydrogen ions (H +} ) in the anode part, and the hydrogen ions (H ⁺ ) reduce carbon dioxide to produce a carbon compound of carbon dioxide It provides a method for producing a carbon compound of carbon dioxide containing;

In step (c), a current of 1 to 3 mA, preferably 2 to 3 mA, and most preferably 2.4 to 3 mA may be applied between the anode part and the cathode part. At this time, if the intensity of the current is less than 1 mA, the amount of carbon compound produced may be significantly reduced relative to the amount of hydrogen produced, and if it is greater than 3 mA, deterioration of the electrode may occur at the anode or the cathode due to the high current.

The carbon compound of carbon dioxide may be at least one selected from carbon monoxide (CO), formic acid (HCOOH), ethylene (C ₂ H ₄ ) and ethanol (C ₂ H ₅ OH), preferably carbon monoxide (CO) or formic acid (HCOOH) may be at least one selected from, most preferably carbon monoxide (CO).

The carbon compound of carbon dioxide produced in step (c) may be produced with a faradaic efficiency of 55% or more at a current of 1 to 3 mA. Preferably, the carbon compound can be produced with a Faraday efficiency of at least 69% at 2 to 3 mA, and most preferably at least 77% at 2.4 to 3 mA.

As described above, in the hybrid sodium-carbon dioxide secondary battery of the present invention, the negative electrode contains sodium metal and an organic electrolyte, and the positive electrode contains a metal-carbon composite catalyst and an aqueous electrolyte. Value-added carbon compounds and electrical energy can be obtained at the same time. In addition, the hybrid sodium-carbon dioxide secondary battery contains a metal-carbon composite catalyst having excellent activity and selectivity for the reduction reaction of carbon dioxide in the positive electrode, thereby improving the yield of carbon compounds produced during discharge.

In addition, the secondary battery composite system of the present invention includes an energy storage system and the hybrid sodium-carbon dioxide secondary battery, so that various high-value-added carbon compounds and electrical energy can be simultaneously obtained during discharging in one device, and the produced electrical energy is flexible It has the advantage of being able to efficiently use energy by storing and converting it.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by the following examples.

Example 1: Preparation of a hybrid sodium-carbon dioxide secondary battery capable of obtaining a high value-added product of carbon monoxide

(1) Preparation of anode

A coin-type cell was produced under a glove box. After attaching the Na metal to the first current collector, an organic electrolyte was injected. Then, it was sealed with a lid attached with NASICON (solid electrolyte) having a thickness of 1 mm and a diameter of 16 mm.

(2) Preparation of Gold Nanoparticle-Carbon Support Composite Catalyst

To confirm the performance of this system, the synthesized gold nanoparticles were synthesized according to the known literature [Zhu, Wenlei, et al. "Monodisperse Au nanoparticles for selective electrocatalytic reduction of CO ₂ to CO." Journal of the American Chemical Society 135.45 (2013): 16833-16836.].

Then, 200 mg of HAuCl ₄ 3H ₂ O was mixed with 10 ml of tetralin _{to prepare a HAuCl 4} 3H ₂ O solution. In addition, 0.5 mmol of TBAB was mixed with 1 ml of tetralin to prepare a TBAB solution. Then _{, while stirring the HAuCl 4} 3H ₂ O solution with Ar flow in an ice bath, the TBAB solution was added and stirred for 1 hour. Then, Ketjen black was dispersed in 25 ml of hexane, and gold nanoparticles were added in a 1:1 weight ratio, followed by sonication. Then, after blowing hexane, heat treatment was performed in a box furnace at 180° C. for 8 hours to prepare a gold nanoparticle-carbon support composite catalyst in which gold nanoparticles (7-8 nm) were bound on a carbon support. did.

(3) Manufacturing of cathode

The catalyst slurry was mixed with 10 mg of the gold nanoparticle-carbon support composite catalyst, 45 μl of 5% Nafion, and 1 ml of IPA, followed by ultrasonication for 30 minutes. The second current collector is a carbon paper (carbon paper, Toray TGP-H -060) (0.25 cm 2) of the catalyst slurry on the drop-casting (drop casting) (1 mg / cm 2) and dried overnight (overnight) .

(4) Hybrid sodium-carbon dioxide secondary battery manufacturing

The negative electrode and the positive electrode were bonded with a NASICON (solid electrolyte) interposed therebetween to prepare a hybrid sodium-carbon dioxide secondary battery.

Example 2: Preparation of hybrid sodium-carbon dioxide secondary battery capable of obtaining high value-added products of carbon monoxide and formic acid

A hybrid sodium-carbon dioxide secondary battery was prepared in the same manner as in Example 1, except that tin (Sn) nanoparticles having a diameter of 7 to 8 nm were used instead of gold (Au) nanoparticles as a metal catalyst material during the preparation of the positive electrode. .

Experimental Example 1: Evaluation of charging and discharging of the hybrid sodium-carbon dioxide secondary battery prepared in Example 1

Charging and discharging performance was evaluated using the hybrid sodium-carbon dioxide secondary battery prepared in Example 1, and the results are shown in FIGS. 2 to 5 .

After injecting 8 ml _{of an aqueous electrolyte (0.5 M NaHCO 3} ) into the positive electrode of the hybrid sodium-carbon dioxide secondary battery prepared in Example 1, _{CO 2} gas flow was injected at 10 ml/min. The performance of the secondary battery was measured at room temperature using a battery cycler (WBCS3000, WonAtech), and the Faradic Efficiency (FE) is a Gas Chromatograph composed of FID and TCD in the case _{of gas products (eg, H 2 , CO).} (GC) was determined using (Agilent 7890B). Also, in the case of a liquid product (eg, HCOOH), FE was measured using a liquid chromatography (LC) (YL9100). FE was obtained through Equation 1 as follows.

[Equation 1]

In Equation 1, N is the number of electrons required to convert _{CO 2 to x, α x} is a conversion factor obtained by GC calibration, F is Faraday constant, I is total current, and R is gas constant.

FIG. 2 is a transmission electron microscope (TEM) image of the gold nanoparticle-carbon support composite catalyst prepared in Example 1. FIG. Referring to FIG. 2 , it was confirmed that gold nanoparticles having a diameter of 7 to 8 nm were uniformly bound on the carbon support, Ketjen Black.

3 is a graph showing the Faradaic Efficiency _{of carbon monoxide (CO) and hydrogen (H 2} ) generated by current for the hybrid sodium-carbon dioxide secondary battery prepared in Example 1; _{Referring to FIG. 3, ferdaic efficiencies (FEs) of CO and H 2} at currents of 0.5, 1, 1.5, 2, 2.25, 2.4, and 2.9 mA, respectively, are shown in Table 2 below.

According to the results of Table 2, as the intensity of the current increased, the Faraday efficiency of carbon monoxide (CO) increased, and thus it was confirmed that the Faraday efficiency _{of hydrogen (H 2 ) was relatively decreased.} In particular, it was confirmed that carbon monoxide (CO) had a Faraday efficiency of 79% or more when the current strength was 2.4 and 2.9 mA.

4 is a graph showing the discharge and charge voltage profiles of the hybrid sodium-carbon dioxide secondary battery prepared in Example 1. FIG. Referring to FIG. 4 , when the charging/discharging voltage profile for each current was viewed, the voltage during discharge at 0.5 mA was about 2 V, and the voltage during charging was about 4 V. At 1.5 mA, the discharge voltage was about 1.5 V and the charge voltage was about 4.5 V. At 2 mA, the discharge voltage was about 1 V and the charge voltage was 4.8 V. Through this, it was confirmed that the hybrid sodium-carbon dioxide secondary battery can be operated as an efficient secondary battery composite system by stably realizing a voltage of 1V or more during charging and discharging.

5 is a graph showing a galvanostatic discharge-charge cycling curve at a current of 1 mA for the hybrid sodium-carbon dioxide secondary battery prepared in Example 1; Referring to FIG. 5 , as a result of checking a charge/discharge curve in the galvanostatic mode in order to confirm the cyclability of the hybrid sodium-carbon dioxide secondary battery, it was confirmed that the hybrid battery was stably operated for more than about 30 hours (90 cycles).

Experimental Example 2: Evaluation of charging and discharging of the hybrid sodium-carbon dioxide secondary battery prepared in Example 2

The hybrid sodium-carbon dioxide secondary battery prepared in Example 2 was used for charging and discharging performance evaluation in the same manner as in Experimental Example 1, and the results are shown in FIGS. 6 and 2 .

6 is a graph of the discharge voltage according to the current of the hybrid sodium-carbon dioxide secondary battery prepared in Example 2 (a) and the Faraday efficiency _{of formic acid (HCOOH), carbon monoxide (CO) and hydrogen (H 2 )} Faradaic Efficiency) is a graph (b).

In the case of Table 3 and FIG. 6(a), the discharge voltages were 1.2, 0.9, and 0.4V at the currents of 1, 2, and 3 mA, respectively. In the case of FIG. 6(b), it was confirmed that carbon monoxide (CO) and formic acid (HCOOH) were simultaneously generated at a current of 1, 2, and 3 mA, and the Faraday efficiency of each product also increased as the intensity of the current increased. Through this, it was confirmed that carbon monoxide (CO) as well as formic acid (HCOOH) were simultaneously produced by using tin nanoparticles with a diameter of 7 to 8 nm as metal nanoparticles in the metal-carbon composite catalyst.

Claims (17)

a first current collector, an anode portion containing sodium metal and an organic electrolyte;
a second current collector, a metal-carbon composite catalyst, and a cathode containing an aqueous electrolyte; and
a solid electrolyte positioned between the negative electrode and the positive electrode;
including,
The metal-carbon composite catalyst is one in which metal nanoparticles are bound in a weight ratio of 5:5 on a carbon support,
The carbon support is carbon black,
The metal nanoparticles are gold having a diameter of 7 to 8 nm,
The aqueous electrolyte is sodium hydrogen carbonate (NaHCO ₃ ),
By injecting carbon dioxide into the aqueous electrolyte of the positive electrode, the hybrid sodium-carbon dioxide secondary battery is operated,
The hybrid sodium-carbon dioxide secondary battery undergoes a sodiumization reaction as shown in Scheme 1 below in the negative electrode part during charging,
[Scheme 1]
Na ⁺ + e ^- → Na
At the anode part, an oxygen evolution reaction (OER) as shown in Reaction Formula 2 below occurs,
[Scheme 2]
4OH ^- → O ₂ + 2H ₂ O + 4e ^-
The hybrid sodium-carbon dioxide secondary battery undergoes a desodium reaction as shown in Reaction Equation 3 below in the negative electrode portion during discharging,
[Scheme 3]
Na → Na ⁺ + e ^-
At the anode part, a carbon dioxide reduction reaction (CO ₂ RR) as shown in the following Reaction Formula 4 occurs,
[Scheme 4]
CO ₂ + 2H ⁺ + 2e ^- → CO + H ₂ O
Hybrid sodium-carbon dioxide secondary battery, characterized in that a carbon compound of carbon monoxide (CO) is generated by the carbon dioxide reduction reaction.
delete delete delete delete delete delete delete delete delete delete The hybrid sodium-carbon dioxide of claim 1 secondary battery composite system comprising a secondary battery.
13. The method of claim 12,
a carbon dioxide supply unit for supplying carbon dioxide to the hybrid sodium-carbon dioxide secondary battery;
an energy storage system (ESS) for storing electric energy generated from the hybrid sodium-carbon dioxide secondary battery; and
a reaction product storage unit for storing a carbon compound of carbon dioxide generated from the hybrid sodium-carbon dioxide secondary battery;
Secondary battery composite system, characterized in that it further comprises.
anode (anode) part; anode (cathode) part; and a solid electrolyte positioned between the negative electrode part and the positive electrode part; in the hybrid sodium-carbon dioxide secondary battery of claim 1 , in a method for producing a carbon compound of carbon dioxide,
(a) supplying an aqueous electrolyte to the anode part;
(b) supplying carbon dioxide to the anode part to which the aqueous electrolyte is supplied; and
(c) applying a current between the anode part and the cathode part ^{to form hydrogen ions (H +} ) in the anode part, and the hydrogen ions (H ⁺ ) reduce carbon dioxide to produce a carbon compound of carbon dioxide;
A method for producing a carbon compound of carbon dioxide comprising a.
15. The method of claim 14,
In step (c), a method for producing a carbon compound of carbon dioxide, characterized in that applying a current of 1 to 3 mA between the anode and the cathode.
delete 15. The method of claim 14,
The method for producing a carbon compound of carbon dioxide, characterized in that the carbon compound of carbon dioxide produced in step (c) is generated with a faradaic efficiency of 55% or more at a current of 1 to 3 mA.

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