Production of low-cost copper (II) hydroxide electrodes functionalised by high-energy x-rays

Abstract

The invention relates to the development of low-cost functionalised copper (II) hydroxide (f-Cu(OH)2) electrodes for energy storage technologies and electrochemical devices. By means of surface functionalisation using high-energy X-rays, the energy storage capacity of the material is increased and an environmentally friendly production process is provided. The electrodes produced by this method can be used in applications such as supercapacitors, portable electronic devices, and renewable energy systems.

Description

[0001] PRODUCTION OF LOW-COST COPPER (II) HYDROXIDE ELECTRODES FUNCTIONALISED BY HIGH-ENERGY X-RAYS

[0002] Technical Field of the Invention

[0003] The invention relates to a production method for low-cost, high-performance electrode materials for energy storage technologies and electrochemical devices. In the invention, the energy storage capacity of the material is increased by functionalising the surface of copper (II) hydroxide (f-Cu(OH)2) using high-energy X-rays. Owing to the innovative surface modification method, an environmentally friendly and economically advantageous production process is provided. The developed material is suitable for use in supercapacitors, portable electronic devices, and renewable energy systems.

[0004] State of the Art

[0005] Energy storage technologies play an increasingly important role in providing sustainable solutions to the growing global energy demand. Among these technologies, supercapacitors offer significant advantages over conventional batteries in terms of high power density, rapid charge-discharge cycles, and long service life. One of the most critical components determining the performance of supercapacitors is the electrode material employed. The chemical, physical, and surface properties of electrode materials directly affect energy storage capacity and overall device efficiency. In the existing literature, various materials such as carbon derivatives (graphene, carbon nanotubes), metal oxides (MnO2, RuO2), and conductive polymers are used as supercapacitor electrode materials. Although each of these materials provides certain advantages in enhancing energy storage capacity, they also entail specific disadvantages. For example, carbon-based materials such as graphene and carbon nanotubes offer high surface area and conductivity; however, their commercial applicability is limited due to complex production processes and high costs.Metal oxide-based materials provide high specific capacitance values; however, they generally suffer from low cycling stability and brittle structures, resulting in performance degradation during long-term use. In particular, although metal oxides such as MnO2and RUO2exhibit high energy density, their costly production processes and environmental sustainability concerns constitute significant limitations. In addition, although conductive polymers are low-cost and flexible, they suffer from reduced mechanical durability and chemical stability overtime.

[0006] Copper (II) hydroxide (Cu(OH)2)-based materials have also been investigated in energy storage technologies; however, their use as supercapacitor electrodes on their own has remained limited. In the literature, modification methods such as electrodeposition, hydrothermal synthesis, and thermal treatment have been employed to enhance the energy storage capacity of Cu(OH)2. Nevertheless, these methods generally involve high costs, low scalability, and complex production processes. Furthermore, the energy storage performance achieved using conventional modification methods is generally not satisfactory.

[0007] Due to the limitations and inadequacies of existing solutions, including high production costs, low scalability, complex production processes, and low energy storage performance of Cu(OH)2electrode production methods, it has become necessary to develop an improved production method in the field of electrode materials.

[0008] Summary and Aims of the Invention

[0009] The invention described herein relates to an innovative production method involving the manufacture of functionalised copper (II) hydroxide (f-Cu(OH)2) surfaces using high-energy X-rays.

[0010] One aim of the invention is to obtain a Cu(OH)2-based electrode with increased energy storage capacity. Through surface functionalisation by high-energy X-rays, the surface morphology of the material is improved and the formation of redox-active regions is promoted. By this method, the specific capacitance value of the electrodes is significantly increased compared to standard Cu(OH)2electrodes. This enables more efficient performance in energy storage applications such as supercapacitors.Another aim of the invention is to obtain a Cu(OH)2-based electrode having a low-cost and environmentally friendly production method. The use of high-energy X-rays does not require complex chemical processes or conditions such as high temperature or pressure, unlike conventional surface functionalisation methods. These features provide major advantages in terms of suitability for industrial-scale production and sustainability.

[0011] A further aim of the invention is to obtain a Cu(OH)2-based electrode having high electrochemical stability and enabling long service life of energy storage devices. The high-energy X-ray functionalisation method optimises ion transfer mechanisms and increases cycling stability. This renders the material more suitable for industrial and daily use.

[0012] Description of the Figures

[0013] Figure 1. CV voltammograms of the f-Cu(OH)2electrode material obtained at different scan rates.

[0014] Figure 2. GCD curves of the f-Cu(OH)2electrode material obtained at different current densities.

[0015] Figure 3. Nyquist curve of the f-Cu(OH)2electrode material.

[0016] Detailed Description of the Invention

[0017] The invention relates to a production method for electrodes functionalised from copper (II) hydroxide (f-Cu(OH)2) using high-energy X-rays. The method promotes the formation of new isotopes and redox-active regions, optimises surface morphology, and improves ion transfer mechanisms. The production method that is the subject of the invention comprises the process steps of:

[0018] a. placing 1.0-2.0 mg of copper (II) hydroxide (Cu(OH)2) powder into a petri dish by spreading it to obtain a thin and homogeneous layer,

[0019] b. exposing the prepared Cu(OH)2powder to high-energy X-rays having an energy of 10-18 MV at a distance of 100-150 cm from the radiation source, at a dose rate of 600-1000 MU / rnin, with a total dose of 10-20 Gy,c. mixing the functionalised Cu(OH)2(f-Cu(OH)2) obtained after irradiation with carbon black (CB) and polyvinylidene fluoride (PVDF), and

[0020] d. pressing the mixture under a pressure of 10,000-15,000 psi to obtain a monolithic electrode in pellet form.

[0021] Additionally, in one embodiment of the invention, the method comprises the process steps of:

[0022] a. placing 2.0 mg of copper (II) hydroxide (Cu(OH)2) powder into a petri dish by spreading it to obtain a thin and homogeneous layer,

[0023] b. exposing the prepared Cu(OH)2powder to high-energy X-rays having an energy of 15 MV at a distance of 100 cm from the radiation source, at a dose rate of 1000 MU / rnin, with a total dose of 10-20 Gy,

[0024] c. mixing the functionalised Cu(OH)2(f-Cu(OH)2) obtained after irradiation with carbon black (CB) and polyvinylidene fluoride (PVDF) at a mass ratio of 5:3:1, and

[0025] d. pressing the mixture under a pressure of 15,000 psi to obtain a monolithic electrode in pellet form.

[0026] The electrochemical analyses applied in the invention are carried out using a potentiostat / galvanostat in a typical three-electrode electrochemical cell. The f-CU(OH)2monolithic electrode is used as the working electrode, a saturated calomel electrode is used as the reference electrode, and a platinum wire is used as the counter electrode. A TO M Na2SO4solution is used as the electrolyte, and the cell temperature is maintained at ambient conditions. Cyclic voltammetry (CV) analyses are performed in a voltage range of 0-0.8 V at scan rates of 1-100 mV / s in order to examine the redox properties and electrochemical activity of f-Cu(OH)2. Galvanostatic chargedischarge (GCD) analyses are carried out at different constant current densities of 0.1 -0.5 mA / cm2Electrochemical impedance spectroscopy (EIS) measurements are conducted in a frequency range of 0.1- 105Hz to determine ion transfer rate and electrical resistance.

[0027] Figure 1 presents CV voltammograms obtained at different scan rates. The highest specific capacitance value is calculated as 40.3 mF / cm2at a scan rate of 1 mV s’1. At low scan rates, the curves exhibit a broader and more symmetrical structure, indicating high electrochemical activity in the redox-active regions of the material. Thissymmetrical structure indicates that the material exhibits both electric double-layer capacitance (EDLC) and pseudocapacitive behaviour. As the scan rate increases, for example to 100 mV s’1, a decrease in the enclosed area of the curves is observed, which is attributed to insufficient time for ions to reach the electrode surface and for redox reactions to occur. This reflects kinetic limitations of redox reactions and diffusion effects in ion transfer mechanisms. The results demonstrate that f-Cu(OH)2possesses high energy storage capacity at low scan rates and that surface modification is effectively achieved. The regular and reproducible curve shapes confirm the electrochemical stability of the electrode material and its suitability for energy storage applications.

[0028] Galvanostatic charge-discharge (GCD) analysis reveals the energy storage performance of the material at different current densities. The GCD curves shown in Figure 2 exhibit longer durations at low current densities, such as 0.1 mA cm'2, indicating high energy storage capacity and effective contribution of redox-active regions. As the current density increases, for example to 0.5 mA cm-2, a noticeable decrease in charge and discharge times is observed, indicating kinetic limitations in ion transfer and reduced energy storage capacity under these conditions. The GCD curves generally exhibit a smooth and symmetrical structure, demonstrating high electrochemical stability and efficient ion transfer mechanisms. The calculated specific capacitance values are 17.9 mF cm'2at a current density of 0.1 mA cm-2and 6.0 mF cm-2at a current density of 0.5 mA cm-2. These results confirm that f-Cu(OH)2provides high energy storage capacity at low current densities and maintains stable performance at higher current densities.

[0029] Electrochemical impedance spectroscopy (EIS) results evaluated using the Nyquist diagram shown in Figure 3 reveal the electrical conductivity properties and ion transfer resistance of the material. The near-horizontal line in the high-frequency region represents the series resistance (Rs) at the electrode-electrolyte interface. The calculated Rs value for f-Cu(OH)2is 19.2 Q, indicating high electrical conductivity and good contact with the electrolyte. This result demonstrates that surface modification optimises the electrode-electrolyte interface and enables effective ion transfer.

[0030] The semicircle observed in the medium-frequency region represents the charge transfer resistance (Ret) and double-layer capacitance (Cdl). The Ret value of 116.1 Odetermined for f-Cu(OH)2indicates that redox reactions on the surface are kinetically supported and that surface modification effectively increases redox -active regions. The size of the semicircle reflects the charge transfer rate and electrochemical reactivity occurring on the material surface, confirming suitable performance for energy storage applications. The slope in the low-frequency region represents ion diffusion mechanisms known as Warburg impedance. The slope in this region indicates that ions effectively diffuse within the porous structure of f-Cu(OH)2and significantly contribute to the energy storage capacity of the material. The regular structure demonstrating ion transport to the electrode surface and within the porous structures confirms an important feature supporting the energy storage performance of the modified material. Overall, the Nyquist curve demonstrates that f-Cu(OH)2exhibits low internal resistance, high surface reaction kinetics, and effective ion diffusion. The low Rs value confirms good electrical conductivity, the suitable Ret value demonstrates support of redox reactions by surface modification, and the regular Warburg region confirms efficient ion transfer mechanisms. These results confirm that f-Cu(OH)2can be used as an effective supercapacitor electrode with stable performance.

Claims

CLAIMS1. A method for producing electrodes of copper (II) hydroxide functionalised using high-energy X-rays (f-Cu(OH)2), comprising the process steps of:a. placing 1.0-2.0 mg of copper (II) hydroxide (Cu(OH)2) powder into a petri dish by spreading it to obtain a thin and homogeneous layer,b. exposing the prepared Cu(OH)2powder to high-energy X-rays having an energy of 10-18 MV at a distance of 100-150 cm from the radiation source, at a dose rate of 600-1000 MU / rnin, with a total dose of 10-20 Gy, c. mixing the functionalised Cu(OH)2(f-Cu(OH)2) obtained after irradiation with carbon black (CB) and polyvinylidene fluoride (PVDF), andd. pressing the mixture under a pressure of 10,000-15,000 psi to obtain a monolithic electrode in pellet form.

2. The method for producing functionalised copper (II) hydroxide (f-Cu(OH)2) electrodes according to claim 1 , comprising the process steps of:a. placing 2.0 mg of copper (II) hydroxide (Cu(OH)2) powder into a petri dish by spreading it to obtain a thin and homogeneous layer,b. exposing the prepared Cu(OH)2powder to high-energy X-rays having an energy of 15 MV at a distance of 100 cm from the radiation source, at a dose rate of 1000 MU / rnin, with a total dose of 10-20 Gy,c. mixing the functionalised Cu(OH)2(f-Cu(OH)2) obtained after irradiation with carbon black (CB) and polyvinylidene fluoride (PVDF) at a mass ratio of 5:3:1 , andd. pressing the mixture under a pressure of 15,000 psi to obtain a monolithic electrode in pellet form.

Images