A system for the production of agglomerated cadmium sulfide (CdS) nanospheres for applications in supercapacitor electrodes

Abstract

A system for producing agglomerated cadmium sulfide (CdS) nanospheres for supercapacitor electrode applications, comprising: a) a precursor production unit configured to maintain aqueous solutions of cadmium chloride monohydrate (CdCl2.H2O) and sodium sulfide (Na2S) at a concentration of 0.5 M; b) a reaction unit configured to combine the cadmium and sulfide precursors and maintain the reaction conditions at 80 °C to precipitate CdS nanospheres, the reaction unit comprising a temperature controller configured to maintain the temperature of the reaction unit; c) a stirring unit with a gear motor configured to continuously stir the reaction unit at 1050-1100 rpm to ensure uniform growth of the agglomerated nanospheres; d) a purification unit connected to the reaction unit and designed to receive, filter and wash precipitated CdS nanospheres with a filter component based on alcohol and double distilled water; (e) a heat treatment unit connected to the purification unit and configured to dry the CdS precipitate at 60 °C and anneal it at 450 °C to form pure cadmium sulfide; and f) an electrode preparation unit configured to deposit the CdS nanospheres on nickel foam substrates for electrochemical applications.

Description

FIELD OF THE INVENTION

[0001] The present disclosure relates to a system for preparing agglomerated cadmium sulfide (CdS) nanospheres for supercapacitor electrode applications. More specifically, the system is configured to synthesize CdS thin films with agglomerated, nanosphere-like morphologies using three different concentrations of cadmium salt precursors (0.1 M CdCl 2 ·H 2 O (CdS-1), 0.3 M CdCl 2 ·H 2 O (CdS-2), and 0.5 M CdCl 2 ·H 2 O (CdS-3)) while maintaining the 0.5 M Na 2 S precursor. BACKGROUND OF THE INVENTION

[0002] Energy storage systems are becoming increasingly important due to the rapid depletion of fossil fuels and growing environmental concerns. Supercapacitors represent a promising solution, offering high power density, longer lifetimes, short charging times, and excellent reversibility compared to conventional energy storage technologies.

[0003] CdS nanoparticles have proven themselves due to their theoretical capacity of 1675 F g -1 They have proven to be attractive electrode materials for supercapacitor applications due to their good electrical conductivity, redox reversibility, and environmental stability. As an n-type II-VI semiconductor, CdS in nanoparticle form has a band gap of 3.57 eV and exhibits size-dependent properties that make it suitable for electrochemical energy storage applications.

[0004] Existing synthesis systems have achieved varying degrees of success in the fabrication of CdS-based supercapacitor electrodes. State-of-the-art systems reported specific capacitances of 181 F g -1 up to 2100 F g -1 , depending on the synthesis approach and the structural configurations used. However, conventional synthesis systems face limitations in optimizing precursor concentrations to achieve maximum surface area and electrochemical performance.

[0005] Coprecipitation synthesis systems offer advantages in terms of simplicity, cost-effectiveness, and scalability for CdS nanosphere production. However, existing coprecipitation systems lack systematic optimization of cadmium precursor concentrations to maximize both surface area and specific capacity performance simultaneously.

[0006] Therefore, there is a need for an improved synthesis system that can systematically prepare agglomerated CdS nanospheres with optimized precursor concentrations to achieve improved surface properties and superior electrochemical performance for supercapacitor electrode applications. Summary of the invention

[0007] The present disclosure relates to a system for producing cadmium sulfide (CdS) agglomerate nanospheres for supercapacitor electrodes. The present invention provides a comprehensive system for producing cadmium sulfide (CdS) agglomerate nanospheres optimized for supercapacitor electrodes. The system utilizes a coprecipitation process with systematically varied cadmium precursor concentrations to achieve improved surface properties and superior electrochemical performance. The system includes integrated units for precursor preparation, controlled reaction conditions, purification, heat treatment, and electrode preparation, thus enabling consistent production of CdS nanospheres with specific capacitance values ​​in the range of 192 to 911 F g. -1 .

[0008] The present disclosure aims to provide a system for producing cadmium sulfide (CdS) nanospheres for supercapacitor electrodes. The system comprises: a precursor preparation unit configured to maintain aqueous solutions of cadmium chloride monohydrate (CdCl2.H2O) and sodium sulfide (Na2S) at a concentration of 0.5 M; a reaction unit configured to combine the cadmium and sulfide precursors and maintain reaction conditions at 80°C to precipitate CdS nanospheres, wherein the reaction unit comprises a temperature controller configured to maintain the temperature of the reaction unit; a stirring unit with a geared motor configured to continuously move the reaction unit at 1050-1100 rpm to ensure uniform growth of the agglomerated nanospheres;a purification unit connected to the reaction unit and configured to receive precipitated CdS and subsequently filter and wash the nanospheres using a filter component that uses alcohol and double-distilled water; a heat treatment unit connected to the purification unit and configured to dry the CdS precipitate at 60 °C and anneal it at 450 °C to form pure cadmium sulfide; and an electrode preparation unit configured to deposit the CdS nanospheres on nickel foam substrates for electrochemical applications.

[0009] An object of the present disclosure is to provide agglomerated cadmium sulfide (CdS) nanospheres for supercapacitor electrode applications.

[0010] Another objective of the present disclosure is to utilize varying cadmium precursor concentrations while maintaining constant sodium sulfide concentrations to achieve maximum electrochemical performance in the resulting CdS nanosphere electrodes.

[0011] Another object of the present disclosure is to provide an integrated synthesis system capable of producing agglomerated CdS nanospheres with optimized surface properties and improved specific capacitance performance for supercapacitor electrode applications.

[0012] Another object of the present disclosure is to provide a system configured for characterizing the prepared CdS thin films with agglomerated nanosphere-like morphologies.

[0013] To further clarify the advantages and features of the present disclosure, the invention will be explained in more detail with reference to specific embodiments illustrated in the accompanying drawings. These drawings show only typical embodiments of the invention and are therefore not to be construed as limiting its scope. The invention will be described and explained in more detail with reference to the accompanying drawings. SHORT DESCRIPTION OF THE FIGURE

[0014] These and other features, aspects, and advantages of the present disclosure will be better understood when the following detailed description is read with reference to the accompanying drawings, in which like characters represent like parts throughout. Fig. 1 shows a block diagram of a system for producing agglomerated cadmium sulfide (CdS) nanospheres for supercapacitor electrode applications according to an embodiment of the present disclosure.

[0015] Those skilled in the art will also appreciate that the elements in the drawings are shown for convenience and are not necessarily to scale. For example, the flowcharts illustrate the method by key steps to enhance understanding of aspects of the present disclosure. Moreover, with respect to device construction, one or more components of the device may be represented in the drawings by conventional symbols, and the drawing may show only the specific details relevant to understanding embodiments of the present disclosure in order not to clutter the drawings with details that would be readily apparent to those skilled in the art after reading the present description. DETAILED DESCRIPTION:

[0016] For a better understanding of the principles of the invention, reference is made below to the embodiment illustrated in the drawings and described in specific language. However, the scope of the invention is not limited thereby. Changes and further modifications to the illustrated system, as well as further applications of the principles of the invention, are possible, as would normally occur to one skilled in the art to which the invention pertains.

[0017] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be limiting thereof.

[0018] References in this specification to "one aspect," "another aspect," or similar expressions mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Therefore, the occurrences of the terms "in one embodiment," "in another embodiment," and similar expressions throughout this specification may or may not all refer to the same embodiment.

[0019] The terms "comprises," "having," or other variations thereof are intended to cover non-exclusive inclusion, such that a process or method comprising a list of steps not only includes those steps, but may also include other steps not expressly listed or inherent in such process or method. Likewise, the statement "comprises" with respect to one or more devices, subsystems, elements, structures, or components does not exclude, without further limitation, the existence of other devices, other subsystems, elements, structures, or components, or additional devices, additional subsystems, additional elements, additional structures, or additional components.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. The system, methods, and examples provided herein are for illustrative purposes only and should not be considered limiting.

[0021] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0022] Fig. 1 shows a block diagram of a system (100) for producing agglomerated cadmium sulfide (CdS) nanospheres for supercapacitor electrode applications according to an embodiment of the present disclosure.

[0023] Referring to Fig.1, the system (100) comprises: a) a precursor preparation unit (102) configured to maintain aqueous solutions of cadmium chloride monohydrate (CdCl2.H2O) and sodium sulfide (Na2S) at a concentration of 0.5 M; b) a reaction unit (104) configured to combine the cadmium and sulfide precursors and maintain reaction conditions at 80°C to precipitate CdS nanospheres, the reaction unit comprising a temperature controller configured to maintain the temperature of the reaction unit; c) a stirring unit (106) comprising a gear motor and configured to continuously stir the reaction unit at 1050-1100 rpm to ensure uniform growth of the agglomerated nanospheres;d) a purification unit (108) connected to the reaction unit and configured to receive precipitated CdS, filter, and wash nanospheres using a filter component that uses alcohol and double-distilled water; e) a heat treatment unit (110) connected to the purification unit and configured to dry the CdS precipitate at 60°C and anneal it at 450°C to form pure cadmium sulfide; and f) an electrode preparation unit (112) configured to deposit the CdS nanospheres on nickel foam substrates for electrochemical applications.

[0024] In one embodiment, the precursor preparation unit (102) is configured to enable the preparation of cadmium chloride monohydrate precursor solutions in three different concentrations, namely 0.1 M (CdS-1), 0.3 M (CdS-2) and 0.5 M (CdS-3), while maintaining a constant concentration of the sodium sulfide precursor of 0.5 M.

[0025] In one embodiment, the reaction unit (104) is configured to maintain the reaction temperature between 75 and 85 °C for three hours to ensure complete precipitation and formation of yellow colored CdS nanospheres.

[0026] In one embodiment, the stirring unit (106) is configured to stir continuously for three hours after the start of precipitation to ensure uniform growth of the agglomerated nanospheres and complete reaction.

[0027] In one embodiment, the purification unit (108) is configured to perform five to six filtration and washing cycles to remove physically adsorbed and loosely bound particles from the CdS nanospheres.

[0028] In one embodiment, the heat treatment unit (110) is configured to dry overnight at 60°C and then anneal at 450°C for three hours to form a pure cadmium sulfide phase.

[0029] In one embodiment, the electrode preparation unit (112) is configured to deposit CdS nanospheres onto pre-cleaned nickel foam substrates that have been dried in hot air for 30 minutes.

[0030] In one embodiment, the system (100) further comprises a characterization unit (114) configured to analyze the CdS nanospheres, the characterization unit (114) comprising: an X-ray diffractometer equipment for analyzing the crystal phase structure; a Fourier transform infrared spectrometer for material characterization; a field emission scanning electron microscope for analyzing the surface morphology; and a BET surface area analyzer for determining surface area and pore size.

[0031] In one embodiment, the system (100) further comprises an electrochemical test unit (116) configured to evaluate the supercapacitive performance of the CdS nickel foam electrodes, wherein the electrochemical test unit (116) comprises: cyclic voltammetry equipment for analyzing capacitive behavior; galvanostatic charge / discharge equipment for measuring specific capacitances; and electrochemical impedance spectroscopy equipment for electrode characterization.

[0032] In one embodiment, the system is configured to produce agglomerated CdS nanospheres with specific capacitance values ​​in the range of 192 Fg -1 up to 911 Fg -1 and surfaces in the range of 35.26 m 2 G -1 up to 90.45 m 2 G -1 , depending on the cadmium precursor concentration used.

[0033] The present invention comprises a comprehensive system architecture for the systematic production of cadmium sulfide nanospheres with optimized electrochemical properties for supercapacitor applications. The system integrates several specialized units that work in a coordinated manner to achieve consistent and reproducible synthesis results while maximizing the specific capacitance and surface properties of the resulting CdS nanospheres.

[0034] The precursor preparation unit forms the basis of the system. It maintains precise aqueous solutions of cadmium chloride monohydrate in three different concentration levels, ranging from 0.1 M to 0.5 M, while simultaneously preparing sodium sulfide solutions at a constant concentration of 0.5 M. This systematic variation of the cadmium precursor concentration enables the production of three different CdS variants, each with unique electrochemical and morphological properties.

[0035] The reaction unit provides controlled environmental conditions for optimal CdS nanosphere formation, maintaining a reaction temperature of 80 °C with precise temperature control of ±5 °C throughout a three-hour reaction time. This controlled thermal environment ensures complete precipitation and uniform growth of the agglomerated nanosphere structures while preventing unwanted side reactions or the development of irregular morphology.

[0036] The stirring unit provides continuous mechanical agitation at precisely controlled speeds between 1050 and 1100 rpm for three hours after the start of precipitation. This controlled agitation ensures uniform distribution of the reactants, promotes consistent nucleation and growth patterns, and prevents agglomeration irregularities that could compromise the quality and electrochemical performance of the final nanospheres.

[0037] The purification unit performs critical post-synthesis purification processes through systematic filtration and washing cycles with alcohol and double-distilled water. This purification process removes physically adsorbed impurities and loosely bound particles that could impair electrochemical performance, ensuring the final CdS nanospheres maintain optimal purity levels for supercapacitor applications.

[0038] The heat treatment unit features sophisticated temperature control for two distinct heat treatment phases. The first drying phase runs overnight at 60 °C to remove residual moisture. This is followed by a three-hour high-temperature annealing phase at 450 °C, which promotes the development of the crystal structure and ensures the formation of pure cadmium sulfide with optimal electrochemical properties.

[0039] The electrode preparation unit completes the system by depositing the synthesized CdS nanospheres onto pre-cleaned nickel foam substrates, creating functional supercapacitor electrodes ready for electrochemical evaluation. The system exhibits exceptional performance characteristics: The optimized CdS-2 variant achieves specific capacitance values ​​of 911 F g -1 and surface properties of 90.45 m 2 G -1, thus significantly exceeding other concentration variants and proving the effectiveness of the system in the production of high-performance supercapacitor electrode materials.

[0040] The present invention relates to a system for producing agglomerated cadmium sulfide (CdS) nanospheres based on a coprecipitation-based synthesis protocol. The system comprises a precursor preparation unit. This unit is configured to enable the preparation of three different cadmium precursor solutions. These consist of 50 ml each of 0.1 M (CdS-1), 0.3 M (CdS-2), and 0.5 M (CdS-3) cadmium chloride monohydrate (CdCl2·H2O), each placed in separate 250 ml beakers. An equal volume (50 ml) of a pale yellow 0.5 M aqueous sodium sulfide (Na2S) solution is added to each cadmium precursor solution.

[0041] The system also includes a reaction unit that receives and combines these precursor solutions and maintains the reaction temperature at approximately 80 °C (± 5 °C). During the reaction process, the initially colorless mixture transforms into a yellow precipitate, indicating CdS nanosphere formation. The reaction unit features a temperature controller that ensures thermal stability throughout the three-hour reaction period for complete precipitation. At the same time, the stirring unit with an integrated gear motor ensures continuous stirring at a controlled speed of 1050 to 1100 rpm. Stirring is continued for three hours after the start of precipitation to promote uniform nucleation and growth of agglomerated CdS nanospheres and ensure the completion of the chemical reaction.After the reaction is complete, the resulting precipitate is transferred to the purification unit, which performs sequential filtration and washing of the synthesized CdS nanospheres. The purification process involves five to six washing cycles with alcohol and double-distilled water to remove any physically adsorbed or loosely bound impurities from the particle surface. After purification, the processed material is transferred to the heat treatment unit. This unit is configured to dry the CdS precipitate overnight at 60 °C and then anneal the dried product for three hours at 450 °C. This two-step heat treatment ensures the formation of a pure crystalline phase of cadmium sulfide, corresponding to samples CdS-1, CdS-2, and CdS-3. The electrode preparation unit is used for electrode preparation.Pre-cleaned nickel foam substrates, dried in hot air for 30 minutes, are used as current collectors. The annealed CdS nanospheres from each sample set are deposited onto these nickel foam substrates in preparation for electrochemical analysis. The subsequent evaluation of the synthesized electrodes is carried out using the electrochemical test unit, which measures the supercapacitive behavior of the CdS-nickel foam electrodes using cyclic voltammetry, galvanostatic charge-discharge analysis, and electrochemical impedance spectroscopy to determine parameters such as specific capacitance, charge retention, and impedance properties.

[0042] CdS-1, CdS-2, and CdS-3 nanospheres were characterized. A Bruker D2 Phaser X-ray diffractometer with Cu Kα radiation (λ=1.5418 Å) operating at 10 mA current and 30 kV voltage, and a Perkin Elmer Fourier transform infrared (FTIR) spectrometer (FRONTIER MIR / FIR + SP10 STD) were used to investigate the crystal phase structures of the three materials. Three synthesized samples were subjected to surface morphology analysis using a field emission scanning electron microscope (200 kV). N2 adsorption-desorption isotherm curves were used to investigate surface area and pore size using the Brunauer-Emmett-Teller (BET) method. The JPS 9030 physical electronics instrument was used to analyze the samples using X-ray photoelectron spectroscopy (XPS). A 532 nm solid-state laser was used as the excitation source at room temperature to obtain Raman spectra using a Horiba Jobin Yvon Lab RAM HR spectrometer.A detailed structural investigation was carried out using high-resolution transmission electron microscopy at 200 kV accelerating voltage.

[0043] In one embodiment, the electrochemical test unit (116) is configured to evaluate the supercapacitive performance of CdS-1, CdS-2, and CdS-3 nanospheres deposited on nickel foam substrates. These evaluations are performed using a standard three-electrode electrochemical test setup, with the CdS-Ni foam electrodes serving as the working electrode, a platinum wire as the counter electrode, and a saturated calomel electrode (SCE) as the reference electrode. This testing enables a comprehensive evaluation of the electrochemical behavior and energy storage potential of the CdS-based nanostructured electrodes. The electrolyte medium used for all measurements is 1 M potassium hydroxide (KOH). Electrochemical impedance spectroscopy (EIS), galvanostatic charge / discharge spectroscopy (GCD), and cyclic voltammetry (CV) are performed using a potentiostat (VMP3, Bio-Logic, France).The cyclic voltammetry measurements are performed at scan rates of 5 mV s. -1 up to 100 mV s -1 to evaluate the capacitive behavior of the CdS-Ni foam electrodes. For galvanostatic charge / discharge tests, a range of current densities from 5 A g -1 up to 30 A g -1 applied to determine specific capacitance properties. Electrochemical impedance spectroscopy is performed over a frequency range of 0.01 Hz to 100 kHz with an AC signal amplitude of 5 mV to analyze the electrode resistance and capacitive response. The specific capacitance (Csp) in farads per gram (F g -1 ) is calculated using equation (1): Csp=(I×Δt) / (ΔV×m)

[0044] In the above equation, Csp is the specific capacity (F g -1 ), I is the discharge current (mA cm -2), Δt is the discharge time (s), ΔV is the voltage window (V) and m is the mass of the active CdS material deposited on the nickel foam (g).

[0045] The proposed system is designed for the synthesis of agglomerated cadmium sulfide (CdS) nanospheres. It uses a coprecipitation process in which a constant concentration of sodium sulfide (Na2S) is maintained and the concentrations of the cadmium chloride monohydrate precursor (CdCl2·H2O) are varied to 0.1 M (CdS-1), 0.3 M (CdS-2), and 0.5 M (CdS-3). The formation of uniform nanospheres was attributed to the localized Cd 2+-ion ​​concentration and synergistic interactions during precipitation. Of the three processes, CdS-2 provided the highest yield and exhibited superior morphological and electrochemical properties. X-ray diffraction (XRD) confirmed the crystalline phase of all three samples and showed peaks consistent with JCPDS No. 41-1049. CdS-2 and CdS-3 exhibited sharper peaks, while CdS-1 exhibited peak broadening, indicating a smaller crystallite size due to the lower precursor concentration. FT-IR analysis revealed characteristic bands, including -OH stretching, HOH bending, and Cd-S stretching, with CdS-2 exhibiting more intense and sharper peaks, indicating better structural definition. Field emission scanning electron microscopy (FESEM) showed nanosphere morphologies in all samples, with CdS-2 exhibiting highly interconnected and uniform spheres, supporting the improved performance.Transmission electron microscopy (TEM) of CdS-2 confirmed spherical structures with particle sizes ranging from 4.2 to 5.4 nm, while energy-dispersive X-ray spectroscopy (EDS) confirmed the elemental composition as 44.3% Cd and 55.7% S. Raman spectroscopy showed strong first- and second-order longitudinal optical phonon modes, further confirming the crystalline quality. BET surface area analysis revealed that CdS-2 has a surface area of ​​90.45 m. 2 / g had the largest surface area, compared to 40.23 m 2 / g for CdS-1 and 35.26 m 2 / g for CdS-3. CdS-2 also exhibited a narrow pore radius of ~2.27 nm, indicating its mesoporous nature. X-ray photoelectron spectroscopy (XPS) of CdS-2 revealed the presence of Cd 2+ and S 2-in their expected oxidation states, as well as chemisorbed oxygen, supporting the formation of pure CdS. Electrochemical tests of CdS-1, CdS-2, and CdS-3 nanospheres deposited on nickel foam electrodes were performed using a three-electrode setup in 1 M KOH. Cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) analyses showed that CdS-2 / NF exhibited the highest specific capacitance of 911 F / g at a current density of 5 A / g, significantly outperforming CdS-1 / NF (192 F / g) and CdS-3 / NF (218 F / g). The superior performance of CdS-2 / NF was attributed to its thin layer, high surface area, and strong interconnection between the nanospheres, enabling better electrochemical activity and ion transport. Electrochemical impedance spectroscopy (EIS) confirmed that CdS-2 / NF had the lowest charge transfer resistance (1.13 ohms -1 ) compared to CdS-1 / NF (3.14 Ohm -1 ) and CdS-3 / NF (3.18 Ohm-1 ). Furthermore, CdS-2 / NF retained 94% of its original capacity over 5000 CV cycles, indicating excellent cycling stability. This improved performance is attributed to the compact and well-connected nanosphere morphology of CdS-2, which promotes efficient charge transport and mechanical integrity. Overall, CdS-2 / NF proves to be a promising material for high-performance supercapacitor applications, with structural, morphological, and electrochemical properties that outperform both lower- and higher-concentration variants, as well as many previously reported metal sulfide-based devices.

[0046] The drawing and the above description show examples of embodiments. Those skilled in the art will recognize that one or more of the described elements may well be combined into a single functional element.

[0047] Alternatively, certain elements may be split into multiple functional elements. Elements of one embodiment may be added to another embodiment. For example, the order of the processes described herein may be changed and is not limited to the manner described herein. Furthermore, the actions of a flowchart do not have to be implemented in the order shown; nor do all actions necessarily have to be performed. Also, actions that are not dependent on other actions may be performed in parallel with the other actions. The scope of the embodiments is in no way limited by these specific examples. Numerous variations, whether explicitly stated in the specification or not, such as differences in structure, dimensions, and use of materials, are possible. The scope of the embodiments is at least as broad as set forth in the following claims.

[0048] Advantages, further benefits, and solutions to problems have been described above with reference to specific embodiments. However, the advantages, advantages, solutions to problems, and any components that may result in an advantage, advantage, or solution occurring or becoming more apparent are not to be construed as critical, required, or essential features or components of any or all of the claims. REFERENCES 100 A system for producing agglomerated cadmium sulfide (CdS) nanospheres for applications in supercapacitor electrodes. 102 Precursor processing unit 104 reaction unit 106 agitator 108 cleaning unit 110 Heat treatment unit 112 Electrode preparation unit 114 Characterization unit 116 Electrochemical test unit

Claims

[1] A system for producing agglomerated cadmium sulfide (CdS) nanospheres for supercapacitor electrode applications, comprising: a) a precursor production unit configured to maintain aqueous solutions of cadmium chloride monohydrate (CdCl2.H2O) and sodium sulfide (Na2S) at a concentration of 0.5 M; b) a reaction unit configured to combine the cadmium and sulfide precursors and maintain the reaction conditions at 80 °C to precipitate CdS nanospheres, the reaction unit comprising a temperature controller configured to maintain the temperature of the reaction unit; c) a stirring unit with a gear motor configured to continuously stir the reaction unit at 1050-1100 rpm to ensure uniform growth of the agglomerated nanospheres; d) a purification unit connected to the reaction unit and designed to receive, filter and wash precipitated CdS nanospheres with a filter component based on alcohol and double distilled water; (e) a heat treatment unit connected to the purification unit and configured to dry the CdS precipitate at 60 °C and anneal it at 450 °C to form pure cadmium sulfide; and f) an electrode preparation unit configured to deposit the CdS nanospheres on nickel foam substrates for electrochemical applications. [2] The system of claim 1, wherein the precursor preparation unit is configured to enable the preparation of cadmium chloride monohydrate precursor solutions in three different concentrations, namely 0.1 M (CdS-1), 0.3 M (CdS-2) and 0.5 M (CdS-3), while maintaining a constant concentration of the sodium sulfide precursor of 0.5 M. [3] The system of claim 1, wherein the reaction unit is configured to maintain the reaction temperature between 75 and 85 °C for three hours to ensure complete precipitation and formation of yellow colored CdS nanospheres. [4] The system of claim 1, wherein the stirring unit is configured to allow continuous stirring for three hours after the start of precipitation to ensure uniform growth of the agglomerated nanospheres and complete reaction. [5] The system of claim 1, wherein the purification unit is configured to perform five to six filtration and washing cycles to remove physically adsorbed and loosely bound particles from the CdS nanospheres. [6] The system of claim 1, wherein the heat treatment unit is configured to dry overnight at 60°C and then anneal at 450°C for three hours to achieve a pure cadmium sulfide phase. [7] The system of claim 1, wherein the electrode preparation unit is configured to deposit CdS nanospheres onto pre-cleaned nickel foam substrates that have been dried in hot air for 30 minutes. [8] The system of claim 1, further comprising a characterization unit configured to analyze the CdS nanospheres, the characterization unit comprising: X-ray diffractometer - equipment for analyzing the crystal phase structure; Fourier transform infrared spectrometer for material characterization; field emission scanning electron microscope for analyzing surface morphology; and BET surface area analyzer for determining surface area and pore size. [9] The system of claim 1, further comprising an electrochemical test unit configured to evaluate the supercapacitive performance of the CdS nickel foam electrodes, the electrochemical test unit comprising: cyclic voltammetry equipment for analyzing capacitive behavior; galvanostatic charge / discharge equipment for measuring specific capacitance; and electrochemical impedance spectroscopy equipment for electrode characterization. [10] The system of claim 1, wherein the system is configured to comprise agglomerated CdS nanospheres having specific capacitance values ​​in the range of 192 Fg -1 up to 911 Fg -1 and surfaces in the range of 35.26 m 2 G -1 up to 90.45 m 2 G -1 , depending on the cadmium precursor concentration used.

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