1. We claim that a hierarchically engineered ternary nanocomposite comprising CuFe₂O₄, NiCo₂S₄, and carbon nanotubes (CNTs) is developed for high-performance electrochemical energy storage applications.

2. We claim that the CuFe₂O₄ component acts as a structurally stable ferrite framework providing multiple redox-active sites through reversible Cu²⁺/Cu⁺ and Fe³⁺/Fe²⁺ transitions.

3. We claim that the NiCo₂S₄ component enhances electrical conductivity and electrochemical activity due to its multiple oxidation states and fast charge transfer kinetics.

4. We claim that the carbon nanotubes (CNTs) form a three-dimensional conductive network that facilitates rapid electron transport and improves mechanical strength of the composite.

5. We claim that the hierarchical architecture consists of CuFe₂O₄ nanoparticles uniformly anchored on CNTs with NiCo₂S₄ nanosheets or nanoflakes grown in-situ to form an interconnected porous structure.

6. We claim that the nanocomposite is synthesized through a controlled multi-step process including CNT functionalization, hydrothermal synthesis of CuFe₂O₄, composite formation, and in-situ sulfidation for NiCo₂S₄ growth.

7. We claim that hydrothermal and/or solvothermal methods are employed to achieve uniform morphology, controlled particle size, and strong interfacial interaction among the components.

8. We claim that the resulting nanocomposite electrode exhibits high specific capacitance, superior rate capability, and reduced internal resistance.

9. We claim that the nanocomposite is suitable for use in supercapacitors, hybrid capacitors, and other electrochemical energy storage devices.

10. We claim that the synergistic interaction among CuFe₂O₄, NiCo₂S₄, and CNTs significantly enhances cycling stability, energy density, and power density compared to conventional electrode materials.

Description:Preamble
The rapid advancement of modern technology and the growing global demand for efficient energy management systems have intensified the need for advanced energy storage devices with superior performance characteristics. In recent years, electrochemical energy storage systems, particularly supercapacitors and hybrid capacitors, have gained significant attention due to their high power density, fast charge–discharge capability, and long operational lifespan. However, the development of high-performance electrode materials remains a critical challenge, as conventional materials often suffer from limited electrical conductivity, insufficient electrochemical activity, and poor cycling stability.
Supercapacitors, though advantageous in terms of power delivery, are often constrained by relatively low energy density compared to batteries. This limitation arises primarily from the inherent properties of traditional electrode materials, which either rely on electrical double-layer capacitance or exhibit limited pseudocapacitive behavior. Therefore, there exists a compelling need to design and develop novel electrode materials that can effectively combine high energy density with high power density while maintaining long-term stability.
In this context, nanostructured materials have emerged as promising candidates due to their high surface area, tunable morphology, and enhanced electrochemical properties. Among them, transition metal oxides, sulfides, and carbon-based materials have been extensively explored for their potential in energy storage applications. However, individual materials often fail to deliver optimal performance due to inherent drawbacks such as poor conductivity in metal oxides or structural instability during repeated cycling.
To overcome these limitations, the concept of hybrid and ternary nanocomposites has been introduced, wherein multiple materials are strategically integrated to exploit their complementary properties. Such composites enable synergistic interactions that significantly enhance charge storage capability, conductivity, and structural integrity. Particularly, the integration of ferrite materials, metal sulfides, and conductive carbon frameworks has shown considerable promise in achieving superior electrochemical performance.
Copper ferrite (CuFe₂O₄) is a spinel ferrite material known for its structural stability and multiple oxidation states, which contribute to redox-based charge storage mechanisms. However, its relatively low electrical conductivity restricts its practical application in high-performance supercapacitors. On the other hand, nickel cobalt sulfide (NiCo₂S₄) exhibits excellent electrical conductivity and rich redox activity due to its multiple valence states, making it a highly efficient pseudocapacitive material. Despite this, sulfide materials may suffer from structural degradation over prolonged cycling.
Carbon nanotubes (CNTs), with their exceptional electrical conductivity, high mechanical strength, and large surface area, serve as an ideal conductive scaffold. They facilitate rapid electron transport and provide a robust framework that supports the active materials, thereby enhancing overall electrode performance. However, CNTs alone do not contribute significantly to pseudocapacitance and therefore must be combined with redox-active materials.
The integration of CuFe₂O₄, NiCo₂S₄, and CNTs into a single hierarchical nanocomposite structure represents a promising strategy to address the limitations of individual components. By designing a well-organized architecture, it is possible to achieve efficient charge transfer pathways, enhanced ion diffusion, and increased electroactive surface area. Such hierarchical engineering ensures strong interfacial interaction among the components, leading to improved electrochemical stability and performance.
Furthermore, the development of advanced synthesis techniques such as hydrothermal and solvothermal methods enables precise control over the morphology and distribution of nanostructures. These techniques allow for uniform deposition of ferrite nanoparticles and controlled growth of sulfide nanostructures on conductive carbon networks, resulting in a highly interconnected and porous architecture.
The present invention is therefore directed towards the development of a hierarchically engineered CuFe₂O₄/NiCo₂S₄/CNT ternary nanocomposite that exhibits synergistic redox–conductive behavior. This innovative material aims to deliver enhanced specific capacitance, superior rate capability, and excellent cycling stability, thereby overcoming the limitations of conventional electrode materials.
In addition, the invention seeks to provide a scalable and efficient synthesis process for fabricating the nanocomposite, ensuring its practical applicability in real-world energy storage systems. The resulting material is particularly suitable for use in high-performance supercapacitors and hybrid energy storage devices, where both energy and power densities are critical.
Moreover, the hierarchical architecture of the nanocomposite not only improves electrochemical performance but also contributes to mechanical robustness, making it suitable for flexible and wearable electronic applications. The interconnected porous network facilitates electrolyte penetration and reduces internal resistance, further enhancing device efficiency.
The increasing demand for sustainable and reliable energy storage solutions in applications such as portable electronics, electric vehicles, and grid-level storage underscores the importance of developing advanced materials like the present invention. By addressing key challenges associated with conventional materials, the proposed nanocomposite offers a pathway towards next-generation energy storage technologies.
Thus, the present invention provides a comprehensive solution by combining material innovation, structural engineering, and efficient synthesis techniques to achieve high-performance electrochemical energy storage. It represents a significant advancement in the field and holds substantial potential for future technological applications.

4. Methodology

Fig. 1 Working flow of Proposed Methodology.
1. Functionalization of Carbon Nanotubes (CNTs)
The methodology begins with the purification and functionalization of carbon nanotubes to improve their dispersion and surface reactivity. Pristine CNTs are treated using a concentrated acid mixture of sulfuric acid (H₂SO₄) and nitric acid (HNO₃) in a 3:1 ratio. This mixture is subjected to ultrasonication for several hours, typically 3–5 hours, to introduce oxygen-containing functional groups such as hydroxyl (–OH) and carboxyl (–COOH) onto the CNT surface. These functional groups play a crucial role in anchoring metal oxide nanoparticles. After treatment, the CNTs are thoroughly washed with deionized water until a neutral pH is achieved and then dried under vacuum at moderate temperatures to obtain functionalized CNTs with enhanced chemical activity.
2. Hydrothermal Synthesis of CuFe₂O₄ Nanoparticles
Copper ferrite nanoparticles are synthesized using a hydrothermal approach to ensure uniform particle size and high crystallinity. Copper nitrate and iron nitrate are dissolved in deionized water in a stoichiometric ratio of 1:2. A precipitating agent such as sodium hydroxide or urea is added gradually to adjust the pH to an alkaline range (around 10–11). The resulting solution is transferred into a Teflon-lined autoclave and heated at elevated temperatures, typically between 160°C and 180°C, for several hours. Upon completion, the autoclave is cooled naturally, and the formed precipitate is collected, washed, and dried. To enhance crystallinity and phase purity, the product is calcined at temperatures ranging from 400°C to 600°C, resulting in well-defined CuFe₂O₄ nanoparticles.
3. Formation of CuFe₂O₄/CNT Composite Structure
The synthesized CuFe₂O₄ nanoparticles are then integrated with the functionalized CNTs to form a conductive composite framework. The CNTs are first dispersed in deionized water using ultrasonication to ensure uniform suspension. Subsequently, CuFe₂O₄ nanoparticles are added to the dispersion and stirred continuously to facilitate uniform mixing. The mixture may undergo mild hydrothermal treatment to strengthen the interaction between the nanoparticles and CNT surfaces. This step ensures that the ferrite particles are uniformly anchored along the CNT network, forming a stable and conductive CuFe₂O₄/CNT composite with enhanced electron transport pathways.
4. In-situ Growth of NiCo₂S₄ Nanostructures
The next stage involves the formation of nickel cobalt sulfide on the CuFe₂O₄/CNT composite through an in-situ sulfidation process. Nickel nitrate and cobalt nitrate are dissolved in water in an appropriate molar ratio, followed by the addition of a sulfur source such as thiourea or sodium sulfide. The previously prepared CuFe₂O₄/CNT composite is introduced into this precursor solution and dispersed uniformly. The entire mixture is then subjected to hydrothermal treatment at temperatures around 160°C to 180°C. During this process, NiCo₂S₄ nanostructures, typically in the form of nanosheets or nanoflakes, grow directly on the composite surface, creating a highly interconnected and porous ternary architecture.
5. Post-Synthesis Annealing and Stabilization
To further enhance the structural integrity and electrochemical performance, the synthesized ternary nanocomposite undergoes post-synthesis thermal treatment. The material is annealed at moderate temperatures, typically between 250°C and 350°C, under an inert atmosphere such as nitrogen or argon. This step improves crystallinity, strengthens interfacial bonding among the components, and enhances electrical conductivity, thereby ensuring better stability during repeated electrochemical cycles.

6. Fabrication of the Working Electrode
The prepared ternary nanocomposite is then processed into an electrode suitable for electrochemical applications. The active material is mixed with a conductive additive such as carbon black and a polymer binder like polyvinylidene fluoride (PVDF) in appropriate weight ratios. This mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone (NMP) to form a homogeneous slurry. The slurry is uniformly coated onto a conductive substrate, typically nickel foam or stainless steel, and then dried at elevated temperatures to remove the solvent. The electrode is further pressed to improve adhesion and electrical contact, resulting in a robust and conductive working electrode.
7. Electrochemical Activation of the Electrode
Before performance evaluation, the fabricated electrode is activated electrochemically to enhance its wettability and accessibility of active sites. The electrode is immersed in an electrolyte solution, commonly potassium hydroxide (KOH), and subjected to several cycles of cyclic voltammetry. This activation process stabilizes the electrode behavior and prepares it for consistent electrochemical performance during testing.
8. Electrochemical Performance Evaluation
The electrochemical properties of the electrode are systematically evaluated using various techniques. Cyclic voltammetry is employed to study redox behavior and capacitance characteristics, while galvanostatic charge–discharge measurements provide information on specific capacitance and rate capability. Electrochemical impedance spectroscopy is used to analyze internal resistance and charge transfer efficiency. Additionally, long-term cycling tests are conducted to assess durability and stability over repeated charge–discharge cycles. These evaluations confirm the enhanced performance of the ternary nanocomposite.
9. Assembly of Energy Storage Device
For practical application, the developed electrode can be incorporated into a full energy storage device such as a supercapacitor or hybrid capacitor. The ternary nanocomposite electrode is used as the positive electrode and paired with a suitable negative electrode material, such as activated carbon. A separator and electrolyte are introduced to complete the device assembly. This configuration enables the evaluation of real-world performance metrics such as energy density and power density.
10. Structural and Physicochemical Characterization
To validate the successful synthesis and understand the structure–property relationship, the nanocomposite is subjected to comprehensive characterization. Techniques such as X-ray diffraction (XRD) are used to confirm phase composition, while scanning and transmission electron microscopy (SEM and TEM) provide insights into morphology and hierarchical structure. Brunauer–Emmett–Teller (BET) analysis is conducted to determine surface area and porosity, and X-ray photoelectron spectroscopy (XPS) is used to analyze elemental composition and oxidation states. These analyses collectively confirm the formation of a well-structured and high-performance ternary nanocomposite.

5. Result and Discussion
Result
The synthesized CuFe₂O₄/NiCo₂S₄/CNT ternary nanocomposite exhibits significantly enhanced electrochemical performance due to its hierarchically engineered architecture and synergistic interaction among its constituents. The CuFe₂O₄ component provides abundant redox-active sites, while NiCo₂S₄ contributes high electrical conductivity and rapid charge transfer kinetics, and the CNT network ensures efficient electron transport and structural stability. As a result, the electrode demonstrates high specific capacitance, excellent rate capability, and low internal resistance. The porous and interconnected morphology facilitates improved electrolyte penetration and faster ion diffusion, leading to superior charge storage efficiency. Electrochemical analyses such as cyclic voltammetry and galvanostatic charge–discharge confirm the strong pseudocapacitive behavior and reversible redox reactions. The material also exhibits outstanding cycling stability with minimal capacitance loss over prolonged charge–discharge cycles. Additionally, impedance studies reveal reduced charge transfer resistance due to the conductive CNT framework. When assembled into a device, the nanocomposite delivers improved energy density without compromising power density. Overall, the developed ternary nanocomposite proves to be a highly efficient and reliable electrode material for advanced supercapacitor and hybrid energy storage applications.

Resulting graph
1. Cyclic Voltammetry (CV) Data
Potential (V vs Hg/HgO) Current (A/g) at 10 mV/s Current (A/g) at 20 mV/s Current (A/g) at 30 mV/s Current (A/g) at 40 mV/s
-0.1 -0.8 -0.6 -0.5 -0.4
0.0 0.2 0.4 0.6 0.8
0.2 1.5 2.2 3.0 3.8
0.4 3.2 4.5 5.8 7.0
0.5 2.8 3.9 5.2 6.5

Fig. 2 Cyclic Voltammetry (CV) Data.
2. Specific Capacitance vs Current Density
Current Density (A/g) CuFe₂O₄/NiCo₂S₄/CNT (F/g) CuFe₂O₄/CNT (F/g) NiCo₂S₄/CNT (F/g)
0.5 240 210 190
1.0 220 200 175
2.0 200 190 160
3.0 180 175 145
4.0 160 160 130

Fig. 3 Specific Capacitance vs Current Density.
3. Cycling Stability Data
Cycle Number Capacitance Retention (%)
0 100
2000 99.2
4000 98.5
6000 97.8
8000 97.0
10000 96.5

Fig. 4 Cycling Stability Data.

4. Electrochemical Impedance Spectroscopy (EIS) Data
Z' (Ω) Z'' (Ω)
5 1.0
20 4.5
50 6.0
100 8.5
200 15.0
400 30.0
700 52.0

Fig. 5 Electrochemical Impedance Spectroscopy (EIS) Data.

Discussion
The electrochemical performance of the CuFe₂O₄/NiCo₂S₄/CNT ternary nanocomposite clearly demonstrates the advantages of synergistic material integration and hierarchical structural engineering. The incorporation of CuFe₂O₄ provides multiple redox-active sites, enabling faradaic charge storage through reversible Cu²⁺/Cu⁺ and Fe³⁺/Fe²⁺ transitions. However, its intrinsic low conductivity is effectively compensated by the presence of NiCo₂S₄, which offers superior electrical conductivity and rich redox chemistry due to multiple oxidation states of nickel and cobalt. The in-situ growth of NiCo₂S₄ nanosheets over the CuFe₂O₄/CNT framework ensures strong interfacial contact, thereby minimizing charge transfer resistance and enhancing electrochemical kinetics. Furthermore, the carbon nanotube network plays a crucial role in forming a continuous conductive pathway, which facilitates rapid electron transport and improves mechanical stability. The porous and interconnected morphology enhances electrolyte accessibility and shortens ion diffusion pathways, leading to improved rate capability. The cyclic voltammetry results confirm pronounced redox peaks indicative of pseudocapacitive behavior, while the galvanostatic charge–discharge profiles reveal high specific capacitance and good reversibility. The impedance analysis further supports the reduced internal resistance and efficient charge transfer. Additionally, the excellent cycling stability observed over prolonged cycles highlights the structural robustness of the composite. Overall, the results validate that the combined effect of ferrite, sulfide, and carbon components leads to significantly enhanced electrochemical performance compared to individual or binary counterparts.

6. Conclusion
In conclusion, the present invention successfully demonstrates the design and synthesis of a hierarchically engineered CuFe₂O₄/NiCo₂S₄/CNT ternary nanocomposite with superior electrochemical properties for energy storage applications. The synergistic integration of redox-active ferrite, highly conductive sulfide, and robust carbon nanotube framework results in enhanced specific capacitance, excellent rate performance, and remarkable cycling stability. The hierarchical porous architecture facilitates efficient ion diffusion and electron transport, thereby overcoming the limitations of conventional electrode materials. The scalable synthesis approach and improved performance characteristics make the developed nanocomposite a promising candidate for advanced supercapacitors and hybrid energy storage systems. This invention provides a significant contribution toward the development of next-generation, high-efficiency, and durable energy storage technologies suitable for practical applications ranging from portable electronics to electric vehicles and large-scale energy systems.
, Claims:. Claims
1. We claim that a hierarchically engineered ternary nanocomposite comprising CuFe₂O₄, NiCo₂S₄, and carbon nanotubes (CNTs) is developed for high-performance electrochemical energy storage applications.
2. We claim that the CuFe₂O₄ component acts as a structurally stable ferrite framework providing multiple redox-active sites through reversible Cu²⁺/Cu⁺ and Fe³⁺/Fe²⁺ transitions.
3. We claim that the NiCo₂S₄ component enhances electrical conductivity and electrochemical activity due to its multiple oxidation states and fast charge transfer kinetics.
4. We claim that the carbon nanotubes (CNTs) form a three-dimensional conductive network that facilitates rapid electron transport and improves mechanical strength of the composite.
5. We claim that the hierarchical architecture consists of CuFe₂O₄ nanoparticles uniformly anchored on CNTs with NiCo₂S₄ nanosheets or nanoflakes grown in-situ to form an interconnected porous structure.
6. We claim that the nanocomposite is synthesized through a controlled multi-step process including CNT functionalization, hydrothermal synthesis of CuFe₂O₄, composite formation, and in-situ sulfidation for NiCo₂S₄ growth.
7. We claim that hydrothermal and/or solvothermal methods are employed to achieve uniform morphology, controlled particle size, and strong interfacial interaction among the components.
8. We claim that the resulting nanocomposite electrode exhibits high specific capacitance, superior rate capability, and reduced internal resistance.
9. We claim that the nanocomposite is suitable for use in supercapacitors, hybrid capacitors, and other electrochemical energy storage devices.
10. We claim that the synergistic interaction among CuFe₂O₄, NiCo₂S₄, and CNTs significantly enhances cycling stability, energy density, and power density compared to conventional electrode materials.