Spinel Ferrite-Based Materials for Next-Generation Supercapacitors: A Comprehensive Review of Synthesis, Structure-Property Relationships, Electrochemical Mechanisms, and Future Challenges

Abstract

Ferrite-based nanomaterials have emerged as promising electrode candidates for high-performance supercapacitors due to their low cost, environmental friendliness, rich redox activity, and tunable structural properties. This review systematically examines synthesis strategies, charge-storage mechanisms, and recent advancements in ferrite nanostructures for electrochemical energy storage applications. Various synthesis methods, including hydrothermal, sol-gel, co-precipitation, and electrospinning, are discussed in terms of their effects on morphology, crystallinity, and electrochemical performance. The fundamental charge-storage mechanisms, such as faradaic redox reactions, pseudocapacitance, and ion-diffusion kinetics, are critically analysed to elucidate performance enhancement. Furthermore, the role of composite formation with carbon-based materials, conducting polymers, and metal oxides is highlighted to overcome intrinsic limitations, such as low electrical conductivity and structural instability. Emerging trends, including hierarchical nanostructures, defect engineering, and hybrid electrode design, are also addressed. Finally, the challenges and future perspectives toward the practical implementation of ferrite-based supercapacitors are discussed, providing insights for the development of next-generation energy storage devices.