Global energy consumption is increasing exponentially as a result of the rising population and fast industrialization. As a result, energy has been given top priority in addressing the needs of our modern civilization [1]. Fossil fuels currently serve as the primary source of energy and provide the diverse spectrum of energy needs in various industries. Unfortunately, the availability of fossil fuels is steadily decreasing, and our planet is constantly in danger as a result of the massive environmental degradation these sources produce. According to some studies, by the middle of the century, the world's energy needs would have doubled, and by 2100, they would have tripled [2]. In addition, the widespread use of electronic gadgets, such as wearable technology, digital cameras, laptops, and mobile phones, as well as hybrid electric cars, has prompted the development of transportable forms of energy. In the report, Bosch's (2007–2022 current state of affairs and expenditure prospects of supercapacitor market in China), the worldwide market of supercapacitors has extended US dollars up to $16 × 109 in 2015, and evaluators look for the market of the supercapacitor to outrun in 2020 up to $92.3 × 109, with a 39 % multiple yearly growth rates. From this view, the progress of the supercapacitor market in the whole world is rising [3]. The development of extremely effective energy conversion as well as storage technologies has been a continuous endeavor in this context. Due to their high energy/power densities, prolonged lives, and quick charging-discharging capabilities, energy storage technologies including supercapacitors, fuel cells, and rechargeable batteries are regarded as viable options for meeting a variety of energy demands [4].

Supercapacitors, also known as ultra-capacitors, are among the most attractive devices for storing energy because of their high power density (PD) (>10 kW kg⁻¹), fast rate capability, and extended cycle span (>10,00,000 cycles). Supercapacitors have a distinct advantage over batteries in that their PDs are higher. Even while they have energy densities (EDs) that are many times greater than those of conventional capacitors, compared to fuel cells and batteries, they are nonetheless significantly lower. Supercapacitors thus fill a need by bridging the energy and power gap between fuels/batteries and conventional dielectric capacitors. Since 1957, when Becker first requested a patent on an electrochemical capacitor, a lot of work has been spent on studying effective supercapacitors [5,6]. High PD has been particularly needed in recent years to fulfill the growing demands of advanced applications including energy incremental backups, electronic gadgets, and hybrid electric vehicles, Supercapacitor research is exploding, and scientists have achieved significant advancements in this area. Their main objective is to increase the high PDs of supercapacitors while reducing their EDs, enabling them to serve as a main source of energy similar to batteries.

According to the charge storage mechanism, supercapacitors are categorized into three types; electric double-layer capacitors (EDLC), pseudocapacitors, and hybrid capacitors. Which pseudocapacitor, the quick faradaic reactions occurring at the surface of the electrode, has a larger specific capacitance (Cs) than EDLC. Pseudocapacitor also has the benefit of being inexpensive. However, as conductivity is crucial for achieving high ED and PD, pseudocapacitor materials are only used in a selected number of applications.

In the recent couple of decades, spinel ferrites have had great analyst expeditions because of their creativity flexibility of small losses of eddy current, larger electrical resistivity, the giant value of dielectric constants, excessive initial permeability, and adequate saturation magnetization [[7], [8], [9]]. Due to their superior electrical and magnetic properties, they are widely used in various gadgets such as cell phones stage shifters, large frequency transformer cores, switches, resonators, and more [10].

In comparison to traditional electrochemical capacitors, metal ferrite electrodes exhibit dramatically improved capacitance performance and offer high specific energy and specific power. However, these kinds of capacitors still face a lot of difficulties because of the low cycle stability of faradaic electrodes [11]. In the ongoing search for innovative electrode materials, material costs, and ecological sustainability remain major obstacles. Compared to monometallic oxides, metal iron oxide (MFe₂O₄) materials such as MnFe₂O₄, CuFe₂O₄, NiFe₂O₄, etc. exhibit rich redox properties and improved electrochemical conductivity. The spinel ferrites acquire a cubic spinel structure with two unique adjacent lattice sites: tetrahedral and octahedral sublattices, particularly those that contain the metallic divalent cation M²⁺. Among these materials, MFe₂O₄ (where M might be Mn, Co, Ni, Zn, or Mg) has drawn a lot of attention as a thoroughly studied pseudocapacitive electrode material. MnFe₂O₄ provides different morphologies as well as better electrochemical performance. The supercapacitive performance of materials is largely determined by their morphology. Supercapacitors are energy storage devices that store electrical energy by the electrostatic separation of charge. It is also referred to as electrochemical capacitors or ultracapacitors. The key factors affected by morphology include surface area, porosity, and the accessibility of active sites [12]. Higher surface area materials have more electrochemical reaction sites, which increases their capacity to store charge. Because of their high surface areas, nanomaterials including flakes, nanowires, and nanorods are good candidates for supercapacitor applications. Improved ion diffusion and electrolyte accessibility via porous materials lead to improved charge storage and quicker charge/discharge rates. Mesopore materials are often favored for supercapacitor electrodes. The morphology can influence the electrical conductivity of the material. Well-connected structures, such as networks of nanorods or nanoflakes, facilitate efficient electron transport, reducing internal resistance and enhancing overall device performance [13]. Through functionalization, materials' surface chemistry can be changed to optimise their interaction with electrolytes, which improves capacitance and stability [14].

Manganese ferrite has drawn a lot of interest because of its dielectric qualities, low dielectric losses, affordability, wide availability, eco-friendliness, and noteworthy electrochemical reactivity. This has prompted in-depth investigation and study. J. Kwon et al. studied MnFe₂O₄ hybrid supercapacitors via hydrothermal synthesis. For instance, these supercapacitors displayed a remarkable specific capacitance of 282 F g⁻¹ and showed extraordinary cyclic stability, maintaining 85.8 % of their retention over 2000 cycles [15]. Using a solvothermal synthesis method, Z. Li et al. synthesized MnFe₂O₄ colloidal nanocrystals. The findings of their study achieved a specific capacitance of 88.4 F g⁻¹ at 1 A g⁻¹ with 69.2 % retention over 2000 cycles [16]. A viable electrospinning process was used in the study by Y. Liu et al. to encapsulate MnFe₂O₄ nanodots inside porous N-doped carbon nanofibers. This method demonstrated outstanding high-rate performance obtained 305 mAh g⁻¹ even at 10000 mA g⁻¹ and a prolonged cycling lifespan maintained over 90 % capacity retention over 4200 cycles [17]. P. Junlabhut et al. [18] synthesized MnFe₂O₄ nanoparticles via the chemical co-precipitation method and studied the structural properties of MnFe₂O₄ nanoparticles. A composite material made of PANI and MnFe₂O₄ nanocubes decorated on flexible graphene with a specific capacitance of 338 F g⁻¹. This composite was created utilizing a chemical oxidative polymerization process that was reasonably straightforward, affordable, and environmentally benign by K. Sankar et al. for the utilization of a supercapacitor [19].

In this context, the development of materials using electrodeposition stands as an intriguing and creative approach, providing the dual purposes of morphology alterations and the deposition of active materials for supercapacitor applications. To prepare manganese ferrite thin film electrodes, while varying the deposition time, a binder-free one-step electrodeposition method was used in this study. As the deposition time variation of manganese ferrite was systematically changed, the changes in the structure and morphology of thin films formed from manganese ferrite were investigated using structural and morphological characterization studies. Additionally, research was done to determine how changes in structural and morphological impact the pseudocapacitive performance of manganese ferrite thin film electrodes. Additionally, the ideal manganese ferrite electrode was used as the cathode and a manganese oxide (MnO₂) electrode served as the anode in the construction of the hybrid solid-state supercapacitor device (HSSD) configurations. The discussion included measurements and a display of the supercapacitive properties of the hybrid energy storage device.