## 3 Results
### Electrochemical Characterization  
The functioning of carbon composite electrodes with a high surface area in a supercapacitor setup depends on developing an electrochemical double layer at the boundary between the electrode and the electrolyte. The double layer enables enhanced adsorption and desorption of ions from the electrolyte due to the larger surface area. A cyclic voltammetry analysis was carried out to evaluate the electrochemical performance of the three carbon composite electrodes and determine their stability compared to a reference electrode made of silver wire, through a three-electrode cell (a half-cell setup). This setup allows an accurate measurement due to the presence of a reference electrode and good control, which minimizes unwanted side reactions. This ensures better control over the reaction kinetics due to the separation of the counter and working electrodes. Some limitations also need to be considered when moving from a complex setup, and when applying the setup in a real system. The two-electrode setup (full-cell setup) is an important way of evaluating how the electrode-electrolyte system behaves in setup that closely mimics commercial supercapacitors. However, in this work, the authors focused on the study in a three-electrode setup to understand the electrode (coated carbon materials)-electrolyte interface. In the future, the full-cell configuration will be properly addressed in the scale-up process. Figure 12 illustrates the voltammetric behavior of GC electrodes modified by the three biocarbons when scanned at a rate of 50 mV s\({}^{-1}\). Figure 12: Cyclic voltammetry curves (30 \({}^{\circ}\)C, ethaline, 50 mV s\({}^{-1}\)) for gelatine and chondro sulfate-based carbon electrodes. All the cyclic voltammograms exhibited quasi-rectangular voltammetric profiles, suggesting an electric double-layer capacitive behavior [59]. The variations in the shape and current intensity of the curves can be attributed to the differences in the chemical composition, surface structure, and morphology of the carbon materials. Factors such as the degree of graphitization and porosity can contribute to these differences. In general, the shapes of the cyclic voltammograms offer valuable insight into the distinct electrochemical properties of the materials, which can facilitate the development and optimization of materials for various energy storage applications. Figure 13 presents the charge-discharge curves obtained from high-specific-area materials used in a supercapacitor configuration. These curves illustrate the correlation between the electrode potential and the charge stored or released during the charging and discharging. These curves are essential for understanding and improving supercapacitor systems for various applications. Recording charge-discharge curves from high-specific-area materials, such as bio-carbon derived from marine waste, is particularly important, since it provides crucial insight into the electrochemical properties and performance of the electrode material. By analyzing these curves, researchers can better understand how the material behaves during supercapacitors' energy storage and release processes. This knowledge can then be applied to optimize the design and performance of supercapacitor systems for enhanced efficiency and suitability in different applications. Galvanostatic charge-discharge (GCD) curves of the biocarbon composite electrodes exhibit a symmetrical triangular shape, with distinct charge and discharge time scales. However, their performance (as shown in Table 5) varies, indicating the behavior of electric double-layer capacitors and the high reversibility of the carbon electrodes [60]. Notably, the blue shark chondro sulfate-based carbon showcases higher capacitance (40 F g\({}^{-1}\)) compared to the commercial chondro sulfate-based carbon (25 F g\({}^{-1}\)), followed by the blue shark gelatine-based carbon (7 F g\({}^{-1}\)), at a current density of 1 A g\({}^{-1}\).