The Effect of Bio‐inspired Co‐electrolytes for Enhancement of Electrochemical Properties of Supercapacitors

Abstract

Throughout the earlier times, major efforts have been dedicated to energy-storing materials for their applications in supercapacitors. Supercapacitors that are typically divided into electric double-layer capacitor, pseudo-type capacitors, and hybrid capacitors; [1,2] which has engrossed an excessive impact of interest equally in industrial as well as academic research. Electric double-layer capacitors have extended so much of attention. [1-4] High power densities and excellent cyclabilities have led to their use in everyday devices. These electric double-layer capacitors are commonly organized of two electrodes divided by a permeable membrane saturated by a liquid electrolyte. These are primarily used because of the different benefits of supercapacitors above fuel cells and batteries, comprising greater power densities which are encouraged due to fast charge-discharge rates and long cycles stabilities. [5,6] The power and energies densities of supercapacitors depend on their specific capacitance. The electrolyte is a component that yields an electrically conducting fluid when dissolved in a polar solvent, for example, water. The dissolved electrolyte splits into anions as well as cations, which separate evenly in the solvent. The electrolyte is electrically neutral when an electric potential is applied to the electrolytic solution, the cations move toward the electrode, which has ample of electrons. In contrast, the anions attract to the electrode, which has a deficiency of electrons. [7,8] The existence of smaller de-solvated anions effects in a more ionic adsorption density while using larger cations. Additionally, with smaller anions, the surface area comes to be accessible to ion adsorption, enhancing the specific capacitance of the subsequent material. [7-9] There are many aqueous electrolytes have been used for the electrochemical characterization of supercapacitors such as 1 M sulfuric acid, 6 M KOH, 1 M sodium sulfate, potassium chloride, etc. [10-12] Researchers also have used the ionic liquid as an electrolyte for the electrochemical characterization of electrode materials, which deals with the voltage of supercapacitors. [13] The deep eutectic solvents (DES) are opening electrifying and different prospects as encouraging future generation modern fluids. [14,15] Comparing with ionic liquids, DES show attractive benefits, for instance, higher biodegradability, biocompatibility, very less toxicity and lower cost. The solvent properties can be altered by modestly varying nature as well as the mole fraction of the constituents. These unique advantages make it bio-inspired to use it as electrolytes. [16,17] In the latest years, perpetual efforts have been taken for accepting and adapting the properties of electrolytes for supercapacitors. For instance, A. R. Koh and research group examined the result of cation size in the electrolyte of quaternary ammonium salts. [8] S. Park et al. studied dual salt electrolytes to devastate the solubility issues of electrolytes. The smaller size of the Tetramethylammonium ...

One‐step Preparation of Conducting Polymer/Metal Oxide Doped RGO Trinary Composite for Supercapacitor Applications

“…From the data obtained (Figure 6c), it can be witnessed that the specific capacitances diminished with higher current densities, this observed due to the inadequate ion diffusion of electrolyte, less movement of ions in the porous form of RPM electrode. [62,63] Figure 6e represents the Ragone plot for energy and power densities for RPM measured as per equation (4) and (5). The cyclic stability of RPM electrode was moreover considered by constant charge-discharge for 6000 repetitive cycles at a constant current density of 10 A/g, (Figure 6f).…”

“…The specific capacitance calculated by using equation (3), which indicated the obtained values 592, 465, 388, 310, and 249 F/g at current densities 1, 2, 3, 4, and 5 A/g, respectively (Figure d). From the data obtained (Figure c), it can be witnessed that the specific capacitances diminished with higher current densities, this observed due to the inadequate ion diffusion of electrolyte, less movement of ions in the porous form of RPM electrode . Figure e represents the Ragone plot for energy and power densities for RPM measured as per equation (4) and (5).…”

Bioinspired Materials for Energy Storage

“…Besides the electrodes, nature provides many inspirations for designing the electrolytes for supercapacitors as well. [212] As is known, the mechanical merits of natural bone are highly associated with the hydrated layer that connects the organic polysaccharide protein layer with the inorganic hydroxyapatite layer. [213] A bioinspired water-mediated composite electrolyte, by incorporating a crystallohydrate phase into a polymer matrix, possessed a three-phase structure (Figure 8c), that is, a high-strength crystallohydrate phase, a tough polymer phase, and a sandwiched water layer, which brought about excellent mechanical properties and high ionic conductivity for the solidstate supercapacitors.…”

Development of a Novel Bio‐based Redox Electrolyte using Pivalic Acid and Ascorbic Acid for the Activated Carbon‐based Supercapacitor Fabrication

“…Research has also been devoted towards bio‐inspired electrocytes as more sustainable options. In this context, bio‐electrolytes show attractive benefits, such as higher biocompatibility, biodegradability, less toxicity, and lower cost compared to ILs and conventional aqueous electrolytes [19] . Various bio‐electrolytes, including waste materials, such as biodegradable pectin‐guar gum, gelatin, chitosan, starch, and natural rubber with numerous properties like conductivity, resistivity, and thermal stability, have enormous potential to use as electrolytes in supercapacitors [20] .…”