Optimizing Electrodeposition of Polyaniline on Various Woven Steel Mesh Sizes for Enhanced Supercapacitor Performance

The development of efficient supercapacitors hinges on the innovation of superior electrodes, which are pivotal in augmenting their energy storage capabilities. Supercapacitors, recognized for their high-power density and extended cycle life, play a crucial role as sustainable solutions in addressing energy storage challenges. A fundamental aspect of supercapacitor functionality involves the electrode material, which works in concert with other key components such as the current collector, separator, and electrolyte. This study focuses on evaluating the impact of the current collector material on the performance of symmetric supercapacitors. We investigated the electropolymerization of polyaniline on woven steel mesh current collectors of varying mesh sizes, ranging from 20 to 200 mesh per inch, using assorted deposition conditions. The electrochemically modified woven steel meshes were utilized to construct symmetric supercapacitors. The electrochemical performance of the assembled supercapacitors, configured in a two-electrode system, was investigated using a variety of electrochemical techniques to better understand the kinetics of electrolyte ion migration. Notably, the 20-mesh size, characterized by the fewest pores per inch, demonstrated superior performance with an optimum capacitance of 4730 mF/cm2, an energy density of 317.8 μWh/cm2, and a power density of 400 μW/cm2 at a current density of 1 mA/cm2.

Designing High-Performing Symmetric Supercapacitor by Engineering Polyaniline on Steel Mesh Surface via Electrodeposition

Energy storage is one of the most stimulating requirements to keep civilization on the wheel of progress. Supercapacitors generally exhibit a high-power density, have a maximum life cycle, quick charging time, and are eco-friendly. Polyaniline (PANI), a conductive polymer, is considered an efficacious electrode material for supercapacitors due to its good electroactivity, including pseudocapacitive behavior. Here, we present the fabrication of a symmetric supercapacitor device based on steel mesh electrodeposited with PANI. Due to its effective conductivity, porous nature, and low cost, steel mesh is a good choice as a current collector to fabricate a high-performance supercapacitor at a low cost. The optimum fabricated supercapacitor has a high specific capacitance of ∼353 mF cm^-2 . Furthermore, the supercapacitor obtained an energy density of ∼26.4 μW h cm^-2 at a power density of ∼400 μW cm^-2 . The fabricated supercapacitor shows high stability, as the initial capacitance remained almost the same after 1000 charge/discharge cycles. PANI is a promising candidate for mass production and wide applications due to its low cost and high performance.

An indirect electrochemical method for aqueous sulfide determination in freshwaters using a palladium chelate as a selective sensor

Sulfide anion is a highly toxic and corrosive compound and its presence above the threshold concentrations (i.e. μmol L^-1) in freshwaters may indicate environmental pollution. Besides, the increase in sulfide concentration results in modifications of the organoleptic proprieties of water and air. Many analytical methodologies have been designed for aqueous sulfide quantification, however, due to the high reactivity and instability of sulfide, the pursue of a simple, sensitive, selective, and portable analytical method is still a current demand. In this study, an indirect electrochemical method for the determination of sulfide based on its interaction with a palladium complex - bis(2-aminobenzoate) palladium(II) - acting as a selective chemosensor is described. The reaction leads to the demasking of the electroactive ligand 2-aminobenzoic acid (i.e. anthranilic acid) and square wave voltammetry is employed to monitor its concentration using a glassy carbon electrode (GCE). Experimental conditions were optimized and the reaction was performed in Britton-Robinson (BR) buffer at pH 5 for 4 min, providing the higher magnitude of the analytical signal. A linear relation (r² > 0.99) from 3 to 30 μmol L^-1 of sulfide was obtained with a limit of detection of 0.10 μmol L^-1. Recovery experiments using freshwater samples spiked with sulfide revealed overall satisfactory results for the limit concentration levels permitted by regulatory agencies. Therefore, the proposed methodology shows advantages in terms of portability, selectivity, sensitivity, low-cost, and easiness-to-use enabling monitoring of sulfide in a variety of waters.

Controlled-Potential-Based Electrochemical Sulfide Sensors: A Review

Due to their potential applications in industry and potent toxicity to the environment, sulfides and their detection have attracted the attention of researchers. To date, a large number of controlled-potential techniques for electrochemical sulfide sensors have been developed, thanks to their simplicity, reasonable limit of detection (LOD), and good selectivity. Different researchers have applied different strategies for developing selective and sensitive sulfide sensors. However, there has been no systematic review on controlled-potential techniques for sulfide sensing. In light of this absence, the main aim of this review article is to summarize various strategies for detecting sulfide in different media. The efficiencies of the developed sulfide sensors for detecting sulfide in its various forms are determined, and the essential parameters, including sensing strategies, working electrodes, detection media, pH, LOD, sensitivity, and linear detection range, are emphasized in particular. Future research in this area is also recommended. It is expected that this review will act as a basis for further research on the fabrication of sulfide sensors for practical applications.

A dual emission nanocomposite prepared from copper nanoclusters and carbon dots as a ratiometric fluorescent probe for sulfide and gaseous H2S

A series of dual-emission fluorescent probes was prepared from copper nanoclusters (Cu NCs) and carbon dots (CDs). They show two emission peaks (blue at 469 nm and red at 622 nm) when photoexcited at 365 nm. Upon exposure to sulfide, the Cu NCs will be deteriorated because they react with sulfide to form CuS. This results in the quenching of the red fluorescence of the Cu NCs, while the blue fluorescence of the CDs remains constant. Thus, the color of the nanocomposite changes from red to blue. The ratio of the fluorescences at the two wavelengths decreases linearly in the 2-10 ppb (26-128 nM) sulfide concentration range, and the limit of detection is 0.33 ppb (4.3 nM). The nanocomposite also was placed in an agar gel and then incorporated into a paper strip for fluorometric monitoring of gaseous hydrogen sulfide. Graphical abstract Schematic presentation of the synthesis of Cu NCs (copper nanoclusters)-CDs (carbon dots) dual-emission nano-assembly, Cu NCs-CDs-agar fluorescent film and their application for the detection of sulfide and H₂S.