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Electrode materials comprising SnO2 quantum dots embedded within ZnO hexagonal prisms were successfully synthesized for building cost-effective energy-storage devices. Extensive structural and functional characterizations were performed to assess the electrochemical performance of the electrodes. SEM–EDS results confirm a uniform distribution of SnO2 quantum dots across ZnO. The integration of SnO2 quantum dots with ZnO hexagonal prisms markedly improved the electrochemical behavior. The analysis of electrode functionality conducted in a 3 M KOH electrolyte revealed specific capacitances of 949.26 and 700.68 F g⁻1 for SnO2@ZnO and ZnO electrodes, respectively, under a current density of 2 A g⁻1. After undergoing 5,000 cycles at a current density of 15 A g⁻1, the SnO2@ZnO and ZnO electrodes displayed impressive cycling stability, maintaining specific capacitance retention rates of 89.9 and 92.2%, respectively. Additionally, a symmetric supercapacitor (SSC) device constructed using the SnO2@ZnO electrode showcased exceptional performance, exhibiting a specific capacitance of 83 F g⁻1 at 1.2 A g⁻1. Impressive power and energy densities were achieved by the device, with values reaching 2,808 and 70.2 W kg⁻1, respectively. Notably, the SnO2@ZnO SSC device maintained a capacity preservation of 75% throughout 5,000 galvanostatic charge–discharge sequences. The outcomes highlight the potential of SnO2@ZnO hexagonal prisms as candidates for energy-storage applications, offering scalability and cost-effectiveness. The proposed approach enhances the electrochemical performance while ensuring affordability, facilitating the creation of effective and financially feasible energy storage solutions.

A trimetallic heterojunction-derived Co3S4/NiS2/Cu2S with different ratios through a two-step hydrothermal method was successfully synthesized, showing multifunctional properties such as excellent electrochemical behavior and high photocatalytic activity. Both electrochemical and photocatalytic performances were optimized by adjusting the concentration of Cu without any change in Co and Ni concentrations. Among the synthesized nanocomposites, CNCS-0.15 (Co3S40.5/NiS20.5/Cu2S0.15) depicted the maximum specific capacity of 464.16 C g–1 at 1 A g–1 as revealed from electrochemical measurements. Further for real-time usage, assembling of a hybrid supercapacitor CNCS-0.15-(+)||activated carbon(−) furnished an energy density of 84.95 W h kg–1 at a power density of 1134 W kg–1 with good capacity retention of 93.64% for 5000 cycles. In addition, CNCS-0.15 also displayed remarkable photocatalytic performance under visible light illumination by utilizing Congo red (CR) dye. It could effectively degrade 91% of CR (40 mg L–1) through a double Z-scheme mechanism owing to the charge carriers' availability with higher redox ability. The Mott–Schottky analysis along with the scavenging experiment confirmed the involvement of h+ and O2–. radicals in the photodegradation. Due to highly interconnected nanoflake architectures, CNCS-0.15 holds a promising application as a supercapacitor electrode and visible light active photocatalyst. [ABSTRACT FROM AUTHOR]

High‐performance supercapacitive electrode materials have received significant attention from researchers worldwide, thus aiming for comparable performance similar to the extensively used rechargeable batteries. For emerging energy storage technologies like flexible supercapacitors, transition metal chalcogenides (TMCs) have been in the spotlight due to their promising electrochemical features compared to other electrode materials. Among the synthesis techniques, electrodeposition‐mediated preparation of thin films of TMCs offered an affordable binder‐free approach for electrode fabrication that effectively improved the supercapacitor performance. Hence, this review mainly focussed on the electrodeposition‐based syntheses of single/ multinary chalcogenides and their composites for supercapacitors applications. Further, the effects of different deposition parameters were discussed for boosting the supercapacitor performance. Finally, this review outlined the existing challenges and future perspectives in this research domain, which will assist the upcoming exploration in the energy storage field. [ABSTRACT FROM AUTHOR]

In the recent times research towards solid state supercapacitors (SSS) have increased drastically due to the promising performance in futuristic technologies particularly in portable and flexible electronics like smart watches, smart fabrics, foldable smartphones and tablets. Also, when compared to supercapacitors using liquid electrolyte, solid electrolyte has several advantages like high energy density, safety, high cycle life, flexible form factor, and less environmental impact. The crucial factor determining the sustainability of a technology is the eco‐friendliness since the natural resources are being exploited in a wide scale. Numerous studies have focused on biodegradable materials for supercapacitor electrodes, electrolytes, and other inactive components. Making use of these biodegradable materials to design a SSS enables the technology to sustain for a very long time since biodegradable materials are not only environment friendly but also, they show relatively high performance. This review focuses on recent progress of different biodegradable electrodes, and electrolytes along with their properties, electrochemical performance and biodegradable capabilities for SSS have been analyzed and provides a concise summary enabling readers to understand the importance of biodegradable materials and to narrow down the research in a more rational way. [ABSTRACT FROM AUTHOR]

This work reports the synthesis of semiconductor selenium nanoparticles/micro-rods (Se-NP/MRs) using the bio-fabrication approach and studies its photocatalytic activity under natural sunlight irradiation. Cabbage leaf extract was used as a reducing agent to fabricate Se-NP/MRs. X-ray diffraction patterns shown the crystalline structure with a crystallite size of 28.17 nm, conferring to planes of hexagonal structure. A characteristic sharp resonance peak in Raman spectra at 235 cm−1 endorsed to the Se – Se bond of crystalline Se-NP/MRs. The prominent peak in the FTIR spectra at 621 cm−1 supported the formation of Se-NP/MRs. Scanning electron micrograph revealed a nearly spherical shape with irregular layers in the 35‒95 nm size range. In contrast, the dimension of the micro-rods was observed to be ~ 10 µm in length and 2.5 µm in diameter. The bandgap energy of Se-NP/MRs was analysed to be 2.14 eV using the Tauc plot. The exciting photocatalytic performance of the bio-fabricated Se-NP/MRs revealed that the methylene blue degradation was ~ 86% in 40 min and ~ 97% in 140 min. Kinetic analysis shows that the pseudo-second-order correlation coefficient is well fitted compared to the pseudo-first-order. Therefore, this work opens the door to further exploration of nano-materials/composites with mixed nanoparticles/micro-rods morphology for sustainable applications in the removal of various textile and industrial contaminants. [ABSTRACT FROM AUTHOR]

Mixed multimetallic-based nanocomposites have been considered a promising functional material giving a new dimension to environmental remediation and energy storage applications. On this concept, a hybrid ternary CoO/Ni(OH)2/Cu(OH)2 (CNC) composite showing sea-urchin-like morphology was synthesized via one-pot hydrothermal approach, and its photocatalytic and electrochemical performances were investigated. The photocatalytic performance was explored using Congo red (CR) as a dye pollutant under visible light illumination. The presence of mixed phases of ternary metal ions could minimize the recombination efficacy of photogenerated charge carriers on the basis of the heterojunction mechanism, resulting in 90% degradation of CR dye (40 mg L−1). The effect of scavengers coupled with electrochemical experiments revealed O2−. radical as the predominating species responsible for the degradation of CR. From the electrochemical analysis of CNC, the well-distinguished redox peaks indicated the redox-type nature with a specific capacity of 405 C g−1. For practical applications, an supercapattery (CNC(+)|KOH|AC(−)) was assembled furnishing an energy density of 42 W h kg−1 at a power density of 5160 W kg−1 at 5 A g−1 along with a high capacity retention and coulombic efficiency of 98.83% over 5000 cycles. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]