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This research focused on the detailed analytical characterization of the poultry litter-derived biochar followed by its conversion into electrodes for supercapacitor application. Biochar was prepared from poultry waste by pyrolysis at 600 °C for 3hours and activated it by mixing with potassium hydroxide and re-pyrolyzed at the same temperature for 1hour. Both the biochar and activated biochar were analyzed using Scanning Electron Microscopy (SEM), Infrared spectroscopy (IR), Time of Flight – Secondary Ion Mass Spectroscopy (ToF-SIMS), and X-ray Photoelectron Spectroscopy (XPS), and Brunauer-Emmett- Teller (BET) analyses. SEM analyses suggested that the biochar’s surface became more porous and homogeneous after activation with potassium hydroxide. The specific surface area of biochar increased by more than 200 folds to 814 m2g-1after KOH-activation confirmed from BET analysis. IR indicated the activated biochar contained sulfur- and phosphorous-functional groups but few or no oxygen-functional groups. The decrease in oxides of nitrogen, sulfur, and phosphorous was also observed in ToF-SIMS analysis. In spite of the decrease of oxides, the surface oxygen concentration (At%) increased from 42.3% to 46.6% after activation and was assumed to be present as C-O corroborated by XPS. The specific capacitance of activated biochar calculated from galvanostatic charge-discharge is 152F/g attributed to its hierarchical porosity, heteroatoms presence, and hydrophilicity. This research is expected to contribute towards the sustainable management of agricultural wastes.

A novel symmetrical alkylsulfonyl-substituted poly(phenylenevinylene) derivative, poly [2,5-bis-(2′-ethylhexylsulfonyl)-1,4-phenylene)vinylene] (SO2EH-PPV), was synthesized via palladium-catalyzed Stille coupling, and its electronic and optical properties were investigated. The novel PPV derivative was characterized by NMR, UV–visible absorption, photoluminescence, gel permeation chromatography, infrared spectroscopy, and cyclic voltammetry (CV). The polymer with Mwof 27 800 and a polydispersity index of 2.6 is readily soluble in common organic solvents, such as THF, chloroform, and toluene. The fluorescence quantum yield of the polymer, determined against rhodamine 6G in dilute aqueous solutions, was 0.95. The HOMO and LUMO levels of SO2EH-PPV were calculated to be −6.0 and −3.61 eV, respectively. The results obtained by CV suggest that SO2EH-PPV is a strong electron acceptor polymer. Single layer stable polymer light-emitting diode devices with the configuration of (ITO/PEDOT:PSS/SO2EH-PPV polymer/Al) were fabricated exhibiting a green light emission.

This study performs a comprehensive investigation to objectively analyze the effects of various carbon nanomaterials using as conductive additives (5 wt%) in activated carbon (AC) based electrodes for electrical double-layer capacitors (EDLCs). A variety of carbon nanomaterials including carbon black (CB), single-walled carbon nanotubes (SWCNT), graphene nanoplatelets (GNP), fullerenes (C60), and activated carbon nanofibers (ACNF) are considered in this work as they provide a diverse combination of intrinsic properties such as specific surface area, conductivity, micro-mesoporous structures, and geometry of nanomaterials. These additives are incorporated into freestanding carbon electrodes, and their EDLC performance in a neutral aqueous electrolyte is investigated by means of electrochemical measurements. The findings from this work provide useful insight into how the properties of various carbon nanomaterials influence EDLC performance in different aspects such as capacitive behavior, resistivity, performance at different current densities, charge propagation properties, and stability over long-term cycling. The results show that each carbon additive has its own strengths and limitations for different performance parameters considered. The unfavorable material properties of C60 cause a significant decrease in capacitance at high current density, leading to the lowest device performance incorporated with C60 as additives. While GNP and SWCNT show high crystallinity, low ID/IG ratios, the EDLCs still exhibit decreased specific capacitance and moderate energy densities due to their relatively limited specific surface area and high resistivity of the resultant composite electrodes compared to the pristine AC. The CB additives-based samples demonstrate the highest conductivity of dry electrodes and low equivalent series resistance (ESR) in EDLCs. On the other hand, a reduction in capacitance at high current densities and material degradation during long-term cycling are observed for CB samples, which could be attributed to the high dispersibility of CB causing limited interparticle voids and thus increasing diffusion resistance. In contrast, the use of ACNFs significantly reduces the diffusion resistance and improves the cyclic stability compared with CB based samples due to the advantages of larger specific surface area and superior micro-mesoporous structures of ACNFs. In particular, EDLCs with ACNFs demonstrate an increase in specific capacitance and energy density by 99 % and 76 %, respectively compared to CB based EDLCs at a current density of 20 A/g. This work elucidates the complex interplay between carbon nanomaterials using as additives and corresponding EDLC performance. These results provide important information to the community for future development of new energy conversion and storage devices.

Vanadium oxide nanotubes have shown great promise as electrode materials for energy storage devices. In this study, we report the synthesis of V2O5nanotube (VNT) clusters, which form densely packed radial arrangements of VNTs on high-surface-area carbon fiber fabrics (CF). This was achieved by coating the CF with V2O5by pulsed laser deposition (PLD). Hydrothermal treatment of the PLD films in the presence of excess intercalated V2O5results in formation of well-adhered VNT clusters on the CF. The densely packed VNTs have inner and outer diameters and interlayer distances of ∼24, ∼70, and ∼2.4 nm, respectively. Coin cell type supercapacitors (CR2032) were assembled using VNT-CF as the anode material and electrochemical properties were evaluated.