Solid State Phenomena Vol. 363

Abstract: In this paper, the effect of two additives on the plasticity properties and drying sensitivity of a Hungarian clay were investigated. Two different sodium tripolyphosphate-based commercially available plasticizers (Fabutit 734, Budit 8H) were applied for experiments. The amount of the additives in the clay mass was changed between 0 and 0.5wt% relative to the weight of the dry clay and the plasticity was measured with two different methods. In addition to the plasticity of the clay mixes, the effect of the additives on the drying sensitivity was also analyzed with the Macey method. Results showed that the moisture content required to shape the clay body can be reduced by 1-1.5% with the mixing 0.1 and 0.2 wt% of Budit 8H additive.

Abstract: In this study, the high specific capacitance material based on activated carbon-manganese dioxide (AC/MnO₂) composite was prepared by an impregnation method. The MnO₂ particle was synthesized via a redox reaction between KMnO₄ and lemon peel extract as a bioreductor. The steps taken in this research were the preparation of lemon peel extract, then synthesis of MnO₂ using lemon peel extract, synthesis of AC/MnO₂ composites, and electrodes characterization using powder XRD, SEM, and CV. According to the results, the AC/MnO₂ composite electrode had a higher specific capacitance compared to the synthesized MnO₂. The powder XRD test results show that the synthesized MnO₂ consisted of α, γ, and δ polymorphs. SEM data show that the average MnO₂ particle size is 482.80 nm. The CV test results show that the highest AC/MnO₂ capacitance is 188.17 F g^-1 which was obtained at an AC/MnO₂ ratio is 1:1. This suggests that the AC/MnO₂ composite material has the potential to be used as a supercapacitor electrode material.

Abstract: Developing energy storage systems has become a significant focus in supporting advancing renewable energy technologies and electric vehicles. Supercapacitors are a critical device in this endeavor, known for their high capacitance and low internal resistance. Although carbon-based supercapacitors have been widely used, they have low energy density. This research addresses the development of activated carbon (AC) and polyaniline (PANi) composite-based supercapacitors to improve the performance of energy storage devices. AC/PANi composites were synthesized in various ratios of (20:80)%, (50:50)%, and (80:20)% using in-situ polymerization method. Supercapacitor electrodes were prepared by mixing AC/PANi composite, acetylene black, and polyvinylidene fluoride (PVDF) with a mass ratio of (80:10:10)%. Furthermore, coin-type supercapacitor cells were assembled using AC/PANi composite electrodes, 1 M Et4NBF4 electrolyte, and polypropylene separator. Supercapacitor performance was evaluated using Cyclic Voltammetry (CV) methods. The results of FTIR analysis showed that the AC/PANi composite was successfully synthesized, with absorption peaks corresponding to the characteristics of AC and PANi. X-ray diffraction patterns showed that the AC/PANi composite exhibited amorphous properties. The CV test results show that the coin cell based on the AC/PANi composite (20%:80%) indicates the highest performance with significant specific capacitance. Thus, supercapacitor electrodes based on the AC/PANi composite show potential as active materials for supercapacitor devices.

Abstract: Asymmetric supercapacitors have been fabricated using nanostructured AC// AC-NiCo₂O₄ composite electrodes. The aim was to determine the performance of a modified electrode based on AC as the anode and AC-NiCo₂O₄ as the cathode. NiCo₂O₄ has been successfully synthesized using the co-precipitation method. FTIR, XRD, and SEM characterized the material. The NiCo₂O₄ confirmed the crystalline structure assigned to cubic spinel with nanospheres morphologies. The electrochemical properties of the prepared composite electrodes and fabricated supercapacitor cells have been studied using charge-discharge (CD) and cyclic voltammetry (CV) in 1M Et₄NBF₄ as an electrolyte_. The optimized composition is AC-NiCo₂O₄ (15%), exhibiting a superior power density of 42.56 W kg^-1. These results showed that AC-NiCo₂O₄ material could be a great candidate as an active material for supercapacitors.

Abstract: This study proposes a simple method for fabricating metal particles. Metal nanoparticles are synthesized in an aqueous solution. The synthesis method is based on the galvanic replacement of one metal with another, i.e., the deposition of a metal on the surface of another metal using difference between the standard electrode potentials of the metals under ultrasonication. An aqueous colloidal solution of metallic copper (Cu) nanoparticles is prepared using Cu acetate and a metallic zinc (Zn) plate. A similar colloidal solution of metallic Cu nanoparticles is prepared using Cu acetate and a metallic iron plate. No metallic nanoparticles are obtained using metallic aluminum and nickel (Ni) plates because of the formation of passivated layers. An aqueous colloidal solution of metallic Ni nanoparticles is prepared using Ni acetate and a metallic Zn plate; however, Ni_0.7Zn_0.3O is also formed. The results of the study show that the proposed method can be used to produce metallic particles in a simple manner.

Abstract: The nanosized samarium doped tin oxide in varying concentration (0%, 0.5%, 1%, 3%, 5%) was successfully synthesized using the wet chemical precipitation approach. X-ray Diffraction (XRD) analysis was done to monitor the effect of the dopant concentration to the host lattice as broadening and narrowing of the formed peaks are seen. Average crystallite sizes of the produced sample are ranging from 9-28 nm, confirming it to be nanoscale. Identified peaks with Miller indices of ((110), (101), (200), (111), (211), (220), and (002) signifies a tetragonal rutile structure of the synthesized samples. Scanning Electron Microscopy (SEM) shows the difference in morphology for the powdered samples as per different samarium loading as well as the shape, which is granular. Energy Dispersive X-ray spectroscopy (EDX) affirms the successful integration of the samarium dopant to the lattice structure of the SnO₂.

Abstract: This study aimed to evaluate filter efficiency for TiO₂ nanoparticle deposition across varied water chemistry and simulated conditions. The experimental results provided collision attachment efficiencies (α) of 0.001, 0.002, and 0.01 and filter coefficients (λ) of -0.003, -0.01, and -0.02. The authors used these collision attachment efficiencies to assess filter efficacy under simulated conditions, mainly removing naturally occurring nanoparticles spanning sizes from 1 to 100 nm. This experiment uncovered a strong correlation between TiO₂ nanoparticle deposition and water ionic strength, with aggregation becoming more pronounced as ionic strength increased. This phenomenon was especially prominent in instances lacking alum addition. Notably, the presence of alum resulted in the nanoparticles maintaining a dispersed state in the water, attaining enhanced stability by introducing excessive positive charges. Consequently, this study underscores how manipulating water's ionic strength can effectively induce nanoparticle destabilization during filtration. The implications of these findings are significant, as practical data about the behavior of diminutive like TiO₂ nanoparticles has been notably lacking.