Publications Internationales

Permanent URI for this collectionhttps://dspace.univ-boumerdes.dz/handle/123456789/13

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    Ternary WO₃–MnO₂@SiNWs hybrid electrodes for high-performance Micro-supercapacitors with enhanced energy density and stability
    (Elsevier, 2025) Boukhouidem, Khadidja; Slimani, Amel; Derkaoui, Khaled; Manfo, Theodore Azemtsop; Hadjersi, Toufik; Manseri, Amar; Selmi, Noureddine; Elhak Abaidia, Seddik
    Advanced energy storage technologies, such as rechargeable Batteries and Micro-supercapacitors (μSCs) play a pivotal role in addressing the growing global energy demand. Improving their energy and power densities requires the development of electrode materials with well-engineered, hierarchical porous architectures. In this work, we report a facile hydrothermal synthesis of WO₃-MnO₂ composite nanostructures directly integrated onto silicon nanowires (SiNWs), which serve as a highly conductive and high-surface-area scaffold. The influence of annealing temperature on the structural, morphological, and electrochemical properties of the WO₃-MnO₂@SiNWs composite was systematically investigated. Structural characterization through X-ray diffraction (XRD) and surface analysis via X-ray photoelectron spectroscopy (XPS) confirmed the successful formation of the hybrid oxide network. Furthermore, scanning electron microscopy (SEM) revealed a homogeneous distribution of the nanostructured composite coating over the vertically aligned SiNWs, forming a porous, interconnected network favorable for ion diffusion. Energy-dispersive X-ray spectroscopy (EDX) mapping confirmed the uniform presence of W, Mn, O, and Si elements throughout the electrode, indicating successful and consistent deposition of the WO₃-MnO₂ layers. The optimized electrode exhibited excellent capacitive performance, delivering a specific capacitance (Csp) of 16.56 mF·cm−2, an energy density (Ed) of 0.0001 Wh·cm−2, and a power density (Pd) of 0.024 W·cm−2, along with long-term cycling stability retaining 84 % of its initial capacitance over 4000 charge–discharge cycles. Additionally, electrochemical impedance spectroscopy revealed a consistent Csp of 14.23 mF·cm−2over a wide frequency range (0.01 Hz–1 MHz), indicating efficient charge transfer and low internal resistance. A solid-state symmetric μSC device constructed using WO₃-MnO₂@SiNWs electrodes further demonstrated impressive performance, achieving a maximum specific capacitance of 96 mF·cm−2at a scan rate of 2 mV·s−1, with 85 % capacitance retention over 2300 cycles and an energy density of 0.0028 Wh·cm−2at a power density of 0.4 W·cm−2. These remarkable electrochemical properties are attributed to the synergistic effects of multivalent WO₃ and MnO₂ species combined with the high conductivity and mechanical stability of the SiNWs framework, highlighting the potential of this composite architecture for next-generation on-chip energy storage devices.
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    Modification of diss fibers for biocomposites based on recycled Low-Density polyethylene and polypropylene blends
    (Springer, 2019) Touati, Zohra; Boulahia, Hakima; Belhaneche-Bensemra, Naima; Massardier, Valérie
    The aim of this work is the valorization of diss fibers with recycled and regenerated low-density polyethylene (rLDPE) for the development of biocomposites based on blends of rLDPE polypropylene (PP) and diss fibers. The diss fibers were characterized by laser granulometer and FTIR spectroscopy. Two PP/rLDPE blends of different compositions (50/50 and 75/25) were prepared. These polymer blends were reinforced by nano-Si particles and compatibilizers which were investigated using three compatibilizers: maleic anhydride functionalized ethylene copolymer rubber (MAC), maleic anhydride functionalized ethylene copolymer rubber/SiO2 (MAC/SiO2), and maleic anhydride functionalized ethylene copolymer rubber/SiO2/ionic liquid (MAC/SiO2/IL). The thermal properties of the blends were studied using differential scanning calorimetry and thermogravimetric analysis. Their crystallinity was investigated by X-ray diffraction and their morphology by scanning electron microscopy, while mechanical properties were evaluated by tensile testing. The best tensile properties were obtained for the PP/rLDPE (75/25) blend. A significant increase of the Young’s modulus, stress at break, and elongation at break was obtained with the three compatibilizers. MAC acted as a compatibilizer of both polymers, resulting in improved interfacial adhesion which increased tensile properties. Finally, the effect of diss fiber surface modification on the properties of PP/rLDPE blends was considered. The results showed a modification of tensile properties and a satisfactory interfacial adhesion between diss fibers and polymer blends. Furthermore, thermal stability was not significantly decreased by the addition of 5 wt% diss fibers
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    Valorization of waste jute fibers in developing low-density polyethylene /poly lactic acid bio-based composites
    (SAGE, 2015) Boubekeur, Bahia; Belhaneche-Bensemra, Naima; Massardier, Valérie
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    Mechanical characterizations of composite material with short Alfa fibers reinforcement
    (Elsevier, 2015) Mechakra, Hamza; Nour, Abdelkader; Lecheb, Samir; Chellil, Ahmed
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    Laminate reinforced with natural fibers of dwarf palm tree (Doum)
    (2009) Amer, M.; Tahar Kamal, A.I.T.; Boukais, S.; Bouamra, Y.
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    Biodegradables composites : prepration and characterization
    (2009) Boumerdassi, K.; Serier, A.; Timhadjelt, L.
    This study focuses on the polystyrene matrix composites and micro loads of vegetable origin: spruce sawdust and celelulose microcrystal. The latter are obtained by extracting the cellulose from flour spruce. The composite samples were prepared by injection. The particle size analysis made it possible to determine the size of the charges and to highlight the effectiveness of treatment extraction. Analysis of microstructural changes was followed by Fourier transform inefrared spectroscopy and morphology by scanning electron microscopy. The mechanical behaviour and tensile strength were studied before and after hydrothermal aging