Résumé
Advanced energy storage technologies, such as rechargeable Batteries and Micro-supercapacitors (mu SCs) 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-MnO2composite 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-MnO2layers. The optimized electrode exhibited excellent capacitive performance, delivering a specific capacitance (Csp) of 16.56 mF & sdot;cm-2, an energy density (Ed) of 0.0001 Wh & sdot;cm-2, and a power density (Pd) of 0.024 W & sdot;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 & sdot;cm-2 over a wide frequency range (0.01 Hz-1 MHz), indicating efficient charge transfer and low internal resistance. A solid-state symmetric mu SC device constructed using WO3-MnO2@SiNWs electrodes further demonstrated impressive performance, achieving a maximum specific capacitance of 96 mF & sdot;cm-2 at a scan rate of 2 mV & sdot;s-1, with 85 % capacitance retention over 2300 cycles and an energy density of 0.0028 Wh & sdot;cm-2 at a power density of 0.4 W & sdot;cm-2. These remarkable electrochemical properties are attributed to the synergistic effects of multivalent WO3 and MnO2species 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.