Enhanced Charge Transfer and Energy Storage Performance of Ni/Co–WO3 Nanostructures for DSSC and Supercapacitor Applications
摘要
There is a significant need in the current energy conversion and storage systems for multifunctional electrode materials that possess exceptional photovoltaic and electrochemical properties. This study synthesizes WO3 and Ni/Co co-doped WO3 nanostructures using a hydrothermal approach. Then, their properties for dye-sensitized solar cells and asymmetric supercapacitors are evaluated. WO3 has enhanced electron transit, resistance to charge recombination, and capacity for efficient charge collection make it a promising material for photoelectrodes. Energy storage applications are well suited to its reversible redox activity and pseudocapacitive properties. Structural analysis confirmed the formation of monoclinic WO3 without impurity phases, whereas morphological studies revealed uniformly distributed spherical nanoparticles with improved interparticle connectivity after Ni/Co co-doping. The Ni/Co co-doped WO3 sample showed improved visible light absorption with a simultaneous drop of the band-gap energy from 2.34 to 2.19 eV and decreased charge-carrier recombination. The Ni/Co–WO3-based device achieved a power conversion efficiency of 8.95%, exceeding those of pristine WO3 (3.55%) and Pt-based devices (7.20%), while retaining ~ 91% of its initial efficiency after 100 days. Electrochemical measurements revealed a high specific capacitance of 1333 F g−1 at 1 A g−1. The built asymmetric supercapacitor showed an energy density of 35.1 Wh kg−1 at a power density of 845 W kg−1 with a capacitance retention of 97% after 5000 cycles, which demonstrates the positive effect of Ni/Co inclusion in charge storage and transfer. These findings demonstrate the potential of Ni/Co–WO3 nanostructures as promising multifunctional materials for next-generation energy conversion and storage technologies.