Flexible Ce-doped WO₃ nanowire arrays with enriched oxygen vacancies for soft-packaged asymmetric supercapacitor

Tungsten trioxide (WO₃) is recognized as a promising anode material for asymmetric supercapacitors (ASCs), yet its low conductivity and stability as well as energy density greatly limit its development. Herein, a flexible Ce-doped WO₃ (Ce_1.5%-WO₃) nanowire array with rich oxygen vacancies is grown on carbon cloth by a solvothermal synthesis. The specific capacitance of Ce_1.5%-WO₃ is 493F g⁻¹ at 4 A/g and remains 90.4 % after 5000 cycles, superior to that of WO₃ nanowire arrays (416F g⁻¹, 80.3 %). The improved performance mainly stems from the synergistic effects of more oxygen vacancies, higher specific surface area, wider lattice spacing, faster ion diffusion, and electron transport generated by Ce doping. As-prepared ASC device can reach an energy density of 31.7 Wh kg⁻¹ at a power density of 700 W kg⁻¹. Furthermore, two flexible soft-packaged ASCs connected in series can illuminate different electronic devices. This strategy proves the great application prospect of Ce-doped WO₃ nanowire arrays flexible electrodes in supercapacitors.