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 (Ce1.5%-WO3) nanowire array with rich oxygen vacancies is grown on carbon cloth by a solvothermal synthesis. The specific capacitance of Ce1.5%-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.