Sea urchin-like Pr-doped W18O49 nanospheres for high-performance supercapacitors

Exploring high-performance metal oxide electrode materials is an essential way to boost the supercapacitor performance, and metal atom doping can significantly increase oxygen vacancies to improve the conductivity of electrode materials. A hydrothermal method is proposed for the preparation of sea urchin-like Pr-doped W 18 O 49 . A series of characterizations detected that Pr-doped W 18 O 49 produced significant lattice distortion and more amorphous regions, and the better electrochemical performance came from the increased concentration of oxygen vacancies, enlarged lattice spacing, higher specific surface area, and faster ion transport after Pr doping. Electrochemical measurements indicate that the specific capacitance of Pr-doped W 18 O 49 is improved from 381 F g −1 to 453 F g −1 at 3 A g −1 and exhibits a remarkable capacity retention of 95.6 % over 4000 cycles. An asymmetric supercapacitor assembled with this electrode and PPy achieved a high energy density of 21.9 Wh kg −1 at a power density of 701.5 W kg −1 , indicating the significance of Pr-doped W 18 O 49 for energy conversion and storage applications.