High-power and long-life supercapacitive performance of hierarchical, 3-D urchin-like W₁₈O₄₉ nanostructure electrodes

We report the facile, one-pot synthesis of 3-D urchin-like W₁₈O₄₉ nanostructures (U-WO) via a simple solvothermal approach. An excellent supercapacitive performance was achieved by the U-WO because of its large Brunauer–Emmett–Teller (BET) specific surface area (ca. 123 m²·g^–1) and unique morphological and structural features. The U-WO electrodes not only exhibit a high rate-capability with a specific capacitance (Csp) of ~235 F·g^–1 at a current density of 20 A·g^–1, but also superior long-life performance for 1, 000 cycles, and even up to 7, 000 cycles, showing ~176 F·g^–1 at a high current density of 40 A·g^–1.