Abstract
Polycrystalline and mesoporous bismuth oxide (Bi2O3) micro-sponge-balls of 4–7 μm in diameter comprising of 58–65 (±2) nm upright standing petals, separated by 100–700 (±50) nm crevices, are synthesized directly onto 3D Ni-foam at room-temperature (27 °C) using Tritonx-100 surfactant-mediated soft wet chemical method. After knowing the phase purity, surface area, pore-size distribution, micro-sponge-ball-type surface morphology, elemental analysis and binding energy confirmations of Bi2O3, a material with quasi-faradaic redox reactions responsible for supercapattery type behavior, are measured and explored. At a low scan rate, the specific capacitance of Bi2O3 sponge-ball electrode, measured from 0.4 to 1.80 A g−1 current density, decreases from 559 to 211 F g−1 which is equivalent to a capacity from 155 to 58 mAh.g−1. An asymmetric supercapacitor (ASC) device assembly of Bi2O3 sponge-ball electrode with graphite i.e. Bi2O3//graphite demonstrates excellent electrochemical properties with 8 Wh kg−1 energy density at 2040 W kg−1 power density, and about 80% cycling retention over 5000 redox cycle operations. A demonstration of LED with full-bright intensity during discharge process of the Bi2O3//graphite ASC device suggests its practical potentiality and industrial viability.
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