Ultra-rapid chemical synthesis of mesoporous Bi2O3 micro-sponge-balls for supercapattery applications

Polycrystalline and mesoporous bismuth oxide (Bi2O3) micro-sponge-balls of 4-7 mu m 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 degrees 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. (C) 2018 Elsevier Ltd. All rights reserved.