Electrochemical deposition of Indium(III) hydroxide nanostructures for novel battery-like capacitive materials

Abstract

In the last decades, the metal hydroxide-based battery-like supercapacitors have more attracted researchers interest due to their superior power density, unique reversibility, and low-cost. Herein, we synthesized Indium(III) hydroxide (In(OH)3) nanostructures by a one-step electrochemical deposition technique and reported the supercapacitor properties for the first time in the literature to propose an alternative active material for the metal hydroxide-based battery-like supercapacitors. The X-ray powder diffraction spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and Brunauer-Emmett-Teller method were used to realize the analytical and morphological characterizations. The reported supercapacitor and electrochemical properties of In(OH)3 nanostructures were obtained through cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy in an aqueous 3 M KOH electrolyte. The electrodeposited In(OH)3 nanostructures exhibit a good specific capacitance of 271.4, 226.4, 192.6, 167.3, 149.2 F g−1 at 1, 2, 4, 8, 20 A g−1, respectively and acceptable cycling stability with capacitance loss of 27.7% after 10,000 cycles at 4 A g−1. Moreover, the designed symmetric supercapacitor based on fluorine doped tin oxide (FTO)-In(OH)3 electrodes offers a good capacitive performance (167.6 F g−1 at a low current density of 1 A g−1 and 67.36 F g−1 at a higher current density of 8 A g−1), cycling stability (80.2% retention after 2000 cycles at 4 A g−1), and a maximum energy density of 23.3 Wh kg−1 at a power density of 499.9 W kg−1. The results compared with previously reported other metal hydroxides are promising a novel battery-like capacitive material for energy storage devices as metal hydroxide-based battery-like supercapacitors.