Starch-assisted Electrochemical Synthesis of Uniform Cobalt Hydroxide Nanoplates as High Performance Electrode Material for Supercapacitors

Two-dimensional nanoplates or nanosheets possess interesting properties because of their high anisotropy and ultra-thickness [1]. Nanoplates are considered as ideal systems for the investigation of dimensionally confined transport phenomena and as the ideal bases upon which to build functional devices [2]. Therefore, it would be interesting to develop new methods for the synthesis of nanoplates of a variety of compounds. Co(OH)2 materials have been attractive in view of their layered structure with large interlayer spacing, their well-defined electrochemical redox activity, and the possibility of enhanced performance through different preparative methods. An emerging application of Co(OH)2 is an electrode material for electrochemical supercapacitors [3]. In this research, cathodic electrodeposition of cobalt hydroxide was performed in the presence of starch. The prepared sample was characterized through XRD, IR, DSC-TGA, SEM and cyclic voltammetry. The analyses results revealed that the deposited hydroxide has pure crystalline β cobalt hydroxide composition with uniform hexagonal plate morphology at nanoscale (Figs. 1a and b). The supercapacitive performance of the prepared nanoplates was also investigated by cyclic voltammetry (CV) as shown in Figs. 1c and d. The results showed that the prepared β-Co(OH)2 nanoplates exhibit excellent charge storage ability (SC= 1015 F g–1 at the scan rate of 5 mV s–1). 242