Preparation and characterization of CdSe as electrode materials for supercapacitors

This paper reports an electrochemical supercapacitor with CdSe electrode synthesized by a simple and economical electrodeposition method. The purpose of setting the deposition time from 20 to 50 min is to study the influence of deposition time on the electrochemical performance of CdSe electrodes. The synthesis of CdSe was confirmed by a few characterization techniques, such as scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The electrochemical properties of the CdSe were estimated by galvanostatic charge-discharge, electrochemical impedance and cyclic voltammetry. It was proved that the best electrochemical performance of the CdSe electrode deposited for 40 min. The as-prepared CdSe electrodes (40 min) exhibited a high specific capacitance of 1542 mF/cm 2 at 1 mA/cm 2 . The capacitance retention of CdSe (40 min) after 1000 cycles remains 78.9 % at 3 mA/cm 2 . Moreover, the symmetrical aqueous supercapacitor and a symmetrical solid-state supercapacitor were assembled with CdSe (40 min) electrodes, respectively. The two capacitors of the same type in series can light up the LED, indicating that CdSe has a certain practical application in energy storage. In this paper, condensed spherical CdSe has been successfully synthesized, and symmetric aqueous capacitor and symmetric solid-state capacitor were assembled. The devices have good cycling stability and coulomb efficiency. Two capacitors of the same type are connected in series to light up a red LED bulb for several seconds. In addition, the capacitors assembled here have high energy density and power density. • Agglomerated spherical CdSe was prepared by the electrochemical deposition method. • The specific capacitance of CdSe single electrode was 1542 mF/cm 2 at 1 mA/cm 2 . • Symmetrical solid and aqueous supercapacitors were assembled and light up the LEDs.