CdS nanosheets as electrode materials for all pseudocapacitive asymmetric supercapacitors

Metal sulphides have recently been explored as a very promising pseudocapacitor electrode, owing to their unique physical, electronic and electrochemical properties. This study reports the synthesis and pseudocapacitor applications of 2D cadmium sulphide (CdS) nanosheets deposited on Ni foam via electrophoretic deposition method. Comprehensive morphological and electrochemical analyses were performed to elucidate the correlation between the structural features of CdS and their charge storage properties. The single electrode characterizations of CdS could exhibit a specific capacitance as high as 1165 F g–1 at 2 mV s–1. An asymmetric supercapacitor prototype was also fabricated using the CdS nanosheets with ceria–titania nanotube composite (CeO2–TNT) counter electrode. The device could exhibit an energy density as high as 14.58 Wh kg–1 at a power density of 1.9 kW kg–1. At the end of 2000 cycles, the device could retain 100% of its initial capacitance.