Supercritical ethanol deposition of Ni(OH)2 nanosheets on carbon cloth for flexible solid-state asymmetric supercapacitor electrode

Ni(OH)(2) nanosheets (NSs) were grown onto an electrochemically activated carbon cloth (ECC) with a self-supported microstructure by using efficient ethanol assisted supercritical deposition method. Benefited from the structural features of the well-developed porous architecture with effective channels for electrolyte ions diffusion and accessible redox sites, the nano-heterostructure brings a high utilization of electroactive material and thereby good electrochemical performance. The specific capacity of 918 mC cm(-2) at 2 mA cm(-2) with good rate performance (68.4 % retention at 20 mA cm(-2)) was achieved for the obtained Ni(OH)(2) NSs/ECC flexible electrode. The assembled flexible solid-state device with a 1.8 V operating potential displays an energy density of 8.3 mW h cm(-3) at 20 mW cm(-3). Additionally, the asfabricated device reveals cyclic stability with 87 % capacity retention (10,000 cycles at 50 mA cm(-2)). These results show the importance of supercritical fluid deposition as a potential method for supercapacitors electrode. (C) 2020 Published by Elsevier B.V.