Morphology controlled synthesis of monodisperse cobalt hydroxide for supercapacitor with high performance and long cycle life

• Published in: Journal of power sources Vol. 256; pp. 160 - 169
• Main Authors: Tang, Yongfu, Liu, Yanyan, Yu, Shengxue, Mu, Shichun, Xiao, Shaohua, Zhao, Yufeng, Gao, Faming
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.06.2014; Elsevier
• Subjects: Applied sciences; Asymmetric supercapacitor; Capacitance; Capacitors; Capacitors. Resistors. Filters; Cobalt; Cobalt hydroxide; Cubic nanocrystal; Density; Electrical engineering. Electrical power engineering; Exact sciences and technology; Hydroxides; Morphology; Nanowire; Nanowires; Supercapacitor; Supercapacitors; Various equipment and components; Supercapacitor; Nanowire; Cobalt hydroxide; Asymmetric supercapacitor; Cubic nanocrystal; High performance; Electrolytic capacitor; Lifetime; Cobalt Hydroxides; Morphology; Nanowires; Chemical synthesis; Nanocrystal
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2014.01.064

A facile hydrothermal process with hexadecyltrimethyl ammonium bromide (CTAB) as the soft template is proposed to tune the morphology and size of cobalt hydroxide (Co(OH)2). Monodisperse β-phase Co(OH)2 nanowires with uniform size are obtained by controlling the CTAB content and the reaction time. Due to the uniform well-defined morphology and stable structure, the Co(OH)2 nanowires material exhibits high capacitive performance and long cycle life. The specific capacitance of the Co(OH)2 nanowires electrode is 358 F g−1 at 0.5 A g−1, and even 325 F g−1 at 10 A g−1. The specific capacitance retention is 86.3% after 5000 charge–discharge cycles at 2 A g−1. Moreover, the asymmetric supercapacitor is assembled with Co(OH)2 nanowires and nitrite acid treated activated carbon (NTAC), which shows an energy density of 13.6 Wh kg−1 at the power density of 153 W kg−1 under a high voltage of 1.6 V, and 13.1 Wh kg−1 even at the power density of 1.88 kW kg−1. [Display omitted] •Monodisperse cobalt hydroxide nanocubes and nanowires are synthesized.•Morphology and size of Co(OH)2 are tuned by CTAB content and reaction time.•Co(OH)2 nanowires electrode exhibits high performance and long cycle life.•As-prepared asymmetric supercapacitor shows high voltage and energy density.