Asymmetric supercapacitors with excellent rate performance by integrating Co(OH)F nanorods and layered Ti3C2Tx paper

Abstract

Here we describe an aqueous asymmetric supercapacitor assembled using Co(OH)F nanorods on Ni foam (Co(OH)F@NF) as the positive electrode and layered Ti₃C₂T_x paper on Ni foam (Ti₃C₂T_x@NF) as the negative electrode. The Co(OH)F@NF was fabricated by a facile hydrothermal process. The nanorods were constructed as three-dimensional networks with stable structures and good durability in electrochemical reactions. As expected, the Co(OH)F@NF exhibited excellent capacitance (1265 mF cm⁻² at 1 mA cm⁻²) and wonderful rate performance (90% from 1 to 10 mA cm⁻²). The Co(OH)F@NF//Ti₃C₂T_x@NF asymmetric supercapacitor devices showed high capacitance of 376 mF cm⁻² and excellent rate capacity of 91% retention. When the two Co(OH)F@NF//Ti₃C₂T_x@NF devices were combined in series, a red led bulb could be lit for 12 minutes, further corroborating the possibility of the devices being used for practical applications.