One-step electrodeposited Co and Mn layered double hydroxides on Ni foam for high-performance aqueous asymmetric supercapacitors

In this work, we report a high-performance and self-standing supercapacitor electrode composed of a Co and Mn layered double hydroxide (CoMn-LDH) nanostructure on Ni foam (NF) prepared by one-step electrochemical deposition. The CoMn-LDH electrode delivers a high capacitance of-2673.6 F g(-1) at 1 A g(-1), with the excellent rate performance (-1488.0 F g(-1) at 60 A g(-1)) and good cycle stability (-86.7% capacitance retention after 5000 cycles at 12 A g(-1)). The asymmetric supercapacitors assembled using the cathode of CoMn-LDH, the anode of activated carbon on carbon cloth and the electrolyte of 2.0 M KOH yield an energy density of-97.5 W h kg(-1) at 800.0 W kg(-1), good cycling performance of-89.2% capacitance retention after 5000 cycles at 5 A g(-1) with the Columbic efficiency around 100%. These results indicate that the CoMn-LDH nanostructure on NF is a promising electrode for high-performance energy storage applications.