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.