Facile preparation of flower-like NiMn layered double hydroxide/reduced graphene oxide microsphere composite for high-performance asymmetric supercapacitors

NiMn layered double hydroxide (NiMn LDH) and NiMn LDH/reduced graphene oxide (rGO) with flower-like 3D composite were synthesized by a simple solvothermal process. The electrochemical properties of NiMn LDH/rGO composite with different contents of rGO were studied, resulting in enhanced capacitance due to the incorporation of rGO compared with pristine NiMn LDH. The NiMn LDH/rGO composite containing 4.46 wt% rGO (LDH/rGO-4) exhibited the highest specific capacitance of 1500 F g −1  at 1 A g −1 with an excellent cyclic stability of 90.5% over 5000 charging and discharging cycles at 20 A g −1 . The asymmetric supercapacitor assembled with LDH/rGO-4 and rGO electrodes exhibited a high specific capacitance of 82.5 F g −1  at 0.5 A g −1 and superior energy density of 29.3 Wh kg −1 . These results illustrate that the LDH/rGO-4 composite is a promising material for supercapacitor applications.