Hierarchical coral-like MnCo 2 O 4.5 @Co–Ni LDH composites on Ni foam as promising electrodes for high-performance supercapacitor

Transition metal oxides are generally designed as hybrid nanostructures with high performance for supercapacitors by enjoying the advantages of various electroactive materials. In this paper, a convenient and efficient route had been proposed to prepare hierarchical coral-like MnCo 2 O 4.5 @Co–Ni LDH composites on Ni foam, in which MnCo 2 O 4.5 nanowires were enlaced with ultrathin Co–Ni layered double hydroxides nanosheets to achieve high capacity electrodes for supercapacitors. Due to the synergistic effect of shell Co–Ni LDH and core MnCo 2 O 4.5 , the outstanding electrochemical performance in three-electrode configuration was triggered (high area capacitance of 5.08 F cm −2 at 3 mA cm −2 and excellent rate capability of maintaining 61.69% at 20 mA cm −2 ), which is superior to those of MnCo 2 O 4.5 , Co–Ni LDH and other metal oxides based composites reported. Meanwhile, the as-prepared hierarchical MnCo 2 O 4.5 @Co–Ni LDH electrode delivered improved electrical conductivity than that of pristine MnCo 2 O 4.5 . Furthermore, the as-constructed asymmetric supercapacitor using MnCo 2 O 4.5 @Co–Ni LDH as positive and activated carbon as negative electrode presented a rather high energy density of 220 μ Wh cm −2 at 2400 μ W cm −2 and extraordinary cycling durability with the 100.0% capacitance retention over 8000 cycles at 20 mA cm −2 , demonstrating the best electrochemical performance compared to other asymmetric supercapacitors using metal oxides based composites as positive electrode material. It can be expected that the obtained MnCo 2 O 4.5 @Co–Ni LDH could be used as the high performance and cost-effective electrode in supercapacitors.