Effectively morphology-controlled NiMn layered double hydroxide microflowers by conductive silver nanowires for supercapacitor electrodes

Abstract

Effective ion and electron transport pathways provide an effective method to further improve the energy storage performance of layered double hydroxide (LDH) for supercapacitors. Here, microflower-like NiMn LDH/silver nanowires (Ag NWs) composites for high-performance supercapacitors are constructed by a convenient hydrothermal method, in which silver nanowires are found to not only ensure excellent electron conductivity but also have a positive effect on the growth of LDH nanosheets to form the unique three-dimensional open pore structure. In addition, the significantly increased interlayer spacing of the composite enables fast ion transport. In particular, NiMn LDH/Ag NWs exhibits higher specific capacitance (1436.30 F·g−1 at 2 A·g−1) in a three-electrode system, which is 121.29% of the specific capacitance of pure NiMn LDH. The asymmetric supercapacitor assembled with NiMn LDH/Ag NWs and AC electrode exhibits high specific capacitance of 215.63 F·g−1 at 2 A·g−1, superior energy density of 71.95 Wh·kg−1 and excellent cycling stability, illustrating that the NiMn LDH/Ag NWs composite is the promising material for supercapacitor applications.