Design binder-free Ni0.66Co0.34-LDH heterostructures as electrode material for supercapacitor application

Hierarchical Ni 0.66 Co 0.34 -LDH heterostructures are designed as electrode materials in this work. The ultrathin Ni 0.66 Co 0.34 -LDH nanosheets are decorated uniformly on Cu(OH) 2 nanowire backbones, providing richness active sites, open ion channel, and conductive- and binder-free heterostructure for electrochemical energy storage . At the current density of 5 ​mA ​cm −2 , the as-prepared Ni 0.66 Co 0.34 -LDH heterostructure electrode displays a specific capacitance of 17740 ​mF ​cm −2 (2367.3 ​F ​g −1 ), higher than that of Ni–Co LDH directly deposited on copper foam substrate (1390 ​mF ​cm −2 ). Additionally, an excellent rate capability (13880 ​mF ​cm −2 vs 20 ​mA ​cm −2 ) and remarkable cycling stability (88.9% vs 10 ​000 cycles) are obtained. Furthermore, the maximum energy density can arrive to 0.813 ​mWh cm −2 (power density of 8 ​mW ​cm −2 for the assembled solid-state Cu(OH) 2 @Ni 0.66 Co 0.34 -LDH//AC asymmetric cell. These prominent performances might be aroused by its special hierarchical core/shell heterostructures. These findings properly promote the design novel nanostructures for the advanced electrodes.