Jizhang Chen

Facile and scalable fabrication of three-dimensional Cu(OH)2 nanoporous nanorods for solid-state supercapacitors

A facile and scalable one-step anodization method has been developed to fabricate three-dimensional (3-D) Cu(OH)2 nanoporous nanorods on a copper foil substrate, a product that can be used directly as a binder-free electrode for supercapacitors. The unique morphology of the nanorods provides a large amount of active sites for redox reactions, which can be easily accessed by electrolyte ions. Benefiting from that, a high capacitance of 213 mF cm−2 is obtained, and superior rate capability (62.3% capacitance retention when the scan rate is increased to 10 times) and excellent cyclability (92.0% capacitance retention after 5000 cycles) are achieved. In addition, a flexible and foldable solid-state asymmetric supercapacitor is assembled using the Cu(OH)2 and activated carbon as the positive and negative electrodes, respectively. The devices deliver a high energy density of 3.68 mW h cm−3 and a high power density of 5314 mW cm−3, demonstrating great potential for next-generation high-rate energy storage systems.

Hybridizing Fe3O4 nanocrystals with nitrogen-doped carbon nanowires for high-performance supercapacitors

This study develops a facile approach to anchor Fe3O4 nanocrystals uniformly onto nitrogen-doped carbon nanowires (NCN). The influence of the ratio of Fe3O4 to NCN on the structure and pseudocapacitance performance of the nanocomposite is investigated systematically. It is found that the best performance is realized when the mass percentage of Fe3O4 is 65.9%. Benefiting from the synergistic effect of the nanostructure and conductive matrix, the optimized nanocomposite delivers high specific capacitance (541.7 F g−1 at 1 A g−1), superior rate capability (337.1 F g−1 at 10 A g−1), as well as good cyclability. This nanocomposite is also used as the anode material for assembling an asymmetric supercapacitor, which exhibits a high specific energy of 59.1 W h kg−1 and high specific power of 17.85 kW kg−1. The results manifest the great potential of this nanocomposite for next-generation high-power applications.