RESUMO
Design and fabrication of novel electrode materials with excellent specific capacitance and cycle stability are urgent for advanced energy storage devices, and the combinability of multiple modification methods is still insufficient. Herein, Ni2+, Zn2+ double-cation-substitution Co carbonate hydroxide (NiZnCo-CH) nanosheets arrays were established on 3D copper with controllable morphology (3DCu@NiZnCo-CH). The self-standing scalable dendritic copper offers a large surface area and promotes fast electron transport. The 3DCu@NiZnCo-CH electrode shows a markedly improved electrochemical performance with a high specific capacity of â¼1008 C g-1 at 1 A g-1 (3.2, 2.83, and 1.26 times larger than Co-CH, ZnCo-CH, and NiCo-CH, respectively) and outstanding rate capability (828.8 C g-1 at 20 A g-1) due to its compositional and structural advantages. Density functional theory (DFT) calculation results illustrate that cation doping adjusts the adsorption process and optimizes the charge transfer kinetics. Moreover, an aqueous hybrid supercapacitor based on 3DCu@NiZnCo-CH and rGO demonstrates a high energy density of 42.29 Wh kg-1 at a power density of 376.37 W kg-1, along with superior cycling performance (retained 86.7% of the initial specific capacitance after 10,000 cycles). Impressively, these optimized 3DCu@NiZnCo-CH//rGO devices with ionic liquid can be operated stably in a large potential range of 4 V with greatly enhanced energy density and power capability (110.12 Wh kg-1 at a power density of 71.69 W kg-1). These findings may shed some light on the rational design of transition-metal compounds with tunable architectures by multiple modification methods for efficient energy storage.
RESUMO
In this study we report on the electrodeposition of copper thiocynate (CuSCN) nanorod arrays on ITO substrate from an EDTA-chelated aqueous solution. Effects of molecule ratio of EDTA/Cu²âº and deposition time on the properties of CuSCN layers were studied. Results showed that films deposited from an electrolyte with low EDTA amounts were consisted of densely packed nano-crystals, while films deposited with high molecule ratios of EDTA/Cu²âº (>0.5) were composed of homogeneous nanorods with their (001) plane perpendicular to the substrate. Further time-dependent study showed that the formation of CuSCN nanorods was initiated at the very beginning of potential application and no intermediate or transitional products were detected during the electrochemical process. Optical analysis showed that films of CuSCN nanorods with a thickness of 100400 nm had good optical quality, and exhibited the fundamental absorption edge at 320 nm.