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In this study, a 3D-prinited solution-flow type microdroplet cell (SF-MDC) is employed as a new technique for the fabrication of porous anodic aluminum oxide (AAO) layer using oxalic acid electrolyte on aluminum. The surface morphology of the porous AAO film was characterized by a scanning electron microscope. The aim of this study was to fabricate a through-hole porous alumina layer in a single step anodizing process and to investigate the influence of anodized voltages and scanning speeds on the thickness and pore structure of alumina layer. The results showed that the pore diameter and interpore distance were directly proportional to the anodizing voltage. The thicknesses of formed AAO films were found to be 35.5, 50.7, and 81.6 μm at scanning speeds of 10, 5, and 2.5 μms−1, respectively. Through-hole porous AAO was successfully fabricated at room temperature without chemical etching. The SF-MDC fabrication technique is proposed as an environmentally attractive and suitable process for the fabrication of porous AAO layers.

In this work, an attempt has been made to synthesize a novel heterostructure nanocomposite, C/Ru@NiO-CuO (CRNC) which is suitable for energy storage application. It was chemically synthesized at high-temperature conditions, whose structural features and surface chemistry were characterized by various analytical tools. The CRNC nanocomposite reveals the nanospherical morphology with highly crystalline heterostructure, leading to reliable electrode material-preferred advantages such as good conductivity, high-surface area, and numerous oxidation states for supercapacitor (SC) applications. Composition of high conductivity of carbon and high chemical stability of ternary metal oxides, a heterostructure CRNC electrode is proposed for effective solid-state symmetric and asymmetric battery-type SC. The as-prepared CRNC shows an excellent electrochemical performance at 0.5 A g–1in a three-electrode cell configuration, where the specific capacitance value obtained was 318 F g–1. Having the completion of 5000 galvanostatic charge–discharge (GCD) cycles, the electrode can hold a good capacity retention (86.7%). A solid-state asymmetric supercapacitor (ASC) was constructed by placing the separator between the CRNC and rGO/α-Co3O4, which delivers a specific capacitance of 152.5 F g–1(at 0.5 A g–1) along with 87% capacitance retention after 3500 GCD cycles. Furthermore, the ASC offers energy and power density values as 21.18 W h kg–1and 1800 W kg–1, respectively. The novel CRNC//rGO/α-Co3O4construction implies a good structural stability, long-term cycle stability, very good rate capability, and favorable compatibility. This study reveals that carbon-embedded Ru-doped NiO-CuO nanocomposite electrode exhibits better electrochemical behavior due to the high synergistic effect of ternary metal oxide compared with bimetal oxide. To improve the practical applicability of ASC device, we assembled the device for better flexibility, also demonstrating the extensive advantages and accessibility.