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Highlights: A novel method is developed for precise control over the structure of 3D anodic aluminum oxide templates, enabling fine-tuning of both the vertical pore diameter and interspace within the templates. 3D carbon tube nanoarrays featuring significantly thinner and denser tubes are constructed as high-quality electrodes for miniaturized filter capacitors. The 3D compactly arranged carbon tube-based capacitor achieves a remarkable specific areal capacitance of 3.23 mF cm−2 with a phase angle of − 80.2° at 120 Hz. Electric double-layer capacitors (EDLCs) with fast frequency response are regarded as small-scale alternatives to the commercial bulky aluminum electrolytic capacitors. Creating carbon-based nanoarray electrodes with precise alignment and smooth ion channels is crucial for enhancing EDLCs' performance. However, controlling the density of macropore-dominated nanoarray electrodes poses challenges in boosting the capacitance of line-filtering EDLCs. Herein, a simple technique to finely adjust the vertical-pore diameter and inter-spacing in three-dimensional nanoporous anodic aluminum oxide (3D-AAO) template is achieved, and 3D compactly arranged carbon tube (3D-CACT) nanoarrays are created as electrodes for symmetrical EDLCs using nanoporous 3D-AAO template-assisted chemical vapor deposition of carbon. The 3D-CACT electrodes demonstrate a high surface area of 253.0 m2 g−1, a D/G band intensity ratio of 0.94, and a C/O atomic ratio of 8. As a result, the high-density 3D-CT nanoarray-based sandwich-type EDLCs demonstrate a record high specific areal capacitance of 3.23 mF cm−2 at 120 Hz and exceptional fast frequency response due to the vertically aligned and highly ordered nanoarray of closely packed CT units. The 3D-CT nanoarray electrode-based EDLCs could serve as line filters in integrated circuits, aiding power system miniaturization. [ABSTRACT FROM AUTHOR]

Heterogeneous microstructural design has been proven to be an effective strategy in breaking the strength–ductility dilemma in nanostructured metals. However, the precise control of heterogeneous microstructures to achieve strength–ductility synergy remains challenging. Here, we demonstrate a novel powder metallurgy approach for creating three-dimensional (3D) core–shell nanostructures with highly tunable shell thickness and grain size distributions. These 3D nanostructures enable superior strength–ductility synergy in pure copper, pushing the boundary of the Ashby map to unchartered territory. A combination of microstructural characterization, atomistic simulations and crystal plasticity modeling reveals that the generation and accumulation of geometrically necessary dislocations near the core–shell interface play a pivotal role in accommodating the strain gradient and sustaining a high strain-hardening rate during plastic deformation. Our work provides a viable approach for designing bulk nanostructured materials with 3D heterogeneous ingredients and demonstrates a promising pathway for the development of strong and ductile materials. [Display omitted] [ABSTRACT FROM AUTHOR]