Herein, a general strategy is proposed to boost the energy storage capability of pseudocapacitive materials (i.e., MnO2) to their theoretical limits in unconventional 1D fiber configuration by rationally designing bicontinuous porous Ni skeleton@metal wire “sheath–core” metallic scaffold as a versatile host. As a proof of concept, the 1D metallic scaffold supported-MnO2 fiber electrode is demonstrated. The proposed “sheath” design not only affords large electrode surface area with ordered macropores for large electrolyte-ion accessibility and high electroactive material loading, but also renders interconnected porous metallic skeleton for efficient electronic and ionic transport, while the metallic “core” functions as an extra current collector to promote long-distance electron transport and electron collection. Benefiting from all these merits, the optimized fiber electrode yields unprecedented specific areal capacitance of 1303.6 mF cm−2 (1278 F g−1 based on MnO2, approaching the theoretical value of 1370 F g−1) in liquid KOH and 847.22 mF cm−2 in polyvinyl alcohol (PVA)/KOH gel electrolyte, 2–350 times of previously reported fiber electrodes. The solid-state fiber micro-pseudocapacitors simultaneously achieve remarkable areal energy and power densities of 18.83 µWh cm−2 and 16.33 mW cm−2, greatly exceeding the existing symmetric fiber supercapacitors, together with long cycle life and high rate capability.

Current fabrication methods for metal interconnects and contacts are generally based on conventional photoresist fabrication procedures that require expensive equipment and multiple material/time-consuming steps. In this work, a photopatternable polyimide is synthesized via the copolymerization of a functional diamine monomer with a 1,4-dihydropyridine side-chain which can decompose under UV irradiation into a pyridine group—a promising ligand for palladium ions. After the absorption of palladium ions, the electroless copper plating is carried out to form metal patterns of copper. Copper patterns with smooth boundaries are confirmed by scanning electron microscope and atomic force microscope. Robust interfacial bonding between the copper and the polyimide film is evidenced by Scotch tape adhesion tests. The photopatternable polyimide has the advantages of low Pd consumption, easy operation without expansive equipment. The linear thermal expansion coefficient of the photopatternable polyimide remains close to the one of copper wire, demonstrating the adaptability of the photopatternable polyimide for integrated circuit application. This work presents the approach of (i) the synthesis of a novel photopatternable polyimide and (ii) its application for making flexible conductive metal structures and patterned metal interconnects, which can be expected to have tremendous potential in the field of flexible electronics.