One-step, laser-induced self-generation of nanoporous hybrid electrodes enables facile fabrication of high-performance and flexible micro-supercapacitors.

Laser direct processing is a promising approach for future flexible electronics because it enables easy, rapid, scalable, and lowtemperature fabrication without using expensive equipment and toxic material. However, its application for nanomaterials with high chemical susceptibility, such as representatively Cu, is limited because severe oxidation occurs under ambient conditions. Here, we report the methodology of a transversally extended laser plasmonic welding process, which outstandingly improves the electrical performance of a Cu conductor (4.6 μΩ·cm) by involving the spatially concurrent laser absorption to the surface oxide-free Cu nanoparticles (NPs). Physical/chemical properties of fabricated Cu conductors are fully analyzed in perspectives of the mechanism based on the thermo-physical-chemical interactions between photon energy and pure Cu NPs. The resultant Cu conductors showed an excellent durability in terms of bending and adhesion. Furthermore, we successfully demonstrated a single layer Cu-mesh-based touch screen panel (TSP) on thermally sensitive polymer film as a breakthrough of typical metal oxide-based transparent touch sensors. The Cu metal mesh exhibited high transmittance (95%) and low sheet resistance (30 Ω/square). This self-capacitance type and multitouchable TSP operated with a fast response, high sensitivity, and durability.

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Herein, a novel stretchable Cu conductor with excellent conductivity and stretchability is reported via the flash‐induced multiscale tuning of Cu and an elastomer interface. Microscale randomly wrinkled Cu (amplitude of ≈5 µm and wavelength of ≈45 µm) is formed on a polymer substrate through a single pulse of a millisecond flash light, enabling the elongation of Cu to exceed 20% regardless of the stretching direction. The nanoscale interlocked interface between the Cu nanoparticles (NPs) and the elastomer increases the adhesion force of Cu, which contributes to a significant improvement of the Cu stability and stretchability under harsh yielding stress. Simultaneously, the flash‐induced photoreduction of CuO NPs and subsequent Cu NP welding lead to outstanding conductivity (≈37 kS cm−1) of the buckled elastic electrode. The 3D structure of randomly wrinkled Cu is modeled by finite element analysis simulations to show that the flash‐activated stretchable Cu conductors can endure strain over 20% in all directions. Finally, the wrinkled Cu is utilized for wireless near‐field communication on the skin of human wrist.

Ultrafine copper nanopalm tree‐like frameworks conformally decorated with iron oxide (Cu NPF@Fe2O3) are prepared by a facile electrodeposition method utilizing bromine ions as unique anisotropic growth catalysts. The formation mechanism and control over Cu growth are comprehensively investigated under various conditions to provide a guideline for fabricating a Cu nanoarchitecture via electrochemical methods. The optimized Cu NPFs exhibit ultrathin (<90 nm) and elongated (2–50 µm) branches with well‐interconnected and entangled features, which result in highly desirable attributes such as a large specific surface area (≈6.97 m2 g−1), free transfer pathway for Li+, and high electrical conductivity. The structural advantages of Cu NPF@Fe2O3 enhance the electrochemical kinetics, providing large reactivity, fast Li+/electron transfer, and structural stability during cycling, that lead to superior electrochemical Li storage performance. The resulting Cu NPF@Fe2O3 demonstrates a high specific capacity (919.5 mAh g–1 at 0.1 C), long‐term stability (801.1 mAh g–1 at 2 C, ≈120% retention after 500 cycles), and outstanding rate capability (630 mAh g–1 at 10 C).