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Herein, a stacked Ge/Cu nanowire (NW) laminate made by stacking several Ge/Cu nanowire laminates accompanied by the conductive glue adhesives is used to achieve high capacity output per unit area (>10 mA h cm–2). The combination of Cu NWs and conductive adhesives constructs a tough and conducting network through the electrode, and the stacked Ge/Cu nanowire laminate electrodes can load an ultrahigh mass of 14.8 mg Ge per unit area and provide an areal capacity output over 16 mA h cm–2. A full-cell with an areal capacity of 11 mA h cm–2 built by stacked Ge/Cu nanowire laminate anode and Li(Ni0.5Co0.3Mn0.2)O2 cathode was prepared and used to supply electricity for electronic devices, demonstrating their potential to be a candidate anode for high areal capacity Li-ion microbatteries that can be used for high-tech and integrated microsystems with limited space.

Cu Foil, a thin sheet of Cu, is the common anode current collector in commercial lithium ion batteries (LIBs) which accounts for ∼ 10 wt% of the total cell weight. However, thickness reduction of LIB-based Cu foils below 6 μm has been limited by the incapability of conventional rolling annealing or electrodeposition process. We here report a new type of Cu foil, so called Cu nanowire foil (CuNW foil), for use as an LIB anode current collector. We fabricate Cu NW foils by rolling press Cu nanowire fabric to reduce the thickness down to ∼1.5 μm with an areal weight down to ∼1.2 mg cm−2 and a density approximately 96% to that of bulk Cu. The rough surface and porous structure of CuNW foil enable better wetting and adhering properties of graphite slurry on foil. In full cell examination, a cell of a areal capacity of 3 mAh cm−2 exhibits 83.6% capacity retention for 600 cycles at 0.6 C that meets the standard specification of most commercial LIBs. As a proof-of-concept of demonstration, we fabricate a 700 mA pouch-type battery implemented with graphite-Cu NWs foil anodes to serve as energy supply to operate electronic devices.

Metal nanowires are promising for their applications including electrical connectors, transparent conductive electrodes and conductive additives, but the use of metal nanowires as photothermal agents to convert light to heat has yet to be reported. Here we synthesized dispersible polyethylene glycol-coated (PEGylated) copper nanowires (CuNWs) and showed for the first time that PEGylated CuNWs were able to convert near-infrared (NIR, 808 nm) light into heat at a photothermal efficiency of 12.5%. The PEGylated CuNWs exhibited good reusability and enabled rapid temperature rise to50 °C in 6 min by NIR irradiation. The PEGylated CuNWs were flexible and intertwined around the cancer cells, which, upon NIR irradiation, allowed for direct heat transmission to cells and effectively triggered cancer cell ablation in vitro. Intratumoral injection of PEGylated CuNWs into colon tumor-bearing mice and ensuing NIR irradiation for 6 min significantly raised the local temperature to50 °C, induced necrosis, and suppressed tumor growth. Compared with other NIR light absorbing noble metal-based nanomaterials, PEGylated CuNWs are relatively easy to synthesize in both laboratory and large scales using the low cost copper. This study demonstrated the potential of PEGylated CuNWs as a new cost-effective photothermal agent, and paved a new avenue to using CuNWs for cancer therapy.

Metallic nanostructures possessing higher surface-to-volume ratio provide a more accessible surface to catalyze chemical reactions compared to the bulk materials. However, scaling up the nanostructures remains complicated and limits the applications as industrial catalysis. Here, we demonstrate a facile method to fabricate a robust and versatile Cu nanostructure at a centimeter scale as an efficient photothermal catalytic reactor. By drop-casting the solution of Cu nanowires into a Teflon mold after solvent evaporation followed by annealing in the H2/Ar atmosphere, a Cu nanowire fabric possessing a network structure with a high density of porosity is formed. The Cu fabric exhibits a strong absorptance at the spectral range of 400–1200 nm owing to the interband transition, the surface plasmon resonances of Cu nanowires with their near-field coupling, and “light trapped effect” in the network structures. Exposure to 808 nm laser allows for the elevation of the temperature across the whole structure within 2 s and maintaining a stable temperature up to 250 °C for 2 h. A heterogeneous copper-catalyzed azide-alkyne cycloaddition reaction is performed using Cu nanowire fabric illuminated by an 808 nm laser. A repeatable yield of >90% with a reaction time of 4 h, an order of magnitude shorter than conventional copper catalysts at ambient temperature, is achieved suggesting the Cu nanowire fabric as a robust photothermal catalytic reactor.

Large-area conducting transparent conducting electrodes (TCEs) were prepared by a fast, scalable, and low-cost spray deposition of copper nanowire (CuNW) dispersions. Thin, long, and pure copper nanowires were obtained via the seed-mediated growth in an organic solvent-based synthesis. The mean length and diameter of nanowires are, respectively, 37.7 μm and 46 nm, corresponding to a high-mean-aspect ratio of 790. These wires were spray-deposited onto a glass substrate to form a nanowire conducting network which function as a TCE. CuNW TCEs exhibit high-transparency and high-conductivity since their relatively long lengths are advantageous in lowering in the sheet resistance. For example, a 2 × 2 cm(2) transparent nanowire electrode exhibits transmittance of T = 90% with a sheet resistance as low as 52.7 Ω sq(-1). Large-area sizes (50 cm(2)) of CuNW TCEs were also prepared by the spray coating method and assembled as resistive touch screens that can be integrated with a variety of devices, including LED lighting array, a computer, electric motors, and audio electronic devices, showing the capability to make diverse sizes and functionalities of CuNW TCEs by the reported method.