Fractal dendrites are extensively observed in industry, especially in the electrochemical deposition process. The fractal dendrite electrodeposition behavior of quasi-two-dimensional Cu (Q2D-Cu) metal based on the wire is examined via direct electrodeposition using a thin layer reactor. Here, to explain the fractal growth mechanism, the directional migration and random walking of ions are introduced in the traditional diffusion-limited aggregation model, and fractal patterns consistent with the experimental results are successfully simulated. In addition, the Cu fractal dendrite structure is finely adjusted by varying electrodeposition conditions, demonstrating its great potential for further optimization. The CuO/Q2D-Cu fractal dendrite photothermal device fabricated through in situ assembly of CuO nanowires on Cu fractal dendrite has good photothermal conversion ability. Therefore, metal fractal dendrites, which are considered harmful in the electroplating industry, have application prospects in the photothermal field.

Advanced personal thermal management fabrics are being developed to realize improved human body thermal comfort and effectively regulate heat exchange between the human body and surroundings. Fiber‐based thermal management fabrics were directly worn on soft and curved multiple curvature human body. Here, we designed a flexible photothermal fiber based on copper fractal dendrites with abundant CuO nanowires. Well‐aligned Cu fractal dendrite fiber was electrodeposited template‐freely via a low‐cost and scalable process in an aqueous solution. Then, flexible CuO@Cu fractal dendritic photothermal fiber was fabricated by direct in‐situ oxidation and calcination of Cu fractal dendrites. Furthermore, the CuO@Cu fractal dendritic photothermal fiber can be woven into photothermal fabric by the traditional jacquard embroidery process. The temperature of photothermal fabric can be adjusted within the range of 35‐65 °C by adjusting the number of photothermal fibers, which can be achieved with comfortable wearing of human thermal management and hot compress of hyperthermia to relieve local pain. Therefore, the Cu fractal dendrites have shown considerable potential for promoting the photothermal conversion of flexible personal thermal management.This article is protected by copyright. All rights reserved.