Femtosecond Laser Ultrafast Atomic Scale Renovating Laser‐Induced Graphene

Abstract Renovation technology for laser‐induced graphene (LIG) is critical for customizing and expanding its applications. However, existing renovation technology for LIG has been rarely reported and are constrained by the limitations such as poor precision, variable heal parameters, and lack of multifunctionality. Herein, the first time a simple and efficient femtosecond laser method is introduced for atomic scale renovation LIG (FLR‐LIG). The ultrafast and efficient thermal conversion of femtosecond laser pulses by LIG triggers the rearrangement of carbon atoms to heal defects. Raman spectroscopy, atomic‐resolution images, and density functional theory calculations demonstrate that femtosecond laser treatment successfully enhances structural ordering and reduces defect density, thereby lowering resistance fivefold, from 593 Ω to as low as 118 Ω. Furthermore, this femtosecond laser renovation method offers advantages in patterned and high‐precision processing, while also transforming LIG from superhydrophobic to superhydrophilic, enabling its use in high‐performance water evaporation. The FLR‐LIG achieves a high water evaporation rate of 7.91 kg m −2 h −1 at 4 V. Additionally, it is shown that the FLR‐LIG is useful for the purification of organic dyes, acidic/alkaline wastewater, and seawater desalination.