In-Situ Joule Heating-Triggered Nanopores Generation In Laser-Induced Graphene Papers For Capacitive Enhancement

Laser-induced graphene (LIG) technology featuring low-cost, high-efficiency and scalability has presented great advantages in micro-supercapacitors (MSCs) fabrication. However, the limited capacitance of LIG based MSCs is still hindering their further development. Herein, we introduce joule heating as a critical in-situ treatment merged with the assembly of laser-induced graphene paper based MSCs (LIGPMSCs) toward capacitive enhancement. By increasing heating-treatment temperature from similar to 20 to 500 degrees C, the number of nanopores in LIGP continuously increases, attributed to the gradual decomposition of amorphous carbon components. The resulting joule-heated LIGP (J-LIGP) with improved specific surface area (160.97-533.49 m(2)/g) and pore volume (0.179-0.553 cm(3)/g) as well as superhydrophilic surface is highly suitable to be employed as J-LIGP-MSCs microelectrodes. By investigating process dependent performance, the J-LIGP-MSCs heated at 500 degrees C for 60 min delivers a significantly improved specific areal capacitance (CA) of 13.71 mF/cm(2) at 10 mV/s, which is approximately six-fold higher than that of unheated LIGP-MSCs. By further exploring and optimizing the process efficiency, J-LIGP-MSCs with a CA of 12.61 mF/cm(2) has been achieved by 550 degrees C heating for only 5 min. Along with superior mechanical flexibility, cyclability and structural modularity, the proposed in-situ joule heating treatment is finally proved to be a universal approach for consistently enhancing the CA of LIG based MSCs processed under various chemical modifications. (C) 2021 Elsevier Ltd. All rights reserved.