Fallen Leaves-Based Femtosecond-Laser-Induced-Graphene for High-Performance Flexible Micro-Supercapacitors

The rapid growth of wearable and portable electronics has led to the development of microscale energy storage devices. Among these devices, microsupercapacitors (MSCs) have emerged as promising flexible energy storage devices owing to their high power density, fast charge/discharge rate, and long-term cycling stability [1-4]. Flexible MSCs were mainly made from non-biodegradable synthetic polymers, resulting a massive electronic waste. Moreover, complex manufacturing processes increase production costs. To address these challenges, we present a novel approach to fabricate green and flexible MSCs using naturally fallen leaves as a carbon precursor [5]. Our method utilize ultrashort laser pulses to create highly conductive and intrinsically flexible microelectrodes without any additional materials. The laser-induced-graphene is formed on leaves in ambient air, resulting in hierarchically porous graphene with 3D mesoporous few-layer structures. Our green flexible MSCs demonstrated excellent electrochemical performance and were confirmed to work as a power sources for various applications such as LEDs and thermometers. Furthermore, our approach offers a low-cost, renewable, and environmentally friendly alternative to traditional manufacturing processes. Overall, our green and flexible MSCs have significant potential for use in energy-storage devices for flexible/wearable electronics. References [1] M. F. El-Kady, R. B. Kaner, Nat. Commun . 4, 1475 (2013) . [2] S.-K. Hyeong, M. Park, S.-I. Kim, S. Park, K.-H. Choi, M. Im, N. Kim, T.-W. Kim, S. Lee, J.-W. Park, S. Bae, J.-H. Lee, S.-K. Lee, Adv. Mater. Technol . 7, 2101105 (2022) [3] D. Pech, M. Brunet, H. Durou, P. Huang, V. Mochalin, Y. Gogotsi, P. -L. Taberna, P. Simon, at. Nanotech . 5, 651 (2010) . [4] Y. Lee, J. Lim, Y. Cho, H. Lee, S. Park, G.-W. Lee, C.-Y. Yoo, S. Park, V. Murukeshan, S. Kim, Y.-J. Kim, H. Yoon, Chem. Eng. J. 386, 123972 (2020) [5] T. –S. Le, Y. Lee, H. Nam, K. Jang, D. Yang, B. Kim, K. Yim, S.-W. Kim, H. Yoon, Y.-J. Kim, Adv. Funct. Mater . 32, 2107768 (2022)