Green Flexible Graphene–Inorganic‐Hybrid Micro‐Supercapacitors Made of Fallen Leaves Enabled by Ultrafast Laser Pulses. (5th December 2021)

• Record Type: Journal Article
• Authors: Le, Truong‐Son Dinh; Lee, Yeong A.; Nam, Han Ku; Jang, Kyu Yeon; Yang, Dongwook; Kim, Byunggi; Yim, Kanghoon; Kim, Seung‐Woo; Yoon, Hana; Kim, Young‐Jin
• Is Part Of: Advanced functional materials. Volume 32:Number 20(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-12-05
• Subjects: laser‐induced graphene -- green flexible electronics -- micro‐supercapacitors -- ultrafast lasers -- direct laser writing; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202107768
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: The development of green flexible micro‐supercapacitors (MSCs) is one of the biggest challenges in future wearable electronics. Flexible MSCs are mainly produced from non‐biodegradable synthetic polymers, resulting in massive electronic waste. Moreover, complex multi‐step fabrication increases their production cost. Here, the direct fabrication of highly conductive, intrinsically flexible, and green microelectrodes from naturally fallen leaves in ambient air using femtosecond laser pulses without any additional materials is reported. Hierarchically porous graphene is patterned on different types of leaves via a facile, mask‐less, scalable, and one‐step laser writing. Leaves consist of biominerals, which decompose into inorganic crystals that serve as nucleation sites for the growth of 3D mesoporous few‐layer graphene. The femtosecond laser‐induced graphene (FsLIG) microelectrodes formed on leaves have lower sheet resistance (23.3 Ω sq −1 ) than their synthetic polymer counterparts and exhibit an outstanding areal capacitance (34.68 mF cm −2 at 5 mV s −1 ) and capacitance retention (≈99% after 50 000 charge/discharge cycles). The FsLIG MSCs on a single leaf could easily power a light‐emitting diode or a table clock and could be applied in wearable electronics, smart houses, and Internet of Things. Abstract : Arbitrary graphene microelectrodes are directly patterned on fallen leaves in ambient air by ultraviolet ultrafast laser. The graphene microelectrodes on leaves exhibit superior electrical conductivity compared with their synthetic polymer counterparts. Due to unique hierarchical porous structures, flexible graphene micro‐supercapacitors on leaves show excellent performance that can be utilized for green wearable electronics.