Laser-Induced Graphene Supercapacitors by Direct Laser Writing of Cork Natural Substrates

Abstract

Interdigitated and square laser-induced graphene (LIG) electrodes were successfully fabricated by direct laser writing of common natural cork bottle stoppers. The laser graphitization process was performed with a low-cost hobbyist visible laser in a simple, fast, and one-step process under ambient conditions. The formation of LIG material was revealed by extensive characterization using Raman, attenuated total reflection-Fourier transform infrared (ATR-FTIR), and X-ray photoelectron (XPS) spectroscopies. Electron microscopy investigation showed that the formed LIG structure maintained the hierarchical alveolar structure of the pristine cork but displayed increased surface area, disorder, and electrical conductivity, promising for electrochemical applications. Open planar and sandwich supercapacitors, assembled from fabricated electrodes using poly(vinyl alcohol) PVA/H + as an electrolyte, exhibited a maximum areal capacitance of 1.56 mF/cm 2 and 3.77 mF/cm 2 at a current density 0.1 mA/cm 2 , respectively. Upon treatment with boric acid (H 3 BO 3 ), the areal capacitance of the resulting boron-doped LIG devices increased by ca. three times, reaching 4.67 mF/cm 2 and 11.24 mF/cm 2 at 0.1 mA/cm 2 current density for planar and sandwich configurations, respectively. Supercapacitor devices showed excellent stability over time with only a 14% loss after >10 000 charge/discharge cycles. The easy, fast, scalable, and energy-efficient method of fabrication illustrated in this work, combined with the use of natural and abundant materials, opens avenues for future large-scale production of "green" supercapacitor devices.

Infrared Laser‐Induced Graphene Sensor for Tyrosine Detection

“…The signal at 2700 cm −1 refers to 2D band, originating from second order zone‐boundary phonons [22] . The ratio I D /I G ≈1 shows the crystalline nature of the surface indicating the formation of highly ordered graphite and nanocrystalline graphitic domains characteristic of randomly stacked graphene sheets [31] . Additionally, the 2D band peak was fitted by a single, sharp Lorentzian with full width at half‐maximum intensity (FWHM) of 56 cm −1 , and confirms the profile of randomly stacked graphene layers along the c axis, normally found in infrared laser writing of polyimide sheets [22,23,32] .…”

Biocompatible Parylene-C Laser-Induced Graphene Electrodes for Microsupercapacitor Applications

“…In addition, as previously shown in Figure B, the produced LIG layer is very thin (less than 50 μm). Therefore, the obtained specific capacitance should in principle be lower than the values obtained for thicker and porous substrates such as paper , and other cellulose-based materials, ,− for instance. Moreover, higher capacitances have also been obtained for doped graphene/LIG electrodes , or systems prepared by more complicated or expensive methods. , Nevertheless, the specific capacitance achieved represents a good result considering the lower LIG thickness and undoped nature.…”

An Integrated Cathode Engineered by Hierarchical Honeycomb‐Like Copper‐Molybdenum Sulfide Nanosheets for Hybrid Supercapacitor with Improved Energy Storage Capability

“…[65] Moreover, the relaxation time (τ 0 = 1/f 0 ) is employed to assess the charging kinetics during redox reactions, which is typically calculated by the characteristic frequency (f 0 ) at the phase angle of 45°. [66] The τ 0 value for the CuÀ MoÀ S NSs-Before is found to be 1.8 s, suggesting the fast charge transfer and highly efficient ion diffusion. [67,68] For practical application, the cyclic stability of electrode materials also needs to be considered.…”