Direct fabrication of high performance moisture-driven power generators using laser induced graphitization of sodium chloride-impregnated cellulose nanofiber films. (February 2022)

• Record Type: Journal Article
• Authors: Eun, Jakyung; Jeon, Sangmin
• Is Part Of: Nano energy. Volume 92(2022)
• Publication Date: 2022-02
• Subjects: NaCl-impregnated cellulose nanofiber -- Laser induced graphitization -- Moisture-driven power generator; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2021.106772
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: High performance moisture-driven power generators were developed by laser induced graphitization (LIG) of sodium chloride-impregnated cellulose nanofiber films (CNFs). CNFs impregnated with different amounts of NaCl were obtained by immersing CNFs in NaCl solutions of various concentrations. A CO2 laser engraver was employed to convert the CNFs to porous graphitic carbon films (GCFs) under ambient conditions. By focusing the laser beam on the top surface of the CNF, the laser intensity was the highest on the top surface and gradually decreased toward the bottom surface. Since the focal temperature of the laser beam was higher than the boiling point of NaCl, the NaCl particles near the top surface evaporated more rapidly, creating a NaCl concentration gradient along the thickness direction. When the GCF was exposed to moisture, the dissociated ions migrated between the top and bottom surfaces, producing an electrical current. The maximum voltage and current outputs were 0.65 V and 550 μA/cm 2, respectively, at 90% relative humidity (RH). Due to abundant dissociated ions, the current output was produced continuously rather than pulsed, and was the highest current reported so far. We demonstrated that six vertically stacked GCFs (each 3 mm × 3 mm × 240 µm in size) at 75% RH were sufficient to turn on green light emitting diodes (LEDs) operating at an onset potential of 2 V for 48 h without any auxiliary devices, such as rectifier circuits and capacitors. Graphical Abstract: ga1 Highlights: Laser induced graphitization was used to create a NaCl concentration gradient along the thickness direction of GCF21. The voltage and current outputs of the GCF21s were 0.65 V and 550 µA/cm 2, respectively, at 90% RH. The current output was produced continuously rather than pulsed, and was the highest current reported so far. The six vertically stacked GCFs were sufficient to turn on four LEDs for 48 h without a separate rectifier circuit and capacitor.