Cellulose Functional Materials for Fiber-Based Energy Harvesting and Storage Devices

Developing sustainable options for energy conversion and storage in textiles is needed to power future wearable “Internet of Things” (IoT) electronics. This process must consider new possible alternatives that address questions of sustainability, reuse, repair, or even a second life application. Herein, we pair stretch-broken carbon fiber yarns (SBCFYs), as current collectors, and an in-situ regenerated cellulose-based ionic hydrogel (RCIHs) as an electrolyte, to fabricate 1D fiber-shaped supercapacitors (FSCs). The areal specific capacitance reaches 433.02 µF cm ^-2 at 5 µA cm ^-2 , while the specific energy density is 1.73×10 ^-2 µWh cm ^-2 . The maximum achieved specific power density is 5.33×10 ^-1 mW cm ^-2 , at 1 mA cm ^-2 . The 1D FSCs possess a long-life cycle, 92 % capacitance retention after 10000 consecutive cyclic voltammetry cycles, higher than similar ones using reference PVA/H₃PO₄ gel electrolyte.<br/>We also propose Triboelectric Generator Yarns (TEG yarns) using a new method for depositing PDMS directly onto conductive carbon yarns. The in-situ PDMS curing method described in this study allows the fast formation of a uniform thick coating over conductive surfaces regardless of their roughness. Single-electrode configuration TEG yarns are developed, and their electrical output is optimized by precisely adjusting the PDMS layer thickness and by changing the chemical and physical nature of the SBCFYs surface, reaching a power density of 74.1 μW cm^-2. We demonstrate that asymmetric electrophoretic deposition of nanocrystalline cellulose films results in increase of 100% of the TEGs electrical output to around 142.7 μW cm^-2.