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• PFOTES was used to enhanced the tribo-polarity and hydrophobicity of CNF-based TENG. • PFOTES-CNF-based TENG exhibit enhanced triboelectric performance. • The Isc reached 9.3 μA, which is about twice that of a pure CNF-based TENG. • The PFOTES-CNF-based TENG retains 70% of the initial output at 70% ambient humidity. Cellulose is the most abundant natural polymer on earth. Because it is renewable, biodegradable, and biocompatible, it offers distinct advantages as a starting material for bio-based triboelectric nanogenerator (bio-TENG). However, weak polarity, poor hydrophobicity, and insufficient functionalization on the natural cellulose surface severely limit the development of high-performance cellulose-based TENGs. In this work, chemical functionalization is employed to control the surface polarizability and hydrophobicity of cellulose nanofibrils (CNFs). Functional groups on the CNF surface are modified with triethoxy-1H,1H,2H,2H-tridecafluoro-n-octylsilane (PFOTES) in a straightforward and facile process. Fluorine-bearing silane chains are grafted to the surface of CNFs, which increases their triboelectric charge density and improves their hydrophobicity. Experimental results demonstrate that the surface polarity of CNFs is greatly improved after PFOTES modification. The PFOTES-CNF-based TENG exhibits good resistance to humidity and long-term cycle stability, and it retains 70% of the initial output performance at 70% ambient humidity. The short-circuit current of the PFOTES-CNF-based TENG reached 9.3 μA, which is about twice that of CNF-based TENG prior to modification. These results clearly indicate that PFOTES can be used to control CNF surface polarizability and hydrophobicity, advancing the search for durable, high-performance, degradable bio-TENGs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Developing a superhydrophobic triboelectric material. • Designing a triboelectric nanogenerator with an internal grid structure. • It can collect distributed energy and exhibit excellent output performance. The development of triboelectric nanogenerators (TENGs) has made it possible to collect large-scale distributed energy, and their applications in the field of energy harvesting are promising. However, the erosion of water molecules in humid environments is a major challenge limiting the application of triboelectric materials. In this study, superhydrophobic methylated cellulosic triboelectric materials were prepared and rectangular TENG with an internal grid structure was designed for distributed energy harvesting. Interfacial modification of the cellulose nanofibrils (CNF) surface by silica nanoparticles to form a nanoscale microstructured surface further enhances the hydrophobicity of the triboelectric material. It was found that the modified CNF triboelectric material has excellent super-hydrophobicity (WCA: 154.7°), surface roughness (RMS: 72.61), and low surface energy. In addition, the RT-TENG internal grid structure is designed to allow external impact forces to be applied more uniformly to the surface of the f triboelectric material, demonstrating excellent electrical output performance (120 V) and cycling stability (10,000 cycles) when applied to distributed energy harvesting. This study provides a novel strategy for the design and preparation of superhydrophobic triboelectric materials and guides the study of distributed energy harvesting. [ABSTRACT FROM AUTHOR]