Surface and Interface Modified Cellulose Nanofibers for Direct Writing and Printing Triboelectric Nanogenerator

In recent years, cellulose has garnered significant attention in the preparation of triboelectric nanogenerators due to its excellent biodegradability and reproducibility. However, the weak surface polarity and insufficient surface functional groups have considerably constrained its progress towards achieving high-performance TENG. Here, nanocellulose (CNFs) was employed as the friction layer material for the triboelectric nanogenerator. The surface interface was modified through chemical treatment, introducing two functional groups, -NH2 and -F. Besides analyzing the electron gain and loss capabilities and polarity of two distinct functional celluloses, functionalized CNFs were also employed in a direct-writing approach to fabricate three-dimensional structures for TENG applications. Furthermore, CNFs with enhanced surface and interface can also enhance the electrical output performance of triboelectric nanogenerators. The results indicated that when the mass ratio of epoxy propyl trialkylamine chloride (EPTMAC) to cellulose was 2.0, the cationic degree was at its highest. The introduction of -F, achieved by using nano SiO2 and PFOTS, not only rendered the water contact angle of FCNF-SiO2 aerogel superhydrophobic at 150° but also yielded the maximum output voltage when the mass ratio of dried fiber to nano SiO2 was 3.0. These results further demonstrate the irreplaceable advantages and practical application potential of CNFs in the environmentally friendly mechanical energy collection system, specifically in triboelectric nanogenerators.