Sustainable lignin-based electrospun nanofibers for enhanced triboelectric nanogenerators

Recently, sustainable triboelectric nanogenerators (TENGs) based on biodegradable biomaterials have attracted tremendous attention to efficiently harvest mechanical energy in a cost-effective and environmentally friendly strategy. Lignin, as the second most abundant biopolymer on earth, however, requires further development for TENGs with improved power generation. Herein, we have fabricated sustainable hybrid lignin-based nanofibers (LNFs) via electrospinning and prepared LNF-based TENGs. By adjusting the lignin content in the composite nanofibers, we achieved the tuning of LNFs' microstructure and tribo-polarity. The obtained TENGs are endowed with enhanced output performance due to the strong tribo-positivity of lignin and the high specific surface area of the 3D-network LNFs. The optimized output is realized after the trade-off between improved tribo-positivity and formed beads that impact the surface area in LNFs when increasing lignin concentration. Moreover, the correlation between the electrical performance of LNF-TENGs and the external pressing force/frequency is explored. We also demonstrate the practical applications of LNF-TENGs in efficient energy harvesting and self-powered pressure sensing. Our work shows the feasibility of using LNFs to prepare sustainable TENGs with enhanced performance and provides novel insights into the high-value utilization of the low-cost industrial waste lignin.