Lignin nanoparticles-engineered cellulose nanofibrils films with modulated surface microstructure and interfacial polarization for high-performance triboelectric nanogenerators

Cellulose nanofibrils (CNF) are promising materials for triboelectric nanogenerators (TENG) due to their biodegradability and renewability. However, their insufficient interfacial contact area and interfacial polarization capabilities restrict the enhancement of output performance. The rigid aromatic structure and abundant phenolic hydroxyl groups of lignin provide a novel approach to optimizing CNF-based TENG. In this study, maleic acid-esterified lignin nanoparticles (LNP) were introduced to synergistically regulate the surface microstructure and interfacial polarization properties of CNF films, successfully constructing high-performance lignin nanoparticles-cellulose nanofibril triboelectric nanogenerators (LCNF-TENG). LNP significantly improved the mechanical properties of LCNF films, achieving a maximum tensile strength of 163.5 MPa due to the formation of dense hydrogen-bonded networks with CNF. At an optimal LNP loading of 15 wt%, the LCNF-TENG exhibited an open-circuit voltage of 108.83 V and a charge density of 52.346 μC/m 2 , representing 461 % and 545 % improvements compared to the CNF-TENG. Atomic force microscopy and finite element simulations reveal a dual enhancement mechanism: multiscale surface roughness introduced by LNP increases the effective contact area, while dense hydrogen bonding networks promote interfacial dipole polarization. This study provides mechanistic insight into structure-function coupling and presents a scalable, environmentally friendly strategy for the design of natural polymer-based TENG, contributing to sustainable energy solutions.