Tribo-mechano transduction of solid-liquid triboelectric nanogenerators via boundary layer theory

Solid-liquid triboelectric nanogenerators currently suffer from an incomplete theoretical framework, which limits the accurate prediction of their energy conversion mechanisms and electrical performance. To address this challenge, this work proposes a novel solid-liquid electromechanical coupling model, inspired by the solid-solid sliding mode and boundary layer theory. A key innovation lies in replacing solid materials in the traditional solid-solid sliding model with liquid boundary layers, enabling the first theoretical investigation of electromechanical characteristics of the solid-liquid triboelectric nanogenerators at the boundary layer scale. The model is verified via a U-anti-rolling tank based simulation platform, and the solid-liquid electrical performance formula is derived through curve fitting of experimental data from a custom-built tribo-experimental setup. Theoretical analysis reveals that the conversion rate from water's dissipated kinetic energy to electrical energy reaches 11.41 %, while experimental validation under low-frequency excitations confirms the model's generalization and effectiveness. Further exploration of the mapping relationship between electrical performance and anti-rolling behavior during the roll motion of the tank shows that electrical output first increases and then decreases with rising rolling angles, and gradually declines with higher initial water levels in the tank. This model fills the gap in the theoretical system of solid-liquid triboelectric nanogenerators, offers a reliable tool for performance prediction, and provides valuable insights for optimizing the coupling between dissipated kinetic energy utilization and electrical energy replenishment in anti-rolling sensing applications.