Dynamically self-adjustable liquid–liquid and self-adaptive soft-contact solid–solid triboelectric nanogenerator for wave energy harvesting

Water wave energy exhibits great potential to alleviate the global energy crisis. However, harvesting and utilizing wave energy are challenging due to its irregularity, randomness, and low frequency. Triboelectric nanogenerators (TENGs) have gained significant attention for harvesting wave energy with high efficiency. This study presents a novel ellipsoidal, pendulum-like TENG integrating both liquid–liquid (L–L) and solid–solid (S–S) triboelectricity (LS-TENG). This innovative design enables continuous wave energy harvesting and self-powered marine environment monitoring under various conditions, including temperature, humidity, and light intensity. The binary immiscible liquids within the LS-TENG’s inner soft balloon create dynamic, and self-adjustable L–L contact interfaces, significantly increasing the L–L contact area and enhancing L–L contact electrification (CE). The unique self-adaptive, soft S–S contact increases the S–S contact area compared to traditional hard point contact, better adapting to the irregular movements of waves and promoting efficient S–S CE. The LS-TENG achieves highly efficient wave energy harvesting by coupling L–L and S–S CE. Furthermore, the unique soft contact design protects the S–S interfaces from mechanical wear and damage during long-term work. The LS-TENG’s novel structure provides an innovative and effective way for water wave energy harvesting.