Ultralight, Flexible, and Hydrophobic Monolithic Sponge-Structured Triboelectric Nanogenerator for Taekwondo Applications

Accurate and real-time strike monitoring is essential for fair officiating, training optimization, and enhancing the viewing experience in competitive sports. Here, this study develops a single-electrode liquid-metal-embedded sponge triboelectric nanogenerator (LPS-TENG) fabricated by incorporating a gallium–indium alloy (GaIn) into a polydimethylsiloxane sponge matrix. The device demonstrates reversible compressibility, tunable mechanical compliance, excellent hydrophobicity (water contact angle 129°), rapid response (50 ms), high durability (stable output after 7500 compression cycles), and long-term stability (4.7% output decay after 60 days). These merits were leveraged to integrate the LPS-TENG into taekwondo chest protectors and helmets, achieving detection of strike positions and analysis of complex kicking techniques during daily training. Furthermore, a self-powered wireless strike analysis system was developed, enabling automated strike localization and score recording for real-time referee assistance. This work highlights the potential of TENG-based self-powered sensing systems in intelligent sports equipment and provides a paradigm for the integration of energy harvesting, performance analytics, and fair officiating in combat sports.