Self-healing hydrogel electrode for a triboelectric nanogenerator toward self-powered bridge monitoring

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Bridge health monitoring requires flexible self-powered sensors capable of detecting mechanical disturbances under low-maintenance conditions. However, soft electrodes for triboelectric sensing still face challenges in simultaneously achieving mechanical robustness, continuous charge transport, self-healing capability, and environmental adaptability. Here, a dual-dynamic-network conductive soft electrode composed of poly(vinyl alcohol) (PVA), tannic acid (TA), carboxymethyl chitosan (CMCS), borax, MXene, and silver nanowires (AgNWs) was developed for a contact–separation triboelectric nanogenerator (PTCBMA-TENG). Dynamic borate ester bonds and hydrogen bonds enabled reversible network reconstruction, while the MXene/AgNWs sheet-wire framework provided continuous conductive pathways and a finer interconnected porous structure. The optimized PT 1 C 8 BM 6 A 6 electrode exhibited a tensile stress of 0.14 MPa, an elongation at break of 636%, and a compressive stress of 1.18 MPa at 86% strain, while recovering electrical continuity after 5 min of room-temperature self-healing. The 30 × 30 mm 2 PTCBMA-TENG delivered an open-circuit voltage of 581 V, a short-circuit current density of 1.133 mA m −2 , and a transferred charge density of 37.24 μC m −2 at 5 Hz, 4 mm, and 40 N, with a maximum instantaneous power density of 0.32 W m −2 at 10 MΩ. The device generated distinguishable signals under simulated vehicle passage, bearing settlement, expansion-joint displacement, and vessel-bridge collision, and maintained stable waveforms over approximately 20,000 contact-separation cycles. These results demonstrate the potential of the PTCBMA-TENG as a flexible self-powered sensing unit for bridge condition monitoring, while further multi-source interference analysis, environmental durability evaluation, and full-scale field validation remain necessary.