Robust UV-curable triboelectric supramolecular eutectogels for self-powered soft electronics enabled by lignin-based photoinitiators

Eutectogels hold considerable promise soft electrodes for high-performance flexible triboelectric nanogenerator (TENG) due to their tunable mechanical properties and environmental stability. However, conventional eutectogels with single linear polymer chains often exhibit poor mechanical strength as well as undesirable migration of components (e.g., initiators), which compromise device stability and limit their environmental adaptability in high-performance energy harvesting. Here, lignin was molecularly engineered into branched lignin nanospheres (BLNS) functionalized with polymerizable acrylate groups. In a deep eutectic solvent system, BLNS simultaneously enabled rapid self-initiated UV polymerization (97.3% C C conversion) and constructed a robust, non-migrating crosslinked network, yielding triboelectric supramolecular eutectogels (SEG). Specifically, benefiting from branched backbone and nanoreinforcing effect of the BLNS, the resulting SEG achieved exceptional mechanical robustness (tensile strength of 1.76 MPa, toughness of 5.10 MJ/m 3 ) and strong adhesion (1.21 MPa). The SEG-based sensor exhibited a high ionic conductivity of 4.50 mS m −1 and a gauge factor of 3.3, while maintaining stable sensing performance over a wide temperature range (−30 to 80 °C) and under varying humidity conditions (30–90% RH), demonstrating excellent adaptability to harsh environmental conditions. As a proof-of-concept, a TENG was constructed using the SEG as the flexible electrode, with open-circuit voltage remaining stable over 6000 contact–separation cycles, underscoring the robustness and operational stability essential for reliable self-powered soft electronic systems. This work establishes a versatile strategy for designing multifunctional lignin-based materials for next-generation self-powered electronics.