Room-Temperature Self-Repairable Yet Mechanically Robust Elastomeric Triboelectric Nanogenerators Enabled by a Fast-Reversible Dual-Dynamic Network

Self-healable polymers hold great promise for durable triboelectric nanogenerators (TENGs) in sustainable energy harvesting. Incorporating dynamic bonds into polymers can enhance the self-healing, whereas mechanical properties are usually sacrificed for rapid network rearrangement. Here, we present a straightforward strategy to fabricate room-temperature self-repairable yet mechanically robust TENGs based on dual-dynamic networks of disulfide-containing poly(urethane-urea) (S-PUU) elastomers. By incorporating aromatic disulfides featuring electron-donating groups (amines) into the hard segments of polyurethane, we establish dual-dynamic networks consisting of reversible disulfide (S–S) and hydrogen bonds. The coexistence of these double dynamic bond exchanges, facilitated by the activating effect of amine groups, triggers the fast reversibility of the S-PUU networks with relaxation times as short as ∼7.8 s at room temperature. While achieving rapid self-repairability, S-PUUs simultaneously exhibit significant improvement in mechanical strength and toughness with effective energy dissipation, arising from the synergy among interchain cross-linking, rigid diphenyl inclusion, and the constant breaking–regrouping of reversible bonds. The rapid rearrangement of dual-dynamic networks enables TENGs to achieve a high self-healing efficiency of up to 96% at room temperature, without external heating or catalysts. In addition, the outstanding mechanical robustness and recoverability endow the device with a remarkably durable electricity-generating performance. Moreover, the versatile nanogenerators with favorable stretchability allow effective mechanical energy harvesting and self-powered stimulus detection in both pressing and stretching modes. This work would inspire the fabrication of TENGs combining mild-condition self-repairability and excellent mechanical performance for durable and sustainable energy harvesting.