Biomimetic Microfractals Based Flexible Triboelectric Nanogenerators

ABSTRACT Flexible TENGs are promising for self‐powered wearables, but combining high output, mechanical compliance, and low material use remains challenging. Here, we report a biomimetic microfractal TENG (BM‐TENG) inspired by leaf‐skeleton vascular architectures, where the hierarchical network serves as both porous current‐collector scaffold and template for triboelectric surface replication. Copper nanowires immobilized along the microfractal pathways form guided and locally bundled conductive networks, enabling a low sheet resistance of ∼15 Ω sq − 1 and >1000 fold reduction in sheet resistance compared with a planar control. Replication of the same architecture into electrospun Nylon‐6 and PVDF layers creates a compliant multiscale topography that enhances charge generation. The BM‐TENG delivers ∼52 V open‐circuit voltage, ∼3.2 µA short‐circuit current, and ∼67.24 nC transferred charge per cycle while using 50% lower CuNW loading, compared with ∼26 V, ∼1.23 µA, and ∼27.35 nC for the planar control. Using projected device area as the primary normalization basis, BM‐TENG achieves a current density of ∼3 mA m − 2 and power density of ∼136.91 mW m − 2 , compared with ∼1.13 mA m − 2 and 135.80 mW m − 2 for the planar control. As secondary metrics, effective‐material‐area normalization gives ∼10 mA m − 2 and ∼456.35 mW m − 2 for the BM‐TENG. The device also maintains stable output over ∼10000 cycles.