Carbonized lignin-induced silk fibroin asymmetric membranes for self-powered triboelectric sensor

The advancement of wearable sensing and human-machine interaction technologies is driving the search for sustainable materials for self-powered electronics. This study deomstrates a strategy in which biomass-derived carbonized lignin (CL) is used as a functional additive to direct the hierarchical self-assembly of silk fibroin (SF). During a one-step sedimentation casting process, CL particles spontaneously accumulate under gravity, constructing a gradient asymmetric architecture that integrates a conductive bottom layer with a triboelectric top layer. Concurrently, CL acts as a nucleating agent, promoting β-sheet nucleation in SF and enhancing the mechanical strength of the composite film to 23.38 MPa. The resulting flexible triboelectric nanogenerator (TENG), paired with a PTFE counter-electrode, delivers stable electrical output across varying frequencies and pressures, sustains over 1000 working cycles, and enables real-time self-powered monitoring of joint motions. Furthermore, its monotonic pressure-dependent voltage response facilitates advanced applications such as self-powered handwriting recognition. Together with its confirmed biocompatibility in vitro, this work establishes a facile, green, and scalable manufacturing paradigm for biomass-based multifunctional TENGs, paving the way for next-generation self-powered wearable sensing systems.