Natural wood-based triboelectric nanogenerators with high fire-safety for energy harvesting toward intelligent buildings

Developing advanced fire-safe and self-energy-supplied wood materials is of significant importance for environmental science, wearable electronics, and human–machine communication, as witnessed in the concept of smart living. However, knowing how to simultaneously achieve high flame retardancy and strong triboelectric effects remains critical for such sustainable materials. Here, we demonstrate a wood-based triboelectric nanogenerator with simultaneous high fire-safety and triboelectric energy generation performances. The incorporation of a polar polycationic polymer offers significantly enhanced triboelectric effects to natural woods, generating an output power density of 119.7 mW m−2. The P–N synergistic flame retardancy enables the high fire-safety of the nanogenerators in terms of a condensed and vapor phase flame retardant mechanism. Notably, the nanogenerators exhibit self-extinguishing behavior, and over 32% and 73% of the electrical output is still retained even after continual exposure to a flame for 50 s or in the case of the damaged area covering 60% of the nanogenerator, respectively. We further demonstrate applications of the nanogenerators for self-powered wireless fire alarm , emergency rescue guidance, and real-time motion monitoring. Utilizing the structural design involving polar N-containing polycationic polymers to enhance triboelectric performance and confer fire resistance offers an effective approach for developing advanced wood materials geared towards intelligent buildings.