Humidity-Adaptive Triboelectric Contact/Noncontact Sensing and Energy Harvesting Enabled by Plant-Ash- and Ammonium-Salt-Coengineered Cellulose Aerogel

Internet of Things advancement requires sustainable, environmentally adaptive self-powered sensing. Triboelectric nanogenerators (TENGs) are promising self-powered sensors but exhibit poor environmental compatibility, humidity stability, and contact/noncontact sensing efficiency. Herein, a composite aerogel was fabricated using ammonium-salt-modified cellulose fibers and microfibrillated cellulose to form a multiscale entangled network skeleton, incorporating plant-leaf-derived ash (PLSH) as a functional dopant via low-temperature freezing (–5 °C) and ambient drying. The aerogel exhibits excellent mechanical properties, recyclability, and biodegradability. Synergistic PLSH and ammonium salt modification enhances charge density through ion/interface polarization, enabling an aerogel-based TENG to deliver outstanding electrical output performance: an open-circuit voltage of 442.9 V, a maximum power density of 154.5 μW/cm2, high pressure sensitivity (20.65 V/N, 1–10N), remarkable humidity adaptability, and fatigue resistance (stability over 14,000 cycles at 83% RH). The output performance was effectively tuned by adjusting ammonium salt concentration, PLSH content, and MFC dosage. The process accommodates diverse PLSH sources. The TENG powers 632 LEDs and enables wireless contact/noncontact modes for human-activity monitoring. This work provides a scalable route to eco-compatible, humidity-adaptive cellulose TENGs for energy harvesting and intelligent multifunctional sensing.