Cellulose-based triboelectric nanogenerator for self-powered NH3 sensing and intelligent freshness monitoring of meat

During meat spoilage, microorganisms rapidly proliferate and decompose nitrogen-containing compounds such as proteins, releasing volatile alkaline substances, including ammonia (NH 3 ). Among these, NH 3 is widely recognized as a key indicator gas for evaluating changes in food freshness. To enable real-time monitoring of perishable food quality, this study developed an integrated self-powered smart material system based on cellulose nanofibers (CNF) with combined sensing and power-generation functions. Ti 3 C 2 T x was used as the NH 3 -sensitive functional filler, and a Ti 3 C 2 T x /SnO 2 heterojunction was formed by introducing SnO 2 , enabling synergistic enhancement of both NH 3 sensing sensitivity and triboelectric output performance. In addition, a TEOS-induced cross-linked network was introduced to enhance the structural stability and electrical performance of the composite film. The results show that the device achieves a triboelectric open-circuit voltage (Voc) of 82 V and a maximum instantaneous power density of 7.99 μW·cm −2 . It exhibits a stable linear response over the NH 3 concentration range of 5–120 ppm, with response and recovery times of 14 s and 32 s, respectively, and maintains good long-term stability over 20 days. Within the ppm-level concentration range relevant to meat spoilage, the sensor maintains continuous and distinguishable response signals under varying humidity conditions, enabling trend identification and dynamic monitoring of freshness changes. Furthermore, pork storage experiments demonstrated that the system could continuously track NH 3 release and effectively distinguish freshness changes under storage conditions of 20 °C, 4 °C, and − 20 °C, highlighting its significant potential for self-powered intelligent food packaging applications.