High-performance supercapacitor and ultra-sensitive humidity sensor based on bifunctional NiCo2O4/g-C3N4 nanocomposites powered by triboelectric nanogenerator.

• Bifunctional material NiCo 2 O 4 /g-C 3 N 4 was prepared. • It is used for both supercapacitors and humidity sensors. • The developed system can be used for non-contact human–machine interaction. • The system powered by triboelectric nanogenerator can be self-started. Flexible wearable humidity sensor (HS) has become indispensable in various fields such as man–machine interaction, biomedical applications, and industrial environmental monitoring. In particular, the HS powered by supercapacitor (SC) can meet the demand of environmental protection. In this study, an integrated SC and HS system (SCHS) based on the bifunctional material NiCo 2 O 4 /g-C 3 N 4 is proposed. Additionally, a humidity signal detection and wireless transmission device is developed to match SCHS. The large surface area of g-C 3 N 4 provides a significant number of surface-active sites that facilitate its synergistic effect with NiCo 2 O 4 , which has high electrochemical activity and excellent conductivity. Their synergistic effect makes g-C 3 N 4 /NiCo 2 O 4 nanocomposites not only show remarkable sensitivity (1471 kΩ/% RH@11 % RH) to humidity sensing, but also show ultra-high specific capacitance (1061F g−1@0.5 A g−1 current density) on supercapacitors. The SCHS with excellent performances is used for non-contact human–computer interaction, respiratory monitoring of patients with respiratory diseases and humidity monitoring in hazardous industrial environments. In addition, a freestanding-rotation-disk (FRD-TENG) is used as a backup power supply for humidity monitoring system and wireless transmitter module in emergency situations. This work provides a universal and effective strategy for reducing the spread of infectious diseases and protecting lives and property. [ABSTRACT FROM AUTHOR]