Polypyrrole@CNT@PU Conductive Sponge-Based Triboelectric Nanogenerators for Human Motion Monitoring and Self-Powered Ammonia Sensing

Abstract

Elastic sponges are ideal materials for triboelectric nanogenerators (TENGs) to harvest irregular and random mechanical energy from the environment. However, the conductive design of the elastic materials in TENGs often limits its applications. In this work, we have demonstrated that an elastic conductive sponge can be used as the triboelectric layer and electrode for TENGs. Such an elastic conductive sponge is prepared by a simple way of adsorbing multiwalled carbon nanotubes and monomers of pyrrole to grow conductive polypyrroles on the surface of an elastic polyurethane (PU) sponge. Due to the porous structure of the PU sponge and the conductive multiwalled carbon nanotubes (MWCNTs), PPy on the surface of PU could provide a large contact area to improve the output performance of TENGs, and the conductive sponge-based TENG could generate an output of open-circuit voltage of 110 V or a short-circuit current of 12 μA, respectively. The good flexibility of the conductive PU sponge makes the TENG harvest the kinetic energy of disordered motion with different amplitudes, allowing for human motion monitoring. Furthermore, the porous structure of PU and the synergistic effects of PPy and MWCNTs enable the conductive sponge to sense NH 3 as a self-powered NH 3 sensor. This work offers a simple way to construct a flexible TENG system for random mechanical energy harvesting, human motion monitoring, and self-powered NH 3 sensing.

Review of Carbon Nanotube Research and Development: Materials and Emerging Applications

“…In addition, CNTs have a large specific surface area, increasing their susceptibility to external changes. A variety of sensors using CNTs have been assembled, such as a pressure sensor using conductive polymers, CNTs, and poly(dimethylsiloxane) (PDMS) (CN2023116972905A), CNTs supported on polyurethane for use as a triboelectric generator, movement sensor, or chemosensor, with superhydrophobic surface as a flexible airflow sensor, in concert with nickel triphenylene complexes as a nonbiological glucose sensor, and as nanoresistors to detect disinfectants . MWCNTs have been used in combination with samarium to detect solvent vapors, with polyaniline (PANI) to form ammonia-responsive materials, with epoxy resin to form a strain-sensing conductive material, and with polyurethane and polypyrrole to form a bendable pressure sensor (in the latter sensor, the use of components with differing compressibilities was critical to its effectiveness).…”