Characterizing graphite-based pencil material for mechanical energy harvesting and sensing application

Several techniques had been employed to improve the electrical power of triboelectric nanogenerator since the invention of the device. These techniques include physical structure modification and insertion of nanoparticles in polymer matrix. Herein, we are introducing graphite-based pencil material in polydimethylsiloxane (PDMS) matrix to fabricate a highly flexible composite film at an instant and economical base. The material choice was made on the presence of clay composed with Al and Si with abundance of graphite in pencil. After material synthesis, well-grinded pencil material (PM) was taken for composite film synthesis. Fabricating 175-μm-thick film by embedding 2 wt.% of PM in PDMS matrix, open-circuit voltage, short-circuit current of 87 V, 13 μA were measured, respectively. Furthermore, changing the top tribomaterial from aluminum to nylon, electrical output of the device was improved up to 53% open-circuit voltage and 31% short-circuit current. The obtained results of PM/PDMS membrane were compared with graphite/PDMS composite film. Furthermore, the composite membrane was employed for temperature-sensing application. The output of the membrane at different temperatures confirmed the robustness of the film for the cost-effective fabrication of a temperature-sensing device.