High-Temperature Annealed Biochar as a Conductive Filler for the Production of Piezoresistive Materials for Energy Conversion Application

Abstract

In this research work, we develop a prototype that is able to convert mechanical strain into an electrical signal. To reach this scope, we evaluated the electrical properties of a thermally annealed biochar-based silicon composite. The great elasticity range of silicon will provide the mechanical properties for the realization of an effective piezoresistive material. For the fulfillment of this aim, we annealed olive biochar at 1500 °C in order to achieve a good degree of graphitization and an electrical conductivity close to 10 3 S/m. The electrical conductivity under the mechanical stress of composites was deeply investigated through experiments and simulation to achieve a comprehensive knowledge. Furthermore, a real device based on these composites was designed and realized to demonstrate one of the prospective exploitations of the composite piezoresistive properties.

Pressure-Responsive Conductive Poly(vinyl alcohol) Composites Containing Waste Cotton Fibers Biochar

“…As shown in Figure 4 b, the normalized conductivity shows very close trends for each curve, suggesting that the absolute value trends were mainly due to the amount of filler. The higher values of conductivity observed here, compared with previous work based on biochar produced in the same conditions, were reasonably due to both the favorable aspect ratio displayed by the deformed cylindrical morphologies [22,31,44].…”

“…Giorcelli et al [22] produced a piezoresistive device based on an annealed biochar containing silicon composites with remarkable response to pressure. Similarly, Nan et al [23] produced a reversible pressure-responsive biochar containing a poly(vinyl alcohol) (PVA) composite whose response was affected by filler percentage, thickness, and working temperature.…”

High Frequency Electromagnetic Shielding by Biochar-Based Composites

“…These analyses clearly show a material not yet fully graphitized but presenting an appreciable amount of graphitic domains. As reported in Reference [ 41 ], the carbon structure of biochar treated at 1500 °C was characterized by a high conductivity and could be easily used to improve the conductivity of related composites. Most likely, this increased conductivity (given by a combination of migration and hopping conductance [ 25 ] promoted by the ordering of graphitic crystallites), together with interfacial polarization [ 42 ], is the main mechanism contributing to EM shielding in biochar composites at these frequencies [ 43 ].…”

A Comprehensive Review on Raman Spectroscopy Applications

“…Accordingly, pyrolytic carbon could be described as a very highly defective graphitic material. The evolution of G and D peaks could be used to investigate the temperature used for the pyrolytic conversion of polymeric feedstock [119][120][121][122][123][124], but also to evaluate the different feedstock used for the production of carbon [125]. The main issue related to the interpretation of pyrolytic disordered carbon is represented by the fitting procedure that is affected by the uncertainty in the number and the lineshape of the components used.…”