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

Mauro Giorcelli,Alberto Tagliaferro,Elisa Padovano,Massimo Rovere,Mattia Bartoli,Carlo Rosso,Alessandro Sanginario

doi:10.1021/acsaelm.0c00971

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 103 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.

Highlights

During the last decades, biochar has attracted the interest of the scientific community for soil and fuel applications[1,2] and as a carbonaceous source for high value-added cost applications
Pristine biochar produced at 400 °C and thermally annealed olive biochar (TAOB) were first
We reported for the first time the use of thermally annealed biochar for the production of a fully reversible silicon-rubber piezoresistive material

Summary

Introduction

Biochar has attracted the interest of the scientific community for soil and fuel applications[1,2] and as a carbonaceous source for high value-added cost applications. By combining the low cost and a reduced environmental footprint, biochar is a strong candidate to become the carbon source for a new era of materials science.[3] Since the pioneering works of Das and co-workers,[4,5] biochar has proven itself an extremely sound choice for toughening a wide range of both the thermoset and thermoplastic polymeric matrix.[6−11] Khan et al.[12,13] used biochar as a replacement for traditional highperformance carbon fillers such as CNTs reaching better mechanical performances. The use of temperature up to 1000 °C leads to a dramatic increase in electrical conductivity due to the formation and reorganization through turbostratic rearrangement[23] of the graphitic domains as described by Eom et al.[24]

Methods

Results

Conclusion