Design and Development of a Fully Sustainable Piezoelectric Energy Harvester from Bio Waste Prawn Shell

In this work, a biocompatible and fully sustainable, self-poled green energy harvester is designed from the exoskeleton of prawn fish. The prawn shells (PS) are collected from the biowaste of a local seafood processing plant. Shell surfaces are properly cleaned with DI water to remove any loose debris or contaminants. A strong chelating agent Ethylenediaminetetraacetic acid (EDTA), that can effectively bind to metal ions is used to remove the mineral content and metal ions from the shell surface. Any trapped water content on the PS surfaces is dissipated by keeping the sample at room temperature for 24 hours. The PS contains 20%–50% calcium carbonate, 20%–40% protein and 15%–40% chitin, where the chitin nano fiber act as an active piezoelectric element. X-ray diffraction peak obtained at 2θ° =9.24° and 19.4° confirms the presence of crystalline intersheet α-chitin and intrasheet β-chitin that possess piezoelectric properties and contributes inherently to piezoelectricity of PS. The (PS) energy harvester of a very small surface area of “10 mm X 8 mm ” fabricated as silver-prawn shell-silver layer, generates 480 mV open circuit output voltage only by finger taping longitudinally on its surface. Optimizing the electrical load, the piezoelectric generator can generate 470 mV output across 500 kΩ and harvest 441.8 nW of output power at applied mechanical stress only by finger taping at 2 Hz.