Life Cycle Assessment of Piezoelectric Materials Used for Energy Harvesting Systems: PZT Versus KNN

Over the past decade, piezoelectric materials have been extensively used in various engineering areas, particularly for energy harvesting, due to their efficient electromechanical conversion. Several scientific researches reported in the literature have performed modeling, prototyping, and experimentation to improve the performance of harvesters. Piezoelectric transducers, especially those used for energy harvesting, could have significant environmental impacts. Few studies have emphasized the environmental issue of harvesters in their life cycle. This paper aims to study the environmental impacts of piezoelectric energy harvesters obtained with screen-printing process by performing a life cycle assessment (LCA). Firstly, a comprehensive overview of piezoelectric materials and their implementation in the context of micro electromechanical systems is first presented. Secondly, the environmental impacts of these materials are briefly discussed based on previous studies. Here the aim is to present a comparative analysis of the environmental consequences of energy harvesters based on different piezoelectric materials, from cradle to gate. The harvester based on lead zirconate titanate Pb(Zr,Ti)O3 (PZT) is taken as a reference. The impact assessment is conducted by evaluating the selected impact categories using ILCD 2011 method. Results highlight the most impactful components of energy harvesters referring to the unique scores calculated for different impact categories at the Midpoint. They highlight also the importance of LCA and offer technical guidance and crucial recommendations for eco-design.