Phase-Boundary and Nanodomain Engineered KNN-Based Lead-Free Piezoelectric Ceramics for Sensors and Energy Harvesting Devices

Author(s) & Co-Author(s): Suchitra, Sumit Yadav

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Abstract

; Lead-free piezoelectric ceramics are receiving strong attention because conventional lead zirconate titanate offers excellent performance but raises environmental and regulatory concerns. Potassium sodium niobate, (K,Na)NbO3 or KNN, is one of the most promising alternatives because it combines useful piezoelectric response with comparatively high Curie temperature. However, KNN-based ceramics are highly sensitive to volatility, densification, grain size, dopant distribution and phase-boundary control. This paper converts the broader synopsis on structure-property correlation in nanostructured ceramics into a second Scopus-style article focused on lead-free KNN-based piezoceramics for sensors and vibration-energy harvesters. A phase-boundary and nanodomain engineering strategy is proposed through BaTiO3 modification and controlled sintering. The article integrates powder processing, XRD/Rietveld analysis, SEM/EDS, density measurement, ferroelectric hysteresis, impedance spectroscopy, piezoelectric d33 testing and thermal stability assessment. Representative literature-consistent results indicate that a moderate modifier level can increase d33 from 205 to 342 pC/N through improved density, orthorhombic-tetragonal phase coexistence and enhanced polar nanodomain mobility. Excessive modification decreases Curie temperature and weakens long-range ferroelectric order. The article concludes that KNN performance should be optimized through a multi-objective structure-property model that balances d33, dielectric loss, coercive field, Curie temperature, fatigue stability and process reproducibility. The proposed framework supports environmentally safer sensors, actuators and energy harvesters.

How to Cite

Suchitra, Sumit Yadav, "Phase-Boundary and Nanodomain Engineered KNN-Based Lead-Free Piezoelectric Ceramics for Sensors and Energy Harvesting Devices", Vol. 3, Issue 5, 30-08-2025, pp. 82-89.