High Temperature-Insensitive Electrostrain Obtained in (K, Na)NbO₃-Based Lead-Free Piezoceramics

Area of Science:

• Materials Science
• Ceramics Engineering
• Solid State Physics

Background:

• Significant advancements in lead-free (K, Na)NbO3 (KNN)-based piezoceramics have been made.
• Enhancing piezoelectric charge coefficient (d33) and electric-field induced strain remains crucial for actuator applications.
• High temperature stability is essential for reliable performance across diverse operating conditions.

Purpose of the Study:

• To develop Li/Sb-codoped KNN (LKNNS) ceramics with enhanced electrostrain and temperature stability.
• To investigate the roles of defect engineering and domain engineering in optimizing piezoelectric properties.
• To provide a design model for high-performance piezoelectric materials.

Main Methods:

• Synthesized Li/Sb-codoped KNN (LKNNS) ceramics.
• Employed defect engineering and domain engineering strategies.
• Characterized piezoelectric properties, including electric-field induced strain and d33*, across a wide temperature range.

Main Results:

• Achieved a remarkable strain of 0.43% and a giant d33* value of 2177 pm V-1 at 20 kV cm-1.
• Demonstrated minimal performance decrease (<15%) from room temperature to 150 °C.
• Attributed high electrostrain to A-site vacancy-oxygen vacancy defect dipoles and increased nano-domains.

Conclusions:

• The developed LKNNS ceramics exhibit excellent overall performance for actuator applications.
• Hierarchical domain configuration and defect dipoles contribute to exceptional temperature stability.
• This work offers a model for designing advanced piezoelectric materials with superior strain and thermal resilience.