In the relentless pursuit of materials that can withstand the harsh conditions of high-temperature environments, researchers have long sought to enhance the performance of piezoelectric ceramics. These materials, which convert mechanical stress into electrical energy and vice versa, are crucial for various applications, including energy harvesting and high-temperature sensing. A recent breakthrough by Changbai Long and his team at the State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, China, has brought us one step closer to achieving this goal.
The team focused on Aurivillius phase CaBi2Nb2O9 (CBNO) ceramics, known for their ultrahigh Curie temperature of approximately 934°C. This property makes them ideal for high-temperature applications, but their low piezoelectricity and poor electrical insulation have hindered their practical use. Long and his colleagues tackled these challenges head-on, developing a multi-field coupling strategy that significantly boosts the performance of CBNO ceramics.
The strategy involves introducing Li/Pr and Bi/Sc doping, which creates lattice stress and electric fields that optimize the ceramic’s piezoelectric properties, electrical conduction behavior, and temperature stability. “The constructed lattice stress and electric fields induced by introducing Li/Pr and Bi/Sc doping have great impacts on the lattice structure, microstructure, domain structure and defect chemistry,” Long explains. This results in a significant increase in piezoelectric activity (d33) due to enhanced polarization, improved breakdown electric field, and the production of nanoscale domains.
The researchers achieved a high d33 of approximately 18.2 pC/N in the designed Ca1–3x (Li0.5Pr0.5)xBi2+2xNb2–xScxO9 system, with an ultrahigh Curie temperature of approximately 938°C. This breakthrough is complemented by high electrical resistivity (ρ∼1.72 MΩ⋅cm at 600°C) and nearly stable d33 up to 800°C, making it a promising material for high-temperature sensing applications.
The implications of this research are vast, particularly for the energy sector. High-temperature piezoelectric materials are essential for energy harvesting in extreme environments, such as geothermal power plants and industrial furnaces. The enhanced performance of CBNO ceramics could lead to more efficient and reliable energy harvesting systems, reducing costs and improving sustainability.
Moreover, the multi-field coupling strategy developed by Long and his team opens new avenues for optimizing other piezoelectric materials. By understanding and manipulating the interactions between lattice stress, electric fields, and defect chemistry, researchers can tailor materials for specific applications, pushing the boundaries of what is possible in high-temperature piezoelectric technology.
The study, published in the Journal of Materiomics (translated to English as ‘Journal of Material Science’), marks a significant milestone in the field. As the demand for high-temperature piezoelectric materials continues to grow, this research paves the way for future developments, inspiring further innovation and discovery.
