Enhanced figure-of-merit and fatigue resistance of strontium barium niobate for pyroelectric energy conversion

Abstract

Pyroelectric energy conversion shows potential for low-grade waste heat harvesting. In this work, we design and investigate the SrxBa1−xNb2O6 material at x = 0.6 (SBN60), focusing on the role of oxygen vacancies and their impacts on pyroelectric performance. By employing floating-zone synthesis with proper heat-treatment process, we systematically tune oxygen vacancies and reveal their dual effect: oxygen vacancies enhance the pyroelectric figure-of-merit, while removing oxygen vacancies extends the effective lifetime in one-charge pyroelectric energy conversion. We discover that the phase transition in a heat-treated single crystal SBN60 device helps achieve stable electricity generation for approximately 7000 cycles in 30 h with enhanced functional reversibility. The dual effect of oxygen vacancies on the coupling of pyroelectricity and effective lifetime provides a useful strategy to design high-performance pyroelectric materials, especially for one-charge pyroelectric energy conversion, offering a practical solution for real-world applications of pyroelectric devices.