Enhancing energy storage properties by engineering competing ferroic orders in NaNbO<sub>3</sub> thin films
ORAL
Abstract
Bulk NaNbO3 is an antiferroelectric that undergoes an irreversible transition to a ferroelectric with poor energy storage properties under applied electric field1,2. To find low-cost, lead-free materials for electrostatic energy storage applications, extensive work has been done to improve these properties by studying NaNbO3-based ceramic compositions where antiferroelectric or relaxor ferroelectric behaviors can be stabilized1,3. Concurrently, previous work in pure NaNbO3 thin films and membranes has demonstrated that epitaxial strain and thickness can be used to tune the phase stability of the ferroelectric and antiferroelectric. However, there has been limited electrical characterization of these systems due to large leakage currents.4-8
In this work, we study the thickness-dependent evolution of electrical and structural properties of epitaxially strained NaNbO3 thin films. Using pulsed laser deposition and selective etching, we synthesize La0.7Sr0.3MnO3/NaNbO3/La0.7Sr0.3MnO3 symmetric capacitor structures on SrTiO3(001) substrates. By optimizing growth conditions to minimize leakage, we obtain good ferroelectric hysteresis loops at large applied electric fields down to 35 nm films. While our thinnest films are purely ferroelectric, we observe a phase coexistence of ferroelectric and antiferroelectric phases at intermediate thicknesses that gives rise to a multi-state switching mechanism. We characterize the stable intermediate states and demonstrate their improved energy storage properties. Thus, we demonstrate how tuning film thickness and applied field can help achieve improved energy efficiencies and recoverable energy densities comparable to records in NaNbO3-based ceramic capacitors and significantly better than previously measured pure NaNbO3 systems1,7,8,.
[1] M.-H. Zhang et al., Nat. Comm. 14, 1525 (2023)
[2] M.-H. Zhang et al., Acta Mater. 200, 127-135 (2020)
[3] N. Luo et al., Nat. Comm. 14, 1776 (2023)
[4] T. Schneider et al., ACS Omega 8, 23587-23595 (2023)
[5] R. Xu et al., Adv. Mater. 35, 2210562 (2023)
[6] B. Lin et al., Nat. 633, 798-803 (2024)
[7] T. Shiraishi et al., J. Appl. Phys. 128, 044102 (2020)
[8] H. Dong et al., Ceram. Inter. 48, 16215-16220 (2022)
In this work, we study the thickness-dependent evolution of electrical and structural properties of epitaxially strained NaNbO3 thin films. Using pulsed laser deposition and selective etching, we synthesize La0.7Sr0.3MnO3/NaNbO3/La0.7Sr0.3MnO3 symmetric capacitor structures on SrTiO3(001) substrates. By optimizing growth conditions to minimize leakage, we obtain good ferroelectric hysteresis loops at large applied electric fields down to 35 nm films. While our thinnest films are purely ferroelectric, we observe a phase coexistence of ferroelectric and antiferroelectric phases at intermediate thicknesses that gives rise to a multi-state switching mechanism. We characterize the stable intermediate states and demonstrate their improved energy storage properties. Thus, we demonstrate how tuning film thickness and applied field can help achieve improved energy efficiencies and recoverable energy densities comparable to records in NaNbO3-based ceramic capacitors and significantly better than previously measured pure NaNbO3 systems1,7,8,.
[1] M.-H. Zhang et al., Nat. Comm. 14, 1525 (2023)
[2] M.-H. Zhang et al., Acta Mater. 200, 127-135 (2020)
[3] N. Luo et al., Nat. Comm. 14, 1776 (2023)
[4] T. Schneider et al., ACS Omega 8, 23587-23595 (2023)
[5] R. Xu et al., Adv. Mater. 35, 2210562 (2023)
[6] B. Lin et al., Nat. 633, 798-803 (2024)
[7] T. Shiraishi et al., J. Appl. Phys. 128, 044102 (2020)
[8] H. Dong et al., Ceram. Inter. 48, 16215-16220 (2022)
–
Presenters
-
Aarushi Khandelwal
Stanford University
Authors
-
Aarushi Khandelwal
Stanford University
-
Kevin J Crust
Stanford University
-
Reza Ghanbari
North Carolina State University
-
Ruijuan Xu
North Carolina State University
-
Harold Y Hwang
Stanford University