BCZT/LSMO/BCZT multilayer films for high temperature energy storage capacitors

Abstract: Ba0.85Ca0.15Zr0.1Ti0.9O3/La0.8Sr0.2MnO3/Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT/LSMO/BCZT) sandwich films were elaborated using the sol-gel spin coating process. The dielectric properties displayed excellent thermal stability with the temperature coefficient of capacitance, TCC, remaining within 10% between -50 C and 300 C. The high energy storage density, Wrec, of 11.8 J/cm3 observed in this sandwich films, is nearly twice as high as that of the BCZT films, with an efficiency, n, of 77% under a weak electric field of 800 kV/cm. Furthermore, the stability of Wrec and n was observed along the studied temperature interval making them promising candidates for high-temperature energy storage capacitors.

• The paper presents BCZT/LSMO/BCZT multilayer films that significantly enhance energy storage density and thermal stability compared to traditional designs.
• The authors utilized a sol-gel spin-coating process and comprehensive structural techniques like XRD and SEM to confirm the perovskite phase and uniform microstructure.
• The multilayer films achieved an energy density of 11.8 J/cm³ and 77% efficiency under 800 kV/cm, making them promising for high-temperature applications.

BCZT/LSMO/BCZT Multilayer Films for High-Temperature Energy Storage Capacitors

Introduction

The study of energy storage materials suitable for high-temperature applications is pivotal in addressing the increasing energy demands of modern technologies. The exploration of BCZT/LSMO/BCZT multilayer films denotes a substantial step forward in advancing dielectric capacitors with improved thermal stability and energy storage capabilities. Utilizing a sol-gel spin-coating process, these films demonstrate significant promise due to their exceptional energy density and operational stability across a broad temperature range. This paper examines the synthesis, characterization, and performance metrics that underscore the viability of these multilayer films for use in high-temperature applications.

Synthesis and Structural Characterization

The BCZT/LSMO/BCZT multilayer films were prepared using the sol-gel spin-coating method and deposited onto Pt/TiO2/SiO2/Si substrates. The X-ray diffraction (XRD) patterns affirm the presence of a perovskite phase, vital for the desired ferroelectric properties. Scanning Electron Microscopy (SEM) images reveal a homogeneous microstructure with a fine grain size distribution. Distinct from simple BCZT and LSMO films, the multilayer structure exhibits enhanced smoothness and uniformity due to the intercalated LSMO layer. The dielectric constant stability in these multilayers is critical in supporting the perovskite phase's energy storage potential.

Thermal Stability and Dielectric Properties

A defining feature of the BCZT/LSMO/BCZT films is their excellent thermal stability, with the temperature coefficient of capacitance (TCC) remaining within ±10% from -50°C to 300°C. The dielectric constant is maintained with minimal variation across this wide temperature span, contrasting significantly with traditional X7R capacitors which operate effectively between -55°C and 125°C. This stability is primarily attributed to the Maxwell-Wagner polarization effect at the interfaces of the layers, facilitated by the charge transport properties of LSMO. This result establishes an advancement in extending the operational temperature range of energy storage materials.

Energy Storage Performance

The recoverable energy density ($W_{rec}$) and efficiency ($\eta$) of the BCZT/LSMO/BCZT films are notable at 11.8 J/cm³ and 77%, respectively, under an electric field of 800 kV/cm. These films demonstrate nearly double the energy density of comparable BCZT-only films, highlighting the benefits of integrating the LSMO layer. Furthermore, the energy storage properties exhibit remarkable consistency across a temperature range up to 300°C, with efficiency consistently surpassing 75%. This thermal stability and enhanced energy density position the BCZT/LSMO/BCZT films as leading candidates for high-temperature energy storage applications.

Comparative Analysis and Future Directions

When compared with other lead-free thin films, the BCZT/LSMO/BCZT multilayer films show superior performance, particularly in retaining high energy density at elevated temperatures and under low applied electric fields. The innovative approach of embedding a single LSMO layer contributes significantly to this effect, optimizing the dielectric and ferroelectric properties necessary for high-efficiency energy storage. Future research could focus on further optimizing the structural properties and exploring additional material combinations to enhance energy storage efficiency further. Such advancements will undoubtedly contribute to the evolving landscape of high-performance energy storage materials suitable for extreme conditions.

Conclusion

The BCZT/LSMO/BCZT multilayer films exhibit a compelling combination of thermal stability, high energy density, and efficiency, distinguishing them as prime candidates for next-generation high-temperature dielectric capacitors. Their successful implementation could notably expand the capabilities of energy storage in advanced electronic systems, pulsed power systems, and other applications requiring robust performance under stringent thermal conditions. This study advances the understanding of ferroelectric multilayers and opens avenues for further innovations in high-temperature energy storage technologies.