Improved energy storage performance of NBTM/STM multilayer films via designing the stacking order

Abstract

In recent years, the demand for renewable energy has accelerated the development of advanced energy storage devices. Among various types of capacitors, dielectric capacitors have garnered significant attention due to their high power density, rapid charging and discharging capabilities, and excellent thermal stability. However, achieving high energy storage densities remains a challenge for broader applications. This work explores the energy storage performance of multilayer films composed of 1% Mn-doped Na_0.5Bi_0.5TiO₃ (NBTM) and 1% Mn-doped SrTiO₃ (STM). Several multilayer structures have been constructed by varying the stacking order of NBTM and STM layers on Pt/Ti/SiO₂/Si substrates via the sol–gel method. The impact of the number of interfaces on polarization performance and breakdown strength was systematically investigated. The optimized 2NBTM/STM/2NBTM/STM/2NBTM (2N/S/2N/S/2N) film exhibited remarkable improvements in both polarization and breakdown strength, achieving a recoverable energy storage density (W_rec) of 68.9 J cm⁻³ and a breakdown strength (E_b) of 4300 kV cm⁻¹. Additionally, the film exhibits excellent temperature stability (20–200 °C), frequency stability (500–5000 Hz), and maintained the energy storage performance even after 10⁷ electrical cycles. These results highlight the potential of interface engineering in enhancing the energy storage properties of dielectric capacitors.