Enhancing energy storage performances in an ultra-wide temperature range via interface engineering and thermal management for silicon-integrated dielectric capacitors

High-performance silicon-integrated dielectric thin film capacitors with superior thermal stability are strongly attractive for application in integrated circuits and electronic devices. Here, by combining interface engineering with thermal management, lead-free 0.85BaTiO3-0.15Bi(Mg0.5Zr0.5)O3 (BT-BMZ) dielectric thin film capacitors were integrated on Si, HfO2-buffered Si (HfO2/Si), and graphene-buffered HfO2/Si (G/HfO2/Si) substrates. Benefiting from not only high-quality interface between HfO2 and Si but also the heat dissipation effect of the graphene layer, an ultra-high energy storage density up to 102 J/cm3 with an efficiency of 74.57% was obtained in BT-BMZ/G/HfO2/Si at room temperature. More importantly, the optimized capacitor exhibited an ultra-stable energy density of 52.1 J/cm3 (±10%) with high efficiency (over 70%) in a wide temperature range of -100 to 175 °C, greatly broadening the working temperature in comparison to BT-BMZ/Si (-100 to 100 °C). The present research provides a scalable strategy to enhance energy storage performance of dielectric capacitors, especially at elevated temperatures.