Ultra-high energy storage in relaxor ferroelectric MLCCs at elevated temperatures via entropy modulated strain heterogeneity.

Multilayer ceramic capacitors are pivotal components in pulse power systems due to their ultra-high power density. However, given the demanding service conditions in aerospace and oil drilling applications, the need to enhance high-temperature energy storage remains particularly urgent. In this work, we employ a strain modulation strategy by enhancing configuration entropy within bismuth sodium titanate-based ceramics. This approach enhances relaxor behavior, suppresses electron migration, and improves structural stability and breakdown strength at elevated temperatures. Notably, the resulting multilayer ceramic capacitors exhibit a substantial recoverable energy density of 19.0 J cm-3 and an impressive efficiency of 90% under an electric field of 1320 kV cm-1. Furthermore, these capacitors sustain a high energy density above 11.0 J cm-3 even at 200 °C. This extraordinary high-temperature energy storage performance surpasses those of recently reported multilayer ceramic capacitors. Our findings underscore the significant potential of strain modulation as a strategy for designing high-temperature energy storage materials.