Heterogeneous weakly coupled polar nanoclusters enabling superior high-temperature capacitive energy storage

Ceramic capacitors, although promising for advanced high-power energy storage, face challenges in energy density and efficiency at high temperatures, which restricts their practical applications. Guided by phase field simulations, we propose a structural design strategy to construct weakly coupled polar nanoclusters in superparaelectric state, and fabricate BaTiO₃-based multilayer ceramic capacitors via prototype device technology. The capacitors achieve an ultrahigh energy storage density of 19.0 J·cm^-3 and a high energy storage efficiency of 95.5% at room temperature. More importantly, both metrics are still on the order of > 10.0 J·cm^-3 and > 95.0%, respectively, over 25-160 ^oC, outperforming previously reported ceramic capacitors. The weaken coupling between adjacent nanoclusters caused by disordered polar configurations, suppresses nonlinear polarization response and temperature sensitivity, ultimately enabling superior energy storage performance, which is confirmed by atomic-scale microstructure analysis. This work advances next-generation electronics and provides insights for developing high-performance high-temperature ceramic capacitors.