Lead-free dielectric ceramics with ultrahigh energy-storage performance are the core components used in next-generation advanced pulse power capacitors. However, the low energy storage density largely hinders their development towards miniaturization, lightweight, and integration. Here, an effective strategy of constructing local diverse polarization is designed in superparaelectrics to realize an ultrahigh energy storage density of ≈10.59 J cm-3 as well as a large efficiency of ≈87.6%. The excellent comprehensive energy-storage performance is mainly attributed to the design of ultrasmall polar nanoregions with local diverse polarization configuration, confirmed by scanning transmission electron microscopy, leading to the reduced heat loss, substantially enhanced polarization, and breakdown electric field compared to ceramics with single polarization configuration. Benefiting from these features, outstanding temperature/frequency/cycling stability and superior charge/discharge performance (power density ≈187.5 MW cm-3 , discharge energy density ≈3.52 J cm-3 , discharge rate ≈77 ns) are also achieved. This work demonstrates that local diverse polarization is a super strategy to design new dielectric materials with high energy-storage performance.
Keywords: energy storage; lead-free dielectric ceramics; local diverse polarization; relaxor ferroelectrics; superparaelectrics.
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