Achieving comprehensive temperature-stable energy storage properties in core-shell Na0.4K0.1Bi0.5TiO3@(SrZrO3-BiMg0.5Sn0.5O3)@SiO2 ceramics via a multi-scale synergistic optimization

At present, to improve the energy storage properties and wide-range temperature stability synergistically is the bottleneck of Na0.5Bi0.5TiO3 (NBT)-based energy storage ceramics. In this paper, it is expected to breakthrough this bottleneck through a multi-scale synergistic optimization (including composition, structure and preparation) integrated by the design of core–shell structure. This unique structure is constructed by coating SrZrO3-BiMg0.5Sn0.5O3 (SZ-BMS) on the surface of Na0.4K0.1Bi0.5TiO3 (NKBT), and then coating SiO2 glass to prepare NKBT@(SZ-BMS)@SiO2 ceramics. The SZ-BMS phase plays multi roles in alleviating interfacial polarization, domain reconstruction and defect regulation. The outer SiO2 layer benefits to grain size refinement and defect control. The energy storage performance of NKBT@(SZ-BMS)@SiO2 ceramics are affected by the BMS amount. When the BMS amount is 15 mol%, high breakdown strength of 301 kV/cm and polarization of 29.1 μC/cm2 are achieved in the ceramics. Ultimately, large recoverable energy density of 3.94 J/cm3 with high efficiency of 87.1% are simultaneously obtained. It also has an ultra-wide temperature stability (30–467 ℃) of dielectric properties and excellent thermal endurance of energy storage within 20–150 ℃. The prepared NKBT@(SZ-BMS)@SiO2 ceramic is a favorable alternative for temperature-stable energy storage capacitors.