High‐Energy Storage Density and Efficiency of the xBi(Mg2/3Nb1/3)O3‐(1 − x)(Ba0.8Sr0.2)TiO3 (0.08 ≤ x ≤ 0.14) Lead‐Free Perovskite Structured Ceramics

The compounds x Bi(Mg 2/3 Nb 1/3 )O 3 ‐(1 − x )(Ba 0.8 Sr 0.2 )TiO 3 ( x BMN‐(1 − x )BST, 0.08 ≤ x ≤ 0.14) are prepared via the traditional solid‐state reaction method and the ceramics are well densified in the sintering temperature range of 1280–1330 °C. X‐ray diffraction analysis shows that all the ceramics crystallize into perovskite structure. Proper amounts of BMN additions can effectively reduce grain sizes of the x BMN‐(1 − x )BST ceramics, resulting in more uniform microstructures. Accordingly, breakdown strength E b is improved and a maximum value 250 kV cm −1 is obtained in ceramic with x = 0.10. Meanwhile, recoverable energy storage density W rec of the 0.1BMN‐0.9BST ceramics reaches 2.03 J cm −3 , and energy storage efficiency ( η ) is 96.8%. When the operating temperature increases to 150 °C, the W rec and η values are about 1.02 J cm −3 under 150 kV cm −1 and 89.8%, respectively.