A novel lead-free and high-performance barium strontium titanate-based thin film capacitor with ultrahigh energy storage density and giant power density

High-performance lead-free film capacitors with simultaneously large energy storage density and high power density are strongly demanded in applications. Here, a novel relaxor-ferroelectric 0.88Ba(0.55)Sr(0.45)TiO(3)-0.12BiMg(2/3)Nb(1/3)O(3) (BST-BMN) thin film capacitor was obtained with an ultrahigh recoverable energy storage density (W-rec) of similar to 86 J cm(-3) and high efficiency of similar to 73% under the dielectric breakdown strength of 5 MV cm(-1). In addition, the investigated thin film capacitor exhibited an excellent fatigue resistance property with the W-rec variation less than similar to 2% after 10(7) cycles. More importantly, a considerable power density of similar to 208 MW cm(-3) was obtained in BST-BMN thin film capacitors, which is superior to many other thin film capacitors. These remarkable performances should be attributed to the simultaneously enhanced BDS and relaxor behavior through the incorporation of non-isovalent ions. These results qualify the environment-benign BST-BMN thin films as promising candidates for energy storage applications and promote the development of BST-based film capacitors with enhanced W-rec in the future.