Remarkable capacitive performance in novel tungsten bronze ceramics

In this study, novel lead-free Sr_1.75Ca_0.25NaNb₅O₁₅ tungsten bronze ceramics were designed for potential energy storage applications. A remarkable energy storage density (∼3.23 J cm^-3) along with a high energy storage efficiency (∼88.2%) was obtained simultaneously at an applied electric field of 290 kV cm^-1. Moreover, the ceramic also showed exceptional discharging performance including a fast discharge rate (τ_0.9 < 70 ns), an ultrahigh discharge current density (1104 A cm^-2) and a high power density (82.8 MW cm^-3). The achieved capacitive performance in this work indicates the great potential of the designed novel tungsten bronze ceramic for energy storage applications.