NaNbO₃‐Based Multilayer Ceramic Capacitors with Ultrahigh Energy Storage Performance

Abstract With the gradual promotion of new energy technologies, there is a growing demand for capacitors with high energy storage density, high operating temperature, high operating voltage, and good temperature stability. In recent years, researchers have been devoted to improving the energy storage properties of lead‐based, titanium‐based, and iron‐based multilayer ceramic capacitors (MLCCs). However, limited research has been conducted into MLCC development using NaNbO 3 (NN)‐based materials. In this paper, the successful achievement of excellent overall energy storage performance in a novel NaNbO 3 –(Bi 0.5 Na 0.5 )TiO 3 –Bi(Mg 0.5 Hf 0.5 )O 3 lead‐free MLCCs is presented. The disordered tilting around the c p axis, disrupts Na and Bi ions' long‐range displacements and induces PNRs and strong relaxor behavior, which ensures a superior energy storage performance, together with the multilayer ceramic design strategy. As a result, the NN‐based MLCC device presents an ultra‐high W rec = 12.65 J cm −3 and η = 88.5%, simultaneously showing superior temperature stability ( W rec varies <±1% and η varies <±6% from −50 to 125 °C) and fatigue resistance ( W rec and η vary <±1% over 10 7 cycles). This study highlights the advanced energy storage potential of NaNbO 3 ‐based MLCCs for various applications, and ushers in a new era for designing high‐performance lead‐free capacitors that can operate in harsh environments.