ABSTRACT Ceramic capacitors are critical components in advanced electronic devices, primarily due to their multi‐functionalities in energy/information storage and conversion. However, poor temperature stability remains a long‐standing challenge for practical applications, especially at extremely high‐ or low‐temperature conditions (e.g., > 200°C or < −55°C). In this work, we propose to combine the advantages of paraelectric Ba 0.3 Sr 0.7 TiO 3 (BST) with low Curie temperature and relaxor ferroelectric Bi 0.325 Na 0.325 Ba 0.105 Sr 0.245 TiO 3 (BNBST) with high dielectric constant using the spark plasma sintering (SPS) method, aiming to achieve a high and relatively stable dielectric constant over a wide temperature range. The BNBST‐0.6BST ceramics exhibit excellent dielectric properties: an ultrahigh dielectric constant of 3912 with the change of less than ± 15% over an ultrawide temperature range from −90°C to 400°C, significantly exceeding the standard of X9R. Additionally, the BNBST‐0.6BST ceramics also achieve a recoverable energy storage density of 3.5 J cm −3 under a moderate electric field of 270 kV cm −1 , with excellent stability and reliability. This work demonstrates the potential application of high dielectric constant BNT‐based ceramics over an ultrawide temperature range, driving the development of ceramic capacitors in extremely harsh service environments.
Li et al. (Sun,) studied this question.