Superior Energy Storage Properties and Optical Transparency in K<sub>0.5</sub>Na<sub>0.5</sub>NbO<sub>3</sub>‐Based Dielectric Ceramics via Multiple Synergistic Strategies
Qizhen Chai, Fudong Zhang, Qiyuan Zhou, Zhanhui Peng, Di Wu, Pengfei Liang, Lingling Wei, Xiaolian Chao, Zupei Yang
Abstract
Abstract Eco‐friendly transparent dielectric ceramics with superior energy storage properties are highly desirable in various transparent energy‐storage electronic devices, ranging from advanced transparent pulse capacitors to electro‐optical multifunctional devices. However, the collaborative improvement of energy storage properties and optical transparency in KNN‐based ceramics still remains challenging. To address this issue, multiple synergistic strategies are proposed, such as refining the grain size, introducing polar nanoregions, and inducing a high‐symmetry phase structure. Accordingly, outstanding energy storage density ( W total ≈7.5 J cm −3 , W rec ≈5.3 J cm −3 ) and optical transmittance (≈76% at 1600 nm, ≈62% at 780 nm) are simultaneously realized in the 0.94(K 0.5 Na 0.5 )NbO 3 ‐0.06Sr 0.7 La 0.2 ZrO 3 ceramic, together with satisfactory charge‐discharge performances (discharge energy density: ≈2.7 J cm −3 , power density: ≈243 MW cm −3 , discharge rate: ≈76 ns), surpassing previously reported KNN‐based transparent ceramics. Piezoresponse force microscopy and transmission electron microscopy revealed that this excellent performance can be attributed to the nanoscale domain and submicron‐scale grain size. The significant improvement in the optical transparency and energy storage properties of the materials resulted in the widening of the application prospects of the materials.