Amelioration on energy storage performance of KNN‐based transparent ceramics by optimizing the polarization and breakdown strength

Abstract Transparent ceramic capacitors have broad application prospects in electronic devices due to their excellent optical transparency and energy storage properties. However, the low polarizability and high remnant polarization of the existing transparent dielectric ceramics limit the promotion of energy storage performance. Here, Bi(Li 0.5 Nb 0.5 )O 3 (BLN) was chosen to modify the (K 0.5 Na 0.5 )NbO 3 (KNN)‐based ceramics to optimize the optical transmittance and energy storage characteristics simultaneously. On the one hand, the grain growth is inhibited, contributing to the improved breakdown strength and transmittance. On the other hand, the doping BLN could reduce the polar nanoregions size, which makes them respond more quickly to the external electric field and, thus, improves the energy storage efficiency. As a consequence, 0.95KNN–0.05BLN ceramic possesses the excellent W rec of 4.39 J/cm 3 , η of 81.4%, and transparency of 77.9% with an average grain size of ∼109 nm. This work opens up a paradigm to develop a transparent pulse capacitor.