Significant improvement of comprehensive energy storage performance and transparency in Sr0.7La0.2TiO3-doped (K,Na)NbO3 lead-free ceramics

Abstract

Although transparent ceramics are highly desirable for practical applications, it is challenging to achieve outstanding energy storage properties and high transparency simultaneously in (K, Na)NbO3 ceramics. Herein, through a combination of modifying crystal symmetry and refining domain size and grain size, a high recoverable energy storage density Wrec ≈ 4.04 J cm−3, a high efficiency η ≈ 73 %, and good optical transmittance (≈ 77 % at 2000 nm, ≈ 60 % at 780 nm) are realized. Of particular significance is that an excellent discharge energy density of ≈ 2.43 J cm−3, a superior discharge current density of ≈ 1551 A cm−2, and a high discharge power density of ≈ 233 MW cm−3 are simultaneously achieved in 0.93(K0.5Na0.5)NbO3-0.07 Sr0.7La0.2TiO3 ceramics, outperforming all reported KNN-based transparent ceramics. This work exhibits a paradigm for achieving high performance KNN-based ceramics, and the transparent dielectric ceramics reported here are expect to expand hybrid electronic device applications.