Lead-free Nb-based dielectric film capacitors for energy storage applications

Dielectric capacitors are the ideal energy storage devices because they have excellent power density, high working voltages, and a long lifespan. With its lower size and better energy storage density, film capacitors make them simpler to incorporate into circuits than traditional dielectric capacitor devices. Lead-free Nb-based perovskite ferroelectric/antiferroelectric films have strong orbital hybridization with O 2p orbitals due to unfilled d orbitals of Nb elements, forming a series of energy storage film materials with potential application value. Here, we provide an overview of the state-of-the-art lead-free Nb-based films for energy storage applications, which include K0.5Na0.5NbO3-based, K0.5Na0.5Bi4NbTi3O15-based, AgNbO3-based and NaNbO3-based films. An overview of the benefits and drawbacks of each kind of Nb-based perovskite ferroelectric/antiferroelectric films is provided, along with a description of the design tactics used to achieve high energy storage performances.