Utilizing ferrorestorable polarization in energy-storage ceramic capacitors

Abstract A self-powered system with a long lifetime would represent an opportunity in the development of a next-generation, standalone Internet of Things. Ceramic capacitors are promising candidates for energy storage components because of their stability and fast charge/discharge capabilities. However, even the energy density of state-of-the-art capacitors needs to be increased markedly for this application. Improving the breakdown electric field represents a potential solution, but operations at such high fields relying on unchanged dielectric permittivity sacrifice the lifetime of the capacitor to some degree. Here, we report ferrorestorable polarization engineering capable of more than doubling the effective permittivity. Our experiments and ab initio calculations demonstrate that a defect dipole composed of Cu ³⁺ and oxygen vacancy in a prototypical ferroelectric BaTiO ₃ ceramic is coupled with spontaneous polarization. The resultant ferrorestorable polarization delivers an extraordinarily large effective relative permittivity, beyond 7000, with a high energy efficiency up to 89%. Our work paves the way to realizing efficient ceramic capacitors for self-powered applications.