Energy harvesting in core-shell ferroelectric ceramics: Theoretical approach and practical conclusions

We have made a quantitative evaluation of the possibility to store electrical energy using ferroelectric supercapacitor built on core-shell nanoceramics. We have first solved the Laplace equation for a single core-shell particle and used afterward an effective medium approximation to get in a self consistent way the equations for the different internal electric field, the permittivity and the polarization of a nanoceramic constituted of such core-shell particles. A numerical calculation was performed to check these results. We could generalize these results in the case of a ceramic made of core-n shells particles, and for different cases of anisotropic shapes of particles. We have introduced afterward the expression of the core-shell polarization into the Landau potential for nanoceramics by Li et al. [J. Appl. Phys. 98, 064101 (2005)] which allows us to get the phases diagrams for different cases of nanoparticles shapes. Numerical minimization of the Landau potential results in curves of polarization ver...