Enhanced energy storage performances of CaTiO3-based ceramic through A-site Sm3+ doping and A-site vacancy

Ceramic-based capacitors for energy storage devices require simultaneously high energy density and efficiency. Achieving high electric breakdown field based on linear dielectrics is crucial. Here, A-site Sm 3+ doped perovskite Ca 1-1.5 x Sm x □ 0.5 x TiO 3 ceramics with introduced A-site vacancies ( V A ) were prepared. All Ca 1-1.5 x Sm x □ 0.5 x TiO 3 ceramics crystallize in an orthorhombic structure, with lattice constants a , b , and c linearly decreased. As a result of Sm 3+ dopants and V A , the grain size decreased while the ceramics’ density was improved. The permittivity decreases from 176 ( x = 0) to 135 ( x = 0.1), but tan δ is effectively constrained (∼10 −4 ). What’s more, the dielectric breakdown strength is significantly improved from 429 kV/cm ( x = 0) to 547 kV/cm ( x = 0.1) with dielectric linearity is maintained. The optimum energy storage density of 2 J/cm 3 ( x = 0.02) with ultrahigh energy efficiency of over 93.7 % is achieved, which are superior to many existing linear dielectrics and relaxor ferroelectrics. This work confirms the energy-storage enhancement through chemical modifications and microstructural engineering.