Dielectric capacitors, storing energy with the aid of dielectric polarization, are widely applied in a broad variety of advanced electronic systems due to their ultrafast discharge rates, ultrahigh power densities, and excellent chemical stabilities. (Bi0.5Na0.5)0.7Sr0.3TiO3 (BNST)-based relaxor ferroelectric ceramics were prepared through new material design and component optimization strategies. (1-x)BNST-xCT ceramics show the excellent energy storage properties (high Wrec of ~7.00 J/cm3, large  of ~90.90%, and ultrahigh of Eb ~660 kV/cm). The intrinsic and extrinsic origins of enhanced energy storage properties are illustrated from different scales