Perovskite solid solution in the (1-x)[0.4BiScO(3)-0.6BaTiO(3)]+x (K1/2Bi1/2)TiO3 [BSBT-KBTx] system was synthesized using conventional sintering and hot-isostatic pressing. Dielectric properties of BSBT ceramics with different dopant levels of KBT were characterized as a function of temperature and frequency for potential use of high-temperature capacitors. The BSBT ceramics with KBT exhibited high dielectric permittivities (epsilon(r)) (> 1700 at RT) and low dielectric loss over the temperature range from 100 degrees to 300 degrees C, with flat temperature coefficients of permittivity (TC epsilon s). In addition, BSBT ceramics with increasing KBT were observed to possess dielectric relaxation characteristics at temperatures (> RT) as observed in lead-based relaxors. Furthermore, high energy densities, being on the order of 4.0 J/cm(3) at 220 kV/cm was observed for the BSBT-KBT20 ceramics from the electric-field polarization behavior.