The microstructures and electrical properties of a series of (1-x)Ba0.06Na0.47- Bi0.47TiO3-xLn(1/3)NbO(3)(Ln = La, Nd and Sm) ceramics prepared by the conventional solid-state reaction method were investigated. The XRD analysis revealed that all the investigated ceramics have a pure perovskite structure. A maximum energy storage density up to 1.239 J/cm(3) at 100 kV/cm was exhibited for 0.98Ba(0.06)Na(0.47)Bi(0.47)TiO(3)- 0.02Sm(1/3)NbO(3) ceramics. The activation energies of carrier migration and relaxation process in the ceramics showed nearly similar values of similar to 1.0eV. The diffusion factor gamma corresponding to Ln = La, Nd and Sm at a frequency of 100 kHz were estimated to be 1.96, 1.89 and 1.91, respectively. Detailed studies on dielectric spectroscopy revealed a relaxor behavior with diffuse phase transition in these ceramic systems. The general approach to equivalent circuit model of BNBT-xLnN ceramics has been used to interpret spectra obtained from impedance measurements. By additional use of the complex electric modulus formalism to analyze the same impedance data, the dispersion behavior and temperature-dependent relaxation processes of the ceramics may be probed. (C) 2016 Elsevier B.V. All rights reserved.