Lead-free (1 − x)(0.94Na 0.5 Bi 0.5 TiO 3 -0.06BaTiO 3 )-x(Sr 0.85 Bi 0.1 )-(Mg 1/3 Nb 2/3 )O 3 ((1 − x)(NBT-BT)-xSBMN) ceramics are synthesized using the traditional solid-state reaction method. The introduction of SBMN leads to a dense microstructure with small mean grain size. The temperature-dependent dielectric spectrum reveals that the sample with x = 0.24 shows the best temperature stability with T S occurring around room temperature. A large recoverable energy storage density value of 3.05 J/cm 3 , high efficiency of 89%, and excellent temperature (25− 140 °C)/frequency (1−100 Hz) stabilities are simultaneously achieved in the ceramic. The variation of recoverable energy storage density is less than 7% in the temperature range of 25−140 °C. The ceramic also has a high power density of 67.86 MW/cm 3 .