Concerning the practical applications, dielectric capacitors with simultaneously high recoverable energy density (W rec ) and large energy storage efficiency (η) under a low electric field is imperative and challenging. Herein, a strategy of complex ions substitution is proposed to achieve the goal. The (1- x )(0.75Na 0.5 Bi 0.5 TiO 3 -0.25SrTiO 3 )- x La(Mg 2/3 Ta 1/3 )O 3 (NBST- x LMT) ceramics were fabricated through a solid-state reaction method. A significantly enhanced breakdown electric field (E b ) of 246.03 kV/cm is obtained in NBST-0.06LMT ceramics due to the refined average grain size (AGS), the enhanced band gap width and the inhibited oxygen vacancies by LMT doping. Furthermore, a high W rec of 3.18 J/cm 3 and large η of 86% are concurrently achieved in NBST-0.06LMT ceramics under a relatively low electric field of 246 kV/cm. Meanwhile, the variations of (W rec , η) under 170 kV/cm are less than 10% from 30 ℃ to 200 ℃, indicating an excellent thermal stability. Besides, the ceramics show a fast discharge rate of 155 ns by a charge-discharge measuring. In general, our results demonstrate the strategy of complex ions substitution is an effective way to achieve high energy storage performance under a relatively low electric field in NBT-based ceramics. • Complex ions (La3+, Mg2+ and Ta5+) substitution was proposed to achieve high energy storage performance. • An enhanced Eb (246.03 kV/cm) was realized in NBST ceramics. • A high Wrec of 3.18 J/cm3and large η of 86% were concurrently obtained under 246 kV/cm. • The (Wrec, η ) exhibits excellent thermal stability from 30 ℃ to 200 ℃.