Constructing novel SrTiO3-based composite ceramics with high energy storage performance under moderate electric field

With the awakening of human environmental awareness, the research of lead-free dielectric ceramics is imperative. In this paper, an innovative tactic is proposed to improve the comprehensive energy storage properties of SrTiO3-based ceramics by constructing diphase compounds. The bismuth layer-structured BaBi2Nb2O9 ferroelectric is introduced into the perovskite-structured Sr0.6(Na0.5Bi0.5)0.4TiO3 ceramic through a traditional solid-state method. The breakdown strength is significantly enhanced with the increase of BaBi2Nb2O9, accompanied by the strengthened relaxor behavior. Ultimately, optimal (1-x)Sr0.6(Na0.5Bi0.5)0.4TiO3-xBaBi2Nb2O9 ceramics with x = 0.09 possess outstanding energy storage performance, involving high recoverable energy storage density of Wrec ∼ 3.6 J/cm3 under moderate electric field, excellent conversion efficiency of η ∼ 94.3 %, superior stability of temperature (20∼120 °C) and frequency (1∼100 Hz). In addition, rapid discharge rate of t0.9∼60.6 ns and high power density of 59.45 MW/cm3 at 160 kV/cm are also accomplished. This work certifies the possibility of establishing composite ceramics to design high energy storage materials. •Energy storage performance is optimized in SrTiO3-based ceramics.•A perovskite-Aurivillius diphase composite is constructed.•Breakdown strength is enhanced by BaBi2Nb2O9.•Wrec ∼3.6 J/cm3 and η ∼94.3 % are achieved under moderate electric field.