Multiple electrical response and enhanced energy storage induced by unusual coexistent-phase structure in relaxor ferroelectric ceramics

The immense potential of energy storage materials applied in high energy storage devices has promoted the development of various materials and the exploration of structure. Here, we present the original observations on an unusual coexistent-phase structure in relaxor ferroelectric ceramics 0.2Pb(Mg_1/3Nb_2/3)O₃-0.8Pb(Sn_xTi_1-x)O₃ (PMN-PST). The novel structure containing independent ferroelectric and relaxor phase in a single grain induces multiple electric response. More importantly, PMN-PST ceramics with the coexistent-phase structure exhibit the enhanced energy storage based on a high voltage pulse measurement. The maximum energy density reaches up to 0.85 J/cm³ at 70 kV/cm for x = 0.48, nearly three times of that of the ferroelectric ceramic (x = 0.36). It is proposed that the coexistent-phase structure generates domain switching and gives rise to coexistent-phase charge coupling that are together responsible for the excellent energy storage performance. This work opens a new pathway to develop relaxor ferroelectric materials in high energy storage fields.