Superior energy-storage performance in BaTiO₃-AgNbO₃ binary relaxor via the competitions of multiple polar orders

In the field of dielectric energy storage, ferroelectric ceramics commonly have low electric storage efficiency due to high remanent polarization. Thus, they are usually transformed into relaxors for enhancing electric storage efficiency. In most cases, the transformation not only reduces remanent polarization but also reduces the maximum polarization. To solve the dilemma, we propose a multiple polar orders competing strategy. Experimentally the strategy is achieved in a novel BaTiO₃-AgNbO₃ solid solution. BaTiO₃ is a classic ferroelectric with a long-range polar order while AgNbO₃ is antiferroelectric with multiple antiparallel polar orders. Due to the competitions of multiple polar orders in BaTiO₃-AgNbO₃, during the transformation from ferroelectric to relaxor, the remanent polarization is reduced significantly while the maximum polarization is maintained in the binary solid solution. As a result, a high recoverable energy density (W_rec) of 6.04 J/cm³ with an efficiency (η) of 86.8 % is achieved in the optimized composition of 0.92BaTiO₃–0.08AgNbO₃. Encouragingly, excellent temperature/frequency/fatigue stability and outstanding discharge capability demonstrate its potential for practical applications. The present research offers a novel binary solid solution for pulse power devices, and emphasizes the polarization competitions strategy as a new reference for optimizing the energy storage performance of relaxor ferroelectrics.