Enhancement of Energy Storage Density and Efficiency of PbHfO3 Doped with La Antiferroelectric Thin Films

Antiferroelectric materials are widely used in industry owing to their outstanding energy storage properties, excellent fatigue resistance, and satisfactory stability. In this study, Pb1–3x/2LaxHfO3 (abbreviated as PLH-x) antiferroelectric nanofilms were fabricated using the sol–gel method, and their microstructure, antiferroelectric, and energy storage properties were investigated. The PLH-x films exhibited an orthogonal perovskite structure and good crystallinity. La doping altered the long-range ordering of the film’s lattice structure, generating higher breakdown field strengths and finer hysteresis lines. The PLH-0.01 film showed the best energy storage performance with a recoverable energy density (Wrec) of 26.74 J/cm3 and an energy storage efficiency (η) of 68.35%. After 108 test cycles, Wrec and η decreased by only 3.6 and 2.3%, respectively, demonstrating the outstanding fatigue resistance and stability of the PLH-0.01 film. Moreover, the PLH-0.01 film exhibited good temperature stability and excellent frequency stability. Thus, the energy storage and fatigue characteristics of PLH-x films were considerably improved through La doping. These remarkable improvements confirm the potential of using the PLH-x films for preparing dielectric capacitors.