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.