Ultrahigh power density and energy storage density of Ti-free Ca-doped (Pb,La) (Zr,Sn)TaO₃ antiferroelectric ceramics

Antiferroelectric ceramics have attracted much attention for application in pulsed power systems due to their high discharge energy density and energy storage density. There is no easily reduced Ti⁴⁺ in (Pb,La) (Zr,Sn)O₃-based antiferroelectric, which is beneficial for the preparation of low-cost ceramic capacitors by co-sintering with base metals as dielectric materials in a reducing atmosphere. However, in (Pb,La) (Zr,Sn)O₃-based antiferroelectric ceramics, it is difficult to achieve more than 90% energy storage efficiency due to the existence of secondary phase transition. Here, the oxygen vacancy is compensated by Ta⁵⁺ to increase the domain flipping, and the relaxation degree is increased by Ca²⁺ to improve the energy storage efficiency. The energy storage efficiency, energy storage density and discharge energy density are effectively improved by co-doping Pb_0.98−xLa_0.02Ca_x(Zr_0.6Sn_0.4)_0.97Ta_0.02O₃ (x = 0, 0.005, 0.01, and 0.015) with Ta⁵⁺ and Ca²⁺. The energy storage efficiency of all components is above 90%. Among them, Pb_0.97La_0.02Ca_0.01(Zr_0.6Sn_0.4)_0.97Ta_0.02O₃ exhibited a high recoverable energy density (W_rec = 7.93 J cm⁻³) and an excellent energy storage efficiency (η = 93.9%) at 300 kV cm⁻¹. In addition, the ceramic exhibited a high discharge energy density (W_dis = 6.28 J cm⁻³), a high power density (P_D = 276.9 MW cm⁻³), and a fast discharge rate (t_0.9 = 287 ns) at a relatively low electric field of 290 kV cm⁻¹. The above results indicate that Pb_0.97La_0.02Ca_0.01(Zr_0.6Sn_0.4)_0.97Ta_0.02O₃ is a potential candidate material for pulse capacitors.