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Ultra-high energy storage performance with mitigated polarization saturation in lead-free relaxors

Yang, Letao, Kong, Xi, Cheng, Zhenxiang, Zhang, Shujun
Journal of materials chemistry A 2019 v.7 no.14 pp. 8573-8580
ceramics, electric field, electricity generation, energy density, energy efficiency, renewable energy sources, temperature, thermal stability, tin, titanium
Relaxor ferroelectric ceramics have attracted much attention for storing the electricity generated from clean and renewable energy sources due to their high permittivity and near-zero remnant polarization. The polarization of many relaxor based ceramics tends to saturate at high electric fields, however, which limits their energy storage performance. In this study, a lead-free Sn-modified (Na₀.₅Bi₀.₅)TiO₃–SrTiO₃ system is investigated, where mitigated polarization saturation is observed with the addition of Sn⁴⁺, as a result of the different electronic configurations between d¹⁰ Sn⁴⁺ and d⁰ Ti⁴⁺. As expected, high energy density of 3.4 J cm⁻³ and energy efficiency of 90% are simultaneously achieved in (Na₀.₂₅Bi₀.₂₅Sr₀.₅)(Ti₀.₈Sn₀.₂)O₃ ceramic. In addition, the ceramic exhibits good thermal stability, with the energy storage property variations below 5% over the temperature range of −20 °C to 150 °C, and satisfactory cycling stability with a variation of less than 8% over 10⁵ cycles. All these merits demonstrate that the (Na₀.₂₅Bi₀.₂₅Sr₀.₅)(Ti₀.₈Sn₀.₂)O₃ ceramic has great potential for high power energy storage applications.