Excellent energy storage properties and superior stability achieved in lead-free ceramics via a spatial sandwich structure design strategy

Abstract

Lead-free ceramics play a vital role in the context of sustainable development for energy storage applications due to their high power density, excellent high temperature resistance and nontoxicity. Nevertheless, the low energy density and small energy conversion efficiency of lead-free ceramics caused by the contradictory relation of polarization and electric breakdown strength restrict the urgent need for electronic components towards miniaturization and achieving light weight. Herein, to overcome this challenge and optimize the energy storage properties of lead-free ceramics, unlike the traditional approaches of oxide doping, adopting new sintering techniques and optimizing the composition, samples with a spatial sandwich structure were constructed and prepared by the tape casting technique. Obviously, the opposite relationship between the polarization and the electric breakdown strength can be resolved very well via this design strategy. The recoverable energy storage density reaches 6.3 J cm⁻³ together with high energy conversion efficiency (93.61%) and high applied electric field (540 kV cm⁻¹). An ultrahigh power density of 215 MW cm⁻³ and a fast discharge time of 140 ns can also be realized. In addition, the energy conversion efficiency is higher than 90% and the variation of recoverable energy storage density is less than ±2% within 1–100 Hz and 1–10⁵ fatigue cycles. Meanwhile, the change of recoverable energy storage density is also less than ±6.5% from 30 °C to 160 °C. The above results indicate that the current study helps to promote the development of eco-friendly ceramics for high energy storage applications.