Designing lead-free antiferroelectrics for energy storage

Abstract

Dielectric capacitors, although presenting faster charging/discharging rates and better stability compared with supercapacitors or batteries, are limited in applications due to their low energy density. Antiferroelectric (AFE) compounds, however, show great promise due to their atypical polarization-versus-electric field curves. Here we report our first-principles-based theoretical predictions that Bi1−xRxFeO3 systems (R being a lanthanide, Nd in this work) can potentially allow high energy densities (100–150 J cm−3) and efficiencies (80–88%) for electric fields that may be within the range of feasibility upon experimental advances (2–3 MV cm−1). In addition, a simple model is derived to describe the energy density and efficiency of a general AFE material, providing a framework to assess the effect on the storage properties of variations in doping, electric field magnitude and direction, epitaxial strain, temperature and so on, which can facilitate future search of AFE materials for energy storage.

Giant energy density and high efficiency achieved in bismuth ferrite-based film capacitors via domain engineering

“…The favorable RFE property, together with the enhanced breakdown strengths, gives rise to giant energy storage densities of ~70 J cm −3 in the BFSTO films with both x  = 0.60 and 0.75, which are superior to other reported lead-free systems and rival the best lead-based systems. This corresponds with the first-principle simulations by Xu et al 55, proving the huge potential of BFO-based materials as high-energy-density dielectrics. It may be noted that the simulations predicted even higher energy density (100–150 J cm −3 ), indicating that there is still much room for further improvement in the BFSTO system.…”

An Unconventional Transient Phase with Cycloidal Order of Polarization in Energy‐Storage Antiferroelectric PbZrO3

“…This implies that the energy is stored in a very complicated manner. Referring to the AFE orthorhombic phase, the 0.04–0.21 eV energy gap with the FE M and FE R phase indicates that about 10–57 J cm −3 is stored during the phase transition, which well agrees with the first‐principles calculated value of ≈19 J cm −3 at 900 kV cm −1 in PbZrO 3 …”

Enhanced Energy Storage with Polar Vortices in Ferroelectric Nanocomposites

“…In high-quality ferroelectric/antiferroelectric thin films the energy storage density is much higher than that of ceramics due to the enhanced dielectric breakdown strength. For example, a very high energy storage density of 154 J/cm 3 at 218MV/m was achieved in the antiferroelectric film (Bi 1/2 Na 1/2 ) 0.9118 La 0.02 Ba 0.0582 (Ti 0.97 Zr 0.03 )O 3 [2], and recently Bin Xu et al [3] predicted via first principle calculations an energy storage density of 100-150 J/cm 3 in the lead free Bi 1−x R x FeO 3 system. However, from a practical point of view, the energy density is determined by the processing method and quality of the film as failure is often driven by flaws.…”

“…The energy density of commercial dielectric capacitors is usually of the order of 1-2 J/cm 3 , far inferior to electrochemical capacitors (≈ 20 J/cm 3 ) [1]. The energy density of a dielectric material is essentially given by U= EdP , where E is the electric field and P is the polarization.…”