Explicating the irreversible electric-field-assisted ferroelectric phase transition in the otherwise antiferroelectric sodium niobate for energy storage systems. Issue 29 (8th July 2022)

• Record Type: Journal Article
• Authors: Kim, Kwangrae; Hwang, Woohyun; Lee, Ji-Hwan; Soon, Aloysius
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 29(2022)
• Page Start: 10500
• Page End: 10510
• Publication Date: 2022-07-08
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2tc01817a
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : By means of a first-principles-based Landau–Devonshire model, we predict and explain why newly discovered intermediates can rationalize the persistent lack of a double polarization–electric field hysteresis for NaNbO3 under an applied field. Abstract : To meet the increasing demand for environment-friendly, high-performance energy devices, sodium niobate (NaNbO3 ) is considered one of the most promising lead-free antiferroelectric (AFE) oxide perovskites for green energy storage applications. However, as disclosed by recent experimental reports, under an external electric field, the room-temperature AFE P phase of NaNbO3 has been demonstrated to undergo an irreversible phase transition to the ferroelectric (FE) Q phase. This puzzle challenges our current atomic-scale understanding of this field-induced AFE-to-FE transition, and thus hinders the widespread use of NaNbO3 in lead-free AFE energy storage devices. To unravel this puzzle, we perform first-principles density-functional theory calculations to establish phase stability maps of the NaNbO3 polymorphs determined from group–subgroup relations. For the first time, we identify two new key intermediates (P′ and Q′) via the symmetry-adapted phonon mode analysis based on high-symmetry cubic phase and minimum energy pathway transition state searches, that facilitate de novo phase transition pathways for the switching of polarization with significantly lowered energy barriers. By means of a phenomenological Landau–Devonshire model, we predict and explain why these new intermediates can rationalize the persistent lack of a double polarization–electric field hysteresis for NaNbO3 under an applied field. This sets the design platform for future precise engineering of NaNbO3 at the atomic-scale for lead-free AFE energy storage applications.