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Revealing the solid‐state processing mechanisms of antiferroelectric AgNbO 3 for energy storage
Author(s) -
Zhang MaoHua,
Carstensen Leif,
Zhao Changhao,
Fulanović Lovro,
Donner Wolfgang,
Koruza Jurij
Publication year - 2022
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.18091
Subject(s) - materials science , oxidizing agent , oxide , ball mill , oxygen storage , stoichiometry , oxygen , reducing atmosphere , solid solution , perovskite (structure) , thermal decomposition , analytical chemistry (journal) , chemical engineering , mineralogy , crystallography , chemistry , metallurgy , chromatography , organic chemistry , engineering
AgNbO 3 is one of the prominent lead‐free antiferroelectric (AFE) oxides, which readily exhibits a field‐induced AFE to ferroelectric phase transition and thus a high energy storage density. The solid‐state synthesis of AgNbO 3 is considered difficult and an oxidizing atmosphere is typically employed during AgNbO 3 processing, on the premise that oxygen can prevent possible decomposition of the silver oxide at high temperatures. However, details about the influence of processing parameters on the functional properties of AFE AgNbO 3 are insufficiently understood. In this work, the solid‐state reaction of a stoichiometric AgO and Nb 2 O 5 mixture was investigated. We found that ball milling can convert AgO into metallic Ag, which is beneficial for lowering the reaction temperature for the formation of the perovskite phase to 500‒600℃. Moreover, the influence of the processing atmosphere (air, O 2 , and N 2 ) was investigated by thermal analysis and in situ X‐ray diffraction. Since the reaction between Ag and Nb 2 O 5 to form AgNbO 3 requires oxygen uptake, AgNbO 3 was only found to form in air and O 2 , whereby the kinetics were faster in the latter case. All the sintered AgNbO 3 samples exhibited a similar crystallographic structure, although the samples processed in O 2 had a lower oxygen vacancy concentration. Despite this, well‐defined AFE double polarization loops were obtained in all cases. Our results indicate that decomposition of sliver oxide during ball milling is beneficial for the solid‐state reaction, while a pure O 2 atmosphere is not essential for the synthesis of high‐quality AgNbO 3 . These findings may simplify the processing and facilitate further research of AgNbO 3 ‐based antiferroelectrics.