TY - JOUR
T1 - Reactive Templated Grain Growth and Thermoelectric Power Factor Enhancement of Textured CuFeO2 Ceramics
AU - Tato, Masahiko
AU - Shimonishi, Rina
AU - Hagiwara, Manabu
AU - Fujihara, Shinobu
N1 - Funding Information:
This work was partially supported by a Grant-in-Aid for Young Scientists (No. 18K13996) from the Japan Society for the Promotion of Science (JSPS). The authors would like to thank TOYO Corporation for assistance in the Hall coefficient measurement.
Publisher Copyright:
Copyright © 2020 American Chemical Society.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/2/24
Y1 - 2020/2/24
N2 - The delafossite-type CuFeO2 (CFO) is a promising p-type thermoelectric oxide reported to show a large Seebeck coefficient, but the lack of a texturing method for CFO ceramics limits their thermoelectric performance. Here, we show that textured CFO ceramics with an enhanced thermoelectric power factor can be obtained by a facile process based on the reactive templated grain growth (RTGG) method. Nanorods of α-FeOOH were synthesized by a hydrothermal reaction and used as templates for the RTGG process. Textured CFO ceramics with a high c-axis orientation were obtained by ordinal uniaxial pressing of a mixed powder of the α-FeOOH nanorods and Cu2O particles and subsequent reaction sintering process. The best CFO ceramic with the highest orientation degree (Lotgering factor) of 0.71 was obtained at a sintering temperature of 1020 °C. It was found that textured CFO ceramics were formed through a topotactic conversion process via an intermediate α-Fe2O3 phase. The textured CFO ceramic showed a high in-plane electrical conductivity, leading to an enhanced thermoelectric power factor of 1.4 × 10-4 W m-1 K-2 at 700 K, which is the highest value ever reported for undoped CFO ceramics.
AB - The delafossite-type CuFeO2 (CFO) is a promising p-type thermoelectric oxide reported to show a large Seebeck coefficient, but the lack of a texturing method for CFO ceramics limits their thermoelectric performance. Here, we show that textured CFO ceramics with an enhanced thermoelectric power factor can be obtained by a facile process based on the reactive templated grain growth (RTGG) method. Nanorods of α-FeOOH were synthesized by a hydrothermal reaction and used as templates for the RTGG process. Textured CFO ceramics with a high c-axis orientation were obtained by ordinal uniaxial pressing of a mixed powder of the α-FeOOH nanorods and Cu2O particles and subsequent reaction sintering process. The best CFO ceramic with the highest orientation degree (Lotgering factor) of 0.71 was obtained at a sintering temperature of 1020 °C. It was found that textured CFO ceramics were formed through a topotactic conversion process via an intermediate α-Fe2O3 phase. The textured CFO ceramic showed a high in-plane electrical conductivity, leading to an enhanced thermoelectric power factor of 1.4 × 10-4 W m-1 K-2 at 700 K, which is the highest value ever reported for undoped CFO ceramics.
KW - FeOOH nanorods
KW - delafossite-type CuFeO
KW - oxide thermoelectrics
KW - power factor
KW - reactive templated grain growth
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U2 - 10.1021/acsaem.9b02407
DO - 10.1021/acsaem.9b02407
M3 - Article
AN - SCOPUS:85081026303
VL - 3
SP - 1979
EP - 1987
JO - ACS Applied Energy Materials
JF - ACS Applied Energy Materials
SN - 2574-0962
IS - 2
ER -