A dramatic reduction in the sintering temperature of the refractory sodium β′′-alumina solid electrolyte via cold sintering

The cold sintering process is successfully applied to one of the most refractory solid-state sodium-ion electrolytes, namely sodium beta alumina (SBA). By using a hydroxide-based transient solvent, SBA is densified below 400 °C, whereas conventional solid-state sintering is known to require sintering temperatures around 1600 °C. This dramatic reduction in sintering temperature (ca. Tsinter∼ 20% of Tm) is achieved by cold sintering with the addition of 10 wt% solid NaOH transient phase, 360 MPa of uniaxial pressure, and heating to 350-375 °C, for a dwell time of three hours. The resulting pellets exceed 90% of the theoretical density for SBA and exhibit ionic conductivities of ∼10^(−2) S cm^(−1) at 300 °C, as measured by electrochemical impedance spectroscopy. The structural changes occurring during cold sintering are reversed with an intermediate temperature annealing step (ca. 1000 °C) which improves the ionic conductivity. This study therefore highlights the opportunities and remaining challenges in applying cold sintering to refractory, air-sensitive, electroceramics.

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Work Title A dramatic reduction in the sintering temperature of the refractory sodium β′′-alumina solid electrolyte via cold sintering
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Open Access
Creators
  1. Zane Grady
  2. Arnaud Ndayishimiye
  3. Clive Randall
Keyword
  1. Cold sintering
  2. Solid electrolyte
  3. Beta alumina
License In Copyright (Rights Reserved)
Work Type Article
Publisher
  1. Journal of Materials Chemistry A
Publication Date September 16, 2021
Publisher Identifier (DOI)
  1. https://doi.org/10.1039/d1ta05933e
Deposited August 02, 2022

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  • Added Grady-J-MatsChemA-July_2022.pdf
  • Added Creator Zane Grady
  • Added Creator Arnaud Ndayishimiye
  • Added Creator Clive Randall
  • Published
  • Updated Work Title, Keyword, Description, and 1 more Show Changes
    Work Title
    • A dramatic reduction in the sintering temperature of the refractory sodium β′′-alumina solid electrolyteviacold sintering
    • A dramatic reduction in the sintering temperature of the refractory sodium β′′-alumina solid electrolyte via cold sintering
    Keyword
    • Cold sintering, Solid electrolyte, Beta alumina
    Description
    • <p>The cold sintering process is successfully applied to one of the most refractory solid-state sodium-ion electrolytes, namely sodium beta alumina (SBA). By using a hydroxide-based transient solvent, SBA is densified below 400 °C, whereas conventional solid-state sintering is known to require sintering temperatures around 1600 °C. This dramatic reduction in sintering temperature (ca. T<sub>sinter</sub>∼ 20% ofT<sub>m</sub>) is achieved by cold sintering with the addition of 10 wt% solid NaOH transient phase, 360 MPa of uniaxial pressure, and heating to 350-375 °C, for a dwell time of three hours. The resulting pellets exceed 90% of the theoretical density for SBA and exhibit ionic conductivities of ∼10<sup>−2</sup>S cm<sup>−1</sup>at 300 °C, as measured by electrochemical impedance spectroscopy. The structural changes occurring during cold sintering are reversed with an intermediate temperature annealing step (ca.1000 °C) which improves the ionic conductivity. This study therefore highlights the opportunities and remaining challenges in applying cold sintering to refractory, air-sensitive, electroceramics.</p>
    • <p>The cold sintering process is successfully applied to one of the most refractory solid-state sodium-ion electrolytes, namely sodium beta alumina (SBA). By using a hydroxide-based transient solvent, SBA is densified below 400 °C, whereas conventional solid-state sintering is known to require sintering temperatures around 1600 °C. This dramatic reduction in sintering temperature (ca. T<sub>sinter</sub>∼ 20% of T<sub>m</sub>) is achieved by cold sintering with the addition of 10 wt% solid NaOH transient phase, 360 MPa of uniaxial pressure, and heating to 350-375 °C, for a dwell time of three hours. The resulting pellets exceed 90% of the theoretical density for SBA and exhibit ionic conductivities of ∼10&(−2) S cm^(−1) at 300 °C, as measured by electrochemical impedance spectroscopy. The structural changes occurring during cold sintering are reversed with an intermediate temperature annealing step (ca. 1000 °C) which improves the ionic conductivity. This study therefore highlights the opportunities and remaining challenges in applying cold sintering to refractory, air-sensitive, electroceramics.</p>
    Publication Date
    • 2021-10-14
    • 2021-09-16
  • Updated Description Show Changes
    Description
    • <p>The cold sintering process is successfully applied to one of the most refractory solid-state sodium-ion electrolytes, namely sodium beta alumina (SBA). By using a hydroxide-based transient solvent, SBA is densified below 400 °C, whereas conventional solid-state sintering is known to require sintering temperatures around 1600 °C. This dramatic reduction in sintering temperature (ca. T<sub>sinter</sub>∼ 20% of T<sub>m</sub>) is achieved by cold sintering with the addition of 10 wt% solid NaOH transient phase, 360 MPa of uniaxial pressure, and heating to 350-375 °C, for a dwell time of three hours. The resulting pellets exceed 90% of the theoretical density for SBA and exhibit ionic conductivities of ∼10&(−2) S cm^(−1) at 300 °C, as measured by electrochemical impedance spectroscopy. The structural changes occurring during cold sintering are reversed with an intermediate temperature annealing step (ca. 1000 °C) which improves the ionic conductivity. This study therefore highlights the opportunities and remaining challenges in applying cold sintering to refractory, air-sensitive, electroceramics.</p>
    • <p>The cold sintering process is successfully applied to one of the most refractory solid-state sodium-ion electrolytes, namely sodium beta alumina (SBA). By using a hydroxide-based transient solvent, SBA is densified below 400 °C, whereas conventional solid-state sintering is known to require sintering temperatures around 1600 °C. This dramatic reduction in sintering temperature (ca. T<sub>sinter</sub>∼ 20% of T<sub>m</sub>) is achieved by cold sintering with the addition of 10 wt% solid NaOH transient phase, 360 MPa of uniaxial pressure, and heating to 350-375 °C, for a dwell time of three hours. The resulting pellets exceed 90% of the theoretical density for SBA and exhibit ionic conductivities of ∼10^(−2) S cm^(−1) at 300 °C, as measured by electrochemical impedance spectroscopy. The structural changes occurring during cold sintering are reversed with an intermediate temperature annealing step (ca. 1000 °C) which improves the ionic conductivity. This study therefore highlights the opportunities and remaining challenges in applying cold sintering to refractory, air-sensitive, electroceramics.</p>
  • Updated