Na-β Alumina powder processing by a Na2CO3 precipitation method

Certo, J.; Furtado, C.S.; Ferreira, António Jorge; Perdigão, J. M.

doi:10.1007/bf02375790

Cited by 8 publications

(7 citation statements)

References 5 publications

(6 reference statements)

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“…Figure a shows structures of β-alumina (hexagonal, P 63/ mmc , a 0 = 0.559 nm, c 0 = 2.261 nm) and β″-alumina (rhombohedral, R 3 m , a 0 = 0.560 nm, c 0 = 3.395 nm) which contain the spinel blocks and conduction slabs. , The spinel block consists of four layers of oxygen with aluminum ions both in the octahedral and tetrahedral sites. The conduction plane consists of loosely packed oxygen and sodium ions. , β-alumina has the formula of Na 2 O·11Al 2 O 3 or NaAl 11 O 17 , whereas β″-alumina is Na 2 O·5Al 2 O 3 or NaAl 5 O 8 . Due to the stacking sequence, the unit cell of β″-alumina is 50% larger than β-alumina and, β″-alumina possesses higher Na-ion concentration in the conduction slab than those of β-alumina.…”

Section: Electrolytes For Sodium-metal Anodesmentioning

confidence: 99%

“…Ionic conductivity of polycrystalline β″-alumina depends on β″/β ratio and also depends on the grain size. A β″-alumina pellet is prepared by solid-state reaction using α-alumina and Na 2 CO 3 to obtain β″-alumina powder and then sintering the powder at high temperature over 1600 °C to reduce grain-boundary resistance. − In general, it is difficult to fabricate high-purity β″-alumina (>99%), and humidity-sensitive NaAlO 2 is formed along grain boundaries. ,, β″-Alumina is brittle, which means that it may be easily cracked, including during cell fabrication.…”

Section: Electrolytes For Sodium-metal Anodesmentioning

confidence: 99%

“…The conduction plane consists of loosely packed oxygen and sodium ions. 322,323 324 Due to the stacking sequence, the unit cell of β″alumina is 50% larger than β-alumina and, β″-alumina possesses higher Na-ion concentration in the conduction slab than those of β-alumina. Thus, β″-alumina is more conductive than β-alumina.…”

Section: Chemical Reviewsmentioning

confidence: 99%

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Sodium Metal Anodes: Emerging Solutions to Dendrite Growth

et al. 2019

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This comprehensive Review focuses on the key challenges and recent progress regarding sodium-metal anodes employed in sodium-metal batteries (SMBs). The metal anode is the essential component of emerging energy storage systems such as sodium sulfur and sodium selenium, which are discussed as example full-cell applications. We begin with a description of the differences in the chemical and physical properties of Na metal versus the oft-studied Li metal, and a corresponding discussion regarding the number of ways in which Na does not follow Li-inherited paradigms in its electrochemical behavior. We detail the major challenges for Na-metal systems that at this time limit the feasibility of SMBs. The core Na anode problems are the following interrelated degradation mechanisms: An unstable solid electrolyte interphase with most organic electrolytes, “mossy” and “lath-like” metal dendrite growth for liquid systems, poor Coulombic efficiency, and gas evolution. Even solid-state Na batteries are not immune, with metal dendrites being reported. The solutions may be subdivided into the following interrelated taxonomy: Improved electrolytes and electrolyte additives tailored for Na-metal anodes, interfacial engineering between the metal and the liquid or solid electrolyte, electrode architectures that both reduce the current density during plating–stripping and serve as effective hosts that shield the Na metal from excessive reactions, and alloy design to tune the bulk properties of the metal per se. For instance, stable plating–stripping of Na is extremely difficult with conventional carbonate solvents but has been reported with ethers and glymes. Solid-state electrolytes (SSEs) such as beta-alumina solid electrolyte (BASE), sodium superionic conductor (NASICON), and sodium thiophosphate (75Na2S·25P2S5) present highly exciting opportunities for SMBs that avoid the dangers of flammable liquids. Even SSEs are not immune to dendrites, however, which grow through the defects in the bulk pellet, but may be controlled through interfacial energy modification. We conclude with a discussion of the key research areas that we feel are the most fruitful for further pursuit. In our opinion, greatly improved understanding and control of the SEI structure is the key to cycling stability. A holistic approach involving complementary post-mortem, in situ, and operando analyses to elucidate full battery cell level structure–performance relations is advocated.

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Section: Electrolytes For Sodium-metal Anodesmentioning

confidence: 99%

Section: Electrolytes For Sodium-metal Anodesmentioning

confidence: 99%

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Sodium Metal Anodes: Emerging Solutions to Dendrite Growth

et al. 2019

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“…Fig. 3 shows the XRD patterns of the powders doped with different amounts of SiO2 that were calcined at 1200 °C for 2 h. The Na + -β phase has the theoretical fomula Na2O•11Al2O3, or NaAl11O17 [23], and the β"phase has the formula Na2O•5Al2O3, or NaAl5O8 [24]. According to Na2O-Al2O3 phase diagram proposed by Fally et al [25], the β + β"-phases coexist in a region corresponding to the formula Na2O•nAl2O3(5.33 ≤ n ≤ 8.5).…”

Section: Methodsmentioning

confidence: 99%

The Influences of Sio2 on the Sintering Behavior and the Properties of Na+- Β/Β"-Al2O3 Solid Electrolyte

Lee

Lim

2019

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SiO2-doped Na+-β/β″-Al2O3 was synthesized via a solid-state reaction, and the relationship between the SiO2 content and properties of Na+-β/β″-Al2O3 was investigated. Respective specimens were doped with 0 – 5 wt.% SiO2 as a liquid phase sintering promotor and sintered. The specimens were characterized by XRD, SEM, densimeter and impedance analyzer. In the sintered samples, the phase fraction of β″-Al2O3 decreased as the SiO2 content increased, whereas the relative sintered density was enhanced with the inclusion of less than 0.7 wt.% SiO2. The relative sintered density of Na+- β/β″-Al2O3 sintered specimen with 0.7 wt.% SiO2 doping reached 99.2 % of the theoretical density and the sintered density decreased when the amount of SiO2 was larger than 1 wt.% result from excessive liquid-phase formation during sintering. Similarly, the ionic conductivity of SiO2-doped Na+-β/β″-Al2O3 was enhanced by doping with a small amount of SiO2, whereas the addition of more than 1 wt.% SiO2 negatively affected the ionic conductivity of Na+-β/β″-Al2O3 due to a decrease in the sintered density and unfavorable phase relationship. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.14246

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“…The battery is composed of a sodium anode, a sulphur cathode, and Na + -β/β -alumina as both the electrolyte and separator [1,2]. Na + -β/β -alumina ceramics come from two parent phases designated as β-alumina and β -alumina, which have resistivities of 30 and 5 •cm, respectively, at 350 • C. The βalumina phase has the theoretical formula Na 2 O • 11Al 2 O 3 or NaAl 11 O 17 [3], and the β -alumina phase has the formula Na 2 O • 5Al 2 O 3 , or NaAl 5 O 8 [4]. According to the Na 2 O-Al 2 O 3 phase diagram proposed by Fally et al [5], the β and β phases coexist in the region corresponding to the formula Na 2 O • nAl 2 O 3 (5.33 ≤ n ≤ 8.5).…”

Section: Introductionmentioning

confidence: 99%

Effects of calcium impurity on phase relationship, ionic conductivity and microstructure of Na+- β / β″-alumina solid electrolyte

Lee

et al. 2016

Bull Mater Sci

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Ca-doped Na +-β/β-alumina was synthesized using a solid-state reaction. The changes in the properties of Na +-β/β-alumina resulting from the presence of Ca impurity were studied. Ca (0-5 wt%) was added to the respective samples, which were then sintered. The specimens were characterized using X-ray diffraction, scanning electron microscopy, densimetry and impedance analysis. In the sintered specimens, the β-alumina phase fraction decreased as Ca content increased, whereas the relative sintered density increased. The surface morphology of Cadoped Na +-β/β-alumina specimens showed a Ca-rich layer, which was the main cause of increase in the specific resistance.

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Na-β Alumina powder processing by a Na2CO3 precipitation method

Cited by 8 publications

References 5 publications

Sodium Metal Anodes: Emerging Solutions to Dendrite Growth

Sodium Metal Anodes: Emerging Solutions to Dendrite Growth

The Influences of Sio2 on the Sintering Behavior and the Properties of Na+- Β/Β"-Al2O3 Solid Electrolyte

Effects of calcium impurity on phase relationship, ionic conductivity and microstructure of Na+- β / β″-alumina solid electrolyte

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