Effects of TiO2 doping on Li+-stabilized Na-β″-alumina for energy storage applications

Dirksen, Cornelius; Skadell, Karl; Schulz, Matthias; Stelter, Michael

doi:10.1016/j.seppur.2018.12.028

Cited by 15 publications

(21 citation statements)

References 22 publications

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“…The activation energies calculated for the measured conductivity of the pure sample and sample prepared with 1 mol% of nanosized SnO 2 additive were 0.31 and 0.35 eV, respectively. The smaller grain size and higher grain-boundary volume in the sample with 1 mol% of SnO 2 can be considered as a reason for its higher activation energy [36,37]. Since the Arrhenius plots of the conductivity data tend to converge at low temperatures ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Low-temperature sintering of sodium beta alumina ceramics using nanosized SnO2 sintering aid

Ahmadi

2020

PAC

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Sodium beta alumina ceramics (Na 1.67 Al 10.67 Li 0.33 O 17) is used in sodium sulphur batteries as solid electrolyte. In the present work, sodium beta alumina powder has been synthesized by the solid state method using Al 2 O 3 , Na 2 CO 3 and Li 2 CO 3 as the starting materials. The effect of nanosized SnO 2 additive on sintering behaviour, microstructure, mechanical and electrical properties of sodium beta alumina ceramics has been investigated. The results indicated that the addition of 1 mol% of nanosized SnO 2 particles, determined as the optimal amount, can decrease the sintering temperature of sodium beta alumina ceramics for about 100°C, and lead to the excellent densification and proper microstructure, as well. Improvement in sintering behaviour of beta alumina ceramics in the presence of nanosized SnO 2 additive is apparently due to the formation of a liquid phase during the sintering process and lower sodium loss. The results also proved that by SnO 2 addition, ionic conductivity at 300°C, fracture strength and Weibull modulus of the sintered samples are improved by 66%, 58%, and 45%, respectively. These improvements could be attributed to the higher amount of β ′′-Al 2 O 3 phase, higher density and more uniform microstructure.

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Section: Resultsmentioning

confidence: 99%

Low-temperature sintering of sodium beta alumina ceramics using nanosized SnO2 sintering aid

Ahmadi

2020

PAC

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“…The slurry was produced by ball milling (400 rpm; 20 min; 30 g of 3 mm-ZrO 2 -milling balls) of 9.5 g Na-β-alumina [ 6 ], 0.5 g TiO 2 (Alfa Aesar, Haverhill, MA, USA 99.7%), 1 g Y-stabilized ZrO 2 (Tosoh Corporation, Tokyo, Japan), 14.75 mL deionized water and 0.45 g organic binder. The calcined xerogel discs were spin coated (POLOS Spin150i, Putten, The Netherlands) according to the spinning regime in Table S1 .…”

Section: Methodsmentioning

confidence: 99%

“…Lab-scale syntheses of Na-β-alumina powder are established for several methods: Solidstate reaction [11,12], infiltration method [13], and citrate complexation (also called sol-gel synthesis) [14][15][16][17]. Dense Na-β-alumina electrolytes are obtained after fractionation, uniaxial pressing, and sintering [1,6,12,[16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

“…The ionic conductivity of both crystal structures is caused by a conduction layer, where the mobile Na-ions are located on the c axis, and can, hence, move along this direction. [ 4 , 5 ] Thereby, an ionic conductivity of >0.2 S∙cm −1 at 300 °C can be reached [ 3 , 6 ]. Other recent studies undermine the general research interest in sodium-ion batteries [ 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

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Sodium Solid Electrolytes: NaxAlOy Bilayer-System Based on Macroporous Bulk Material and Dense Thin-Film

et al. 2021

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A new preparation concept of a partially porous solid-state bilayer electrolyte (BE) for high-temperature sodium-ion batteries has been developed. The porous layer provides mechanical strength and is infiltrated with liquid and highly conductive NaAlCl4 salt, while the dense layer prevents short circuits. Both layers consist, at least partially, of Na-β-alumina. The BEs are synthesized by a three-step procedure, including a sol-gel synthesis, the preparation of porous, calcined bulk material, and spin coating to deposit a dense layer. A detailed study is carried out to investigate the effect of polyethylene oxide (PEO) concentration on pore size and crystallization of the bulk material. The microstructure and crystallographic composition are verified for all steps via mercury intrusion, X-ray diffraction, and scanning electron microscopy. The porous bulk material exhibits an unprecedented open porosity for a NaxAlOy bilayer-system of ≤57% with a pore size of ≈200–300 nm and pore volume of ≤0.3 cm3∙g−1. It contains high shares of crystalline α-Al2O3 and Na-β-alumina. The BEs are characterized by impedance spectroscopy, which proved an increase of ionic conductivity with increasing porosity and increasing Na-β-alumina phase content in the bulk material. Ion conductivity of up to 0.10 S∙cm−1 at 300 °C is achieved.

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“…Na-β″-alumina is typically doped with Mg 2+ or Li + to prevent decomposition of Na-β″-alumina at the commonly applied sintering temperatures of about 1600 °C [ 8 , 13 , 14 ]. Typical compositions for stabilized Na-β″-alumina electrolytes are Na 1.67 Mg 0.67 Al 10.33 O 17 or Na 1.67 Li 0.33 Al 10.67 O 17 [ 13 , 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Influence of 3d Transition Metal Doping on Lithium Stabilized Na-β″-Alumina Solid Electrolytes

et al. 2021

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Na-β″-alumina is the commercially most successful solid electrolyte due to its application in ZEBRA and NAS® batteries. In this work, Li-stabilized Na-β″-alumina electrolytes were doped with 3d transition metal oxides, namely TiO2, Mn3O4, and NiO, in order to improve their ionic conductivity and fracture strength. Due to XRD and EDX measurements, it was concluded that Mn- and Ni-ions are incorporated into the crystal lattice of Na-β″-alumina. In contrast, TiO2 doping results in the formation of secondary phases that enable liquid-assisted sintering at temperatures as low as 1500 °C. All dopants increased the characteristic fracture strength of the electrolytes; 1.5 wt% of NiO doping proved to be most efficient and led to a maximal characteristic fracture strength of 296 MPa. Regarding the ionic conductivity, TiO2 doping showed the uppermost value of up to 0.30 S cm−1 at 300 °C. In contrast to the other dopants, TiO2 doping lowered the sintering temperature needed to obtain a dense, stable, and highly conductive Na-β″-alumina electrolyte suitable for applications in Na based batteries.

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Effects of TiO2 doping on Li+-stabilized Na-β″-alumina for energy storage applications

Cited by 15 publications

References 22 publications

Low-temperature sintering of sodium beta alumina ceramics using nanosized SnO2 sintering aid

Low-temperature sintering of sodium beta alumina ceramics using nanosized SnO2 sintering aid

Sodium Solid Electrolytes: NaxAlOy Bilayer-System Based on Macroporous Bulk Material and Dense Thin-Film

Influence of 3d Transition Metal Doping on Lithium Stabilized Na-β″-Alumina Solid Electrolytes

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