Tuning the growth of faceted Na3Zr2(SiO4)2PO4 NASICON-type solid electrolyte and its effect on microstructure-conductivity relationship (original) (raw)
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Ceramics International
In this work, the effect of varying the size of the precursor raw materials SiO 2 and ZrO 2 in the solid-state synthesis of NASICON in the form Na 3 Zr 2 Si 2 PO 12 was studied. Nanoscale and macro-scale precursor materials were selected for comparison purposes, and a range of sintering times were examined (10, 24 and 40 h) at a temperature of 1230°C. Na 3 Zr 2 Si 2 PO 12 pellets produced from nanopowder precursors were found to produce substantially higher ionic conductivities, with improved morphology and higher density than those produced from larger micron-scaled precursors. The nanoparticle precursors were shown to give a maximum ionic conductivity of 1.16 9 10-3 S cm-1 when sintered at 1230°C for 40 h, in the higher range of published solid-state Na 3 Zr 2 Si 2 PO 12 conductivities. The macro-precursors gave lower ionic conductivity of 0.62 9 10-3 S cm-1 under the same processing conditions. Most current authors do not quote or consider the precursor particle size for solid-state synthesis of Na 3 Zr 2 Si 2 PO 12. This study shows the importance of precursor powder particle size in the microstructure and performance of Na 3 Zr 2 Si 2 PO 12 during solid-state synthesis and offers a route to improved predictability and consistency of the manufacturing process.
Designing High Ionic Conducting NASICON-type Na3Zr2Si2PO12 Solid-Electrolytes for Na-Ion Batteries
The Journal of Physical Chemistry C, 2020
The present work investigates the synthesis and characteristics of Na Super-Ionic Conductor (NASICON)-type Sc 3+-and Yb 3+-doped Na3Zr2Si2PO12 solid electrolyte for application in solid-state Na-ion batteries. A significant improvement of Na-ion conductivity in Na3Zr2Si2PO12 has been achieved through crystal engineering and microstructure refinement. The presence of monoclinic-ZrO2 impurity phase adversely affecting the Na-ion conductivity is eliminated by using cubic-ZrO2 precursor at the place of monoclinic-ZrO2 in conventional solid-state reaction method. Utilizing cubic-ZrO2 also refined the microstructure with thin and microcracks free grain boundaries. A replacement of 16.5 at.% of Zr 4+ by Sc 3+ in Na3Zr2Si2PO12 enhances the room-temperature total ionic conductivity from 0.61 mS.cm-1 to 0.96 mS.cm-1. Replacing 11.11 at.% of Sc 3+ by Yb 3+ further improves the room-temperature ionic conductivity to 1.62 mS.cm-1 which is >2.5 times higher than that of bare Na3Zr2Si2PO12. The strategic approach used to raise the ionic conductivity in the current work can be applied to other materials, paving a way towards realizing high-performance solidelectrolytes for viable and economic Na-ion batteries. A room-temperature conductivity of 1.51 mS.cm-1 for Sc 3+ /Yb 3+-doped Na3Zr2Si2PO12 measured employing Na-metal as electrodes confirms Na-ion conduction. Furthermore, a very low current density (~10-7 A/cm 2) in the cyclic-voltammetry profile of Na│solid-electrolyte│Na cell demonstrates the suitability of Sc 3+ /Yb 3+-doped Na3Zr2Si2PO12 as a solid-electrolyte for Na-ion batteries. A detailed analysis of these materials has been performed, and the possible reasons for the conductivity enhancement are discussed.
Journal of Materials Science, 2019
In this work, the effect of varying the size of the precursor raw materials SiO2 and ZrO2 in the solid-state synthesis of NASICON in the form Na3Zr2Si2PO12 was studied. Nanoscale and macro-scale precursor materials were selected for comparison purposes, and a range of sintering times were examined (10, 24 and 40 h) at a temperature of 1230 °C. Na3Zr2Si2PO12 pellets produced from nanopowder precursors were found to produce substantially higher ionic conductivities, with improved morphology and higher density than those produced from larger micron-scaled precursors. The nanoparticle precursors were shown to give a maximum ionic conductivity of 1.16 × 10−3 S cm−1 when sintered at 1230 °C for 40 h, in the higher range of published solid-state Na3Zr2Si2PO12 conductivities. The macro-precursors gave lower ionic conductivity of 0.62 × 10−3 S cm−1 under the same processing conditions. Most current authors do not quote or consider the precursor particle size for solid-state synthesis of Na3Z...
Solid State Communications, 2007
A novel inorganic solid electrolyte with a layered framework structure stable up to 1043 K, Na 14.5 [Al(PO 4 ) 2 F 2 ] 2.5 [Ti(PO 4 ) 2 F 2 ] 0.5 (NATP), has been hydrothermally prepared and characterized by single-crystal and powder X-ray diffraction techniques, X-ray fluorescence (XRF) analysis, IR spectroscopic measurement, thermogravimetric and differential thermal analysis (TGA and DTA). NATP crystallizes in the acentric hexagonal space group P3 with a = 10.448(2), b = 10.448(2), c = 6.589(3)Å, Z = 1, containing a large number of Na + cations in the interlamellar space and the cavities of its framework. There are six different crystallographic Na + cationic sites, in which 8% Na(5) and 12% Na(6) sites are vacant. Electrical conductivity measurements show that Na + cations exhibit a high mobility with two domains for the electrical conductivity versus temperature.
Applied Physics A
Na-ion conducting Na 3+x [Zr x Sc 2−x (PO 4) 3 ] (x = 0, 0.25, 0.5 and 0.75 mol%) glass samples with NASICON-type phase were synthesized by melt quenching method and glass-ceramics were formed by heat treating the precursor glasses at their crystallization temperatures. The major and minor crystalline phases such as [Na 3 Sc 2 (PO 4) 3 (ICSD-27740) (NASICON), ZrP 2 O 7 (ICSD-15084), ZrO 2 (ICSD-66781) and Zr 2 O(PO 4) 2 (ICSD-1922)] are precipitated in all the glass-ceramic samples. The best bulk conductivity has been observed for Na 3.5 Zr 0.5 Sc 1.5 (PO 4) 3 glass-ceramic sample (σ b = 1.92 × 10 −4 S/cm) which exhibits lowest activation energy of 0.492 eV. The single master curve in the scaling analysis revealed that this glass samples show evidence of temperature-independent conduction transport mechanism.
Solid State Ionics, 1997
The NASICON-type Na1.5Nb0.3Zr1.5(PO4)3 was prepared by solid state reaction of Nb2O5 and the precursor γ-NaHZr(PO4)2 at 700 °C. The EPR spectra showed a signal with a g factor of 1.984 assigned to Nb (IV) species in octahedral oxygen environments. The X-ray powder diffraction pattern obtained with monochromatic radiation was indexed on the basis of a rhombohedral cell, the hexagonal parameters being aH = 8.8061(2) and . The Na+ ion conduction was measured by the complex impedance method (frequency range: 0.1–105 Hz; temperature range: 20–500 °C) on four pellets previously sintered at 450, 750, 900 and 1000 °C. The conductivity data are discussed in relation to the sintering temperature. An activation energy of 0.60 eV for the movement of Na+ ions in the NASICON framework has been found.
Ionic and Thermal Transport in Na-Ion-Conducting Ceramic Electrolytes
International Journal of Thermophysics
We have studied the ionic and thermal transport properties along with the thermodynamic key properties of a Na-ion-conducting phosphate ceramic. The system Na1+xAlxTi2−x(PO4)3 (NATP) with x = 0.3 was taken as a NASICON-structured model system which is a candidate material for solid electrolytes in post-Li energy storage. The commercially available powder (NEI Coorp., USA) was consolidated using cold isostatic pressing before sintering. In order to compare NATP with the “classical” NASICON system, Na1+xZr2(SiO4)x(PO4)3−x (NaZSiP) was synthesized with compositions of x = 1.7 and x = 2, respectively, and characterized with regard to their ionic and thermal transport behavior. While ionic conductivity of the NaZSiP compositions was about more than two orders of magnitude higher than in NATP, the thermal conductivity of the NASICON compound showed an opposite behavior. The room temperature value was about a factor two higher in NATP compared to NaZSiP. While the thermal conductivity decr...
LiSnZr(PO4)3: NASICON-type solid electrolyte with excellent room temperature Li+ conductivity
Journal of Alloys and Compounds, 2018
Development of solid electrolytes with good lithium ion conductivity is one of the key prerequisites of high performing rechargeable all-solid-state lithium batteries. In this work, NA-Super-Ionic-CONductor (NASICON)-type LiSnZr(PO 4) 3 ceramics fabricated via a sol-gel route were characterized using Synchrotron x-ray diffraction, Raman Spectroscopy, x-ray photoelectron spectroscopy (XPS) and complex impedance spectroscopy. Stabilization of high Li + conducting rhombohedral (R3 c) phase at room temperature was confirmed by the Rietveld refinement of synchrotron x-ray diffraction data. LiSnZr(PO 4) 3 sample sintered at 1000 °C exhibited an excellent room temperature bulk and total conductivity ~ 0.1 mScm-1 and 1.45×10-5 Scm-1 with associated activation energies of ~ 0.36 eV and ~ 0.38 eV, respectively. Direct current polarization study confirmed the conductivity of LiSnZr(PO 4) 3 as predominantly ionic in nature. The role of inductive effect in improving the room temperature ionic conductivity by utilizing the electronegativity of counter-cations in NASICON framework is also discussed.
Ionics
In this article, highly Na + ion conducting glass samples based on Na 3+x [Cr x Ti 2-x (PO 4) 3 ] (x = 0, 0.25, 0.5, and 0.75 mol%) (NCTP x) system was prepared via melt quenching technique. The as-formed precursor glasses were transformed into glassceramics by heat treating at and above T c for different time schedules. Powder XRD indicates the formation of NASICON type phase (Na 3 Ti 2 (PO 4) 3) which is known for its higher stability and ionic conductivity. This phase is precipitated due to the partial replacement of tetrahedral Ti 4+ ions by trivalent Cr 3+ ions in the NCTP glass-ceramic network. The NCTP 0.5 glass-ceramic sample heat treated at 1066 K for 9 h exhibited best bulk conductivity (σ = 8.52 × 10 −4 S/cm) and minimum activation energy (0.448 eV). For T c > 1066 K, impure phases such as Cr 2 O 3 and NaCrP 2 O 7 were precipitated along the grain boundaries which resist the migration of Na + ions between the grains. The best conducting NCTP 0.5 sample after crystallization (glass-ceramic) exhibited good chemical stability in ambient atmosphere for 60 days.
Novel halloysite based nanoionic Na2ZnSiO4 solid electrolyte: Structural and electrical properties
Ceramics International, 2020
Halloysite clay was acid-treated to obtain SiO 2 nanoparticles that were used as one of the starting reagents to synthesise clay-based Na 2 ZnSiO 4 (Clay-NZS) through sol-gel method. XRD and FESEM results showed that the Clay-NZS produced a nanocrystalline structure, with grain sizes of 50-70 nm, in comparison to its synthetic counterpart (Synth-NZS) that had grain sizes of~200 nm. BET measurements showed that Clay-NZS pellets pressed and sintered at the same condition as Synth-NZS were denser, allowing for a better grain-grain contact. Conductivity studies using EIS demonstrated superior conductivity of Clay-NZS in contrast to Synth-NZS due to the exponential reduction in grain boundary resistance, with calculated conductivity values of = × − − σ S c m 2.95 10 Clay (500) 5 , testifying that nanostructured ionic materials (nanoionics) provided easier diffusion pathway for ionic conduction in Clay-NZS.