Electrical properties and scaling studies of Na3+x ZrxSc2−x(PO4)3 glass ceramic electrolyte for use in Na-ion batteries (original) (raw)
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Asian Journal of Chemistry/Asian journal of chemistry, 2024
In the present investigation, a glass-ceramics with the composition of xNa2S + (100-x)P2S5, where x = 40, 45, 50 and 55, were successfully synthesized by employing the melt-quenching method. Comprehensive characterization of the glass-ceramic samples was conducted using X-ray diffraction (XRD), UV-visible spectroscopy, impedance spectroscopy (IS) and field emission scanning electron microscopy (FE-SEM) techniques. The XRD analysis revealed the presence of three distinct phases, namely NaPO3, Na2S2O3 and Na3PS4, in all samples. Significantly, NaPO3 and Na2S2O3 exhibited an orthorhombic crystal structure, while Na3PS4 displayed a tetragonal crystal structure. The densities of the synthesized samples fell within the range of 2.24 to 2.35 g/cc, surpassing those of Li2S-based solid electrolytes commonly used in portable devices. The band gap of the materials varied from 2.99 to 3.60 eV. Significantly, an inverse relationship between Na2S content (modifier) and band gap was observed, indicating a decrease in band gaps with increasing Na2S content. This phenomenon is beneficial for enhancing ionic conductivity. At ambient temperature, samples with x values of 50 and 55 demonstrated remarkable conductivity on the order of 10-4 S cm-1. Overall, the synthesized glass ceramics exhibit promising features, such as higher density compared to conventional Li2S-based solid electrolytes and favourable band gap values, suggesting their potential application in enhancing ionic conductivity for various electronic devices.
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.
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...
Structure and Conductivity Correlation in NASICON Based Na3Al2P3O12 Glass: Effect of Na2SO4
Frontiers in Materials
Identifying the factors influencing the movement of sodium cations (Na+) in glasses accelerates the possible options of glass-based solid electrolyte materials for their applications as a promising electrolyte material in sodium-ion batteries. Nevertheless, due to the poor correlation between the structure and conductivity in glass materials, identifying the factors governing the conductivity still exists as a challenging task. Herein, we have investigated the DC-conductivity variations by correlating the structure and conductivity in sodium superionic conductor (NASICON) based Na3Al2P3O12 (NAP) glass (mol%: 37.5 P2O5—25.0 Al2O3—37.5 Na2O) due to the successive substitution of Na2SO4 for Al2O3. Structural variations have been identified using the Raman and magic-angle spinning nuclear magnetic resonance (MAS-NMR) (for 31P, 23Na, and 27Al nuclei) and conductivity measurements have been done using the impedance spectroscopy. From the ac-conductivity spectra, the correlations between m...
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.
Development of sodium ion conducting mixed anion glassy solid-state electrolytes
The short-range order (SRO) structures of glasses in the Na4P2S 7-xOx, 0 ≤ x ≤ 7, series were investigated on samples prepared by planetary ball milling (PBM). Like other glasses prepared by PBM, the glassy nature of the prepared materials was confirmed by x-ray diffraction (XRD) showing that they were structurally amorphous and by differential scanning calorimetry (DSC) showing that each composition exhibited a reproducible glass transition temperature (Tg). The short-range order (SRO) structure of these glasses were determined using Raman, Fourier Transform Infrared (FT-IR), and 31 P Magic Angle Spinning NMR (MAS NMR) spectroscopies to investigate how oxygen and sulfur are bonded in the various SRO structural units that were found in these glasses. The three spectroscopic techniques gave further evidence that the resulting glasses were completely reacted from their polycrystalline starting materials Na2S, P2S5 and P2O5. It was found that significant disproportionation reactions occur in these compositions in which the original as batched and expected pyro-phosphate SRO units, P 1 = 2 Na/P, for x = 0 undergo a transformation to form ortho-phosphate (P 0 , 3 Na/P) and meta-phosphate (P 2 , 1 Na/P) SRO structures with increasing x such that there is a conservation of Na + charge, on average 2Na/P. In this nomenclature, the superscript describes the number of bridging sulfurs (BSs) and the number of Na per P plus one (arising from the P +5 valency) describing the number of non-bridging sulfurs (NBSs) on each of the SRO units. As seen in earlier work on other mixed oxy-sulfide (MOS) glass forming systems, the stronger Lewis base O = , compared to S = , is found to preferentially form bridging oxygen (BOs) in the form of P 2 SRO units by bonding to the stronger Lewis acid P +5 , compared to Na +. This leaves the weaker Lewis base S = to bond to the weaker Lewis acid, Na + in the form of non-bridging sulfurs (NBSs) on the charge compensation required P 0 groups. Using both charge balance and quantitative 31 P MAS NMR measurements, a complete composition map of all of the SRO structures present in these glasses has been created.
Improved ionic conductivity of lithium-zinc-tellurite glass-ceramic electrolytes
Results in Physics
An enhancement in the secondary battery safety demands the optimum synthesis of glass-ceramics electrolytes with modified ionic conductivity. To achieve improved ionic conductivity and safer operation of the battery, we synthesized Li 2 O included zinc-tellurite glass-ceramics based electrolytes of chemical composition (85-x)TeO 2 ÁxLi 2 OÁ15ZnO, where x = 0, 5, 10, 15 mol%. Samples were prepared using the melt quenching method at 800°C followed by thermal annealing at 320°C for 3 h and characterized. The effects of varying temperature, alternating current (AC) frequency and Li 2 O concentration on the structure and ionic conductivity of such glass-ceramics were determined. The SEM images of the annealed glass-ceramic electrolytes displayed rough surface with a uniform distribution of nucleated crystal flakes with sizes less than 1 lm. X-ray diffraction analysis confirmed the well crystalline nature of achieved electrolytes. Incorporation of Li 2 O in the electrolytes was found to generate some new crystalline phases including hexagonal Li 6 (TeO 6), monoclinic Zn 2 Te 3 O 8 and monoclinic Li 2 Te 2 O 5. The estimated crystallite size of the electrolyte was ranged from %40 to 80 nm. AC impedance measurement revealed that the variation in the temperatures, Li 2 O contents, and high AC frequencies have a significant influence on the ionic conductivity of the electrolytes. Furthermore, electrolyte doped with 15 mol% of Li 2 O exhibited the optimum performance with an ionic conductivity %2.4 Â 10 À7 S cm À1 at the frequency of 54 Hz and in the temperature range of 323-473 K. This enhancement in the conductivity was attributed to the sizable alteration in the ions vibration and ruptures of covalent bonds in the electrolytes network structures.
NASICON-like Na3Zr2(SiO4)2PO4 (NZSP) ceramic solid electrolyte with high ionic conductivity, safety and durability becomes the main focus and attention as an alternative for traditional liquid electrolytes. NZSP containing NH4H2PO4 and Na3PO4⋅12H2O as the phosphate source have been extensively studied as a solid electrolyte, but a deep understanding of the relationship between crystal growth and ionic conductivity is still lacking. Herein, we synthesized NZSP via solid-state reaction using NaH2PO4 as the phosphate source. The impact of different sintering holding time on the crystal phase, microstructure, ionic conductivity and relaxation time of NZSP solid electrolytes were investigated. Microstructure studies revealed that the faceted NZSP sintered at 1100°C for 24 h has the lowest formation ZrO2, highest densification with the least pores. In addition, the sample achieved the highest room temperature ionic conductivity (4.11 ⋅ 10− 4 S cm-1) and the shortest relaxation time (0.4 µ...