The synthesis of 25 Li2O – 10 GeO2 – 60 SiO2 – 5 R (R = TeO2, SrO, SeO2, Tl2O, Al2O3) glasses was done by melt quenching technique. X-ray diffraction (XRD) studies confirmed the crystalline phases of synthesized samples after the heat treatment, which is also portrayed in Scanning Electron Microscope (SEM) images. Energy Dispersive Spectroscopy (EDS) depicted the presence of the elements used in the synthesis. Differential Scanning Calorimetry (DSC) curves evidenced ceramic nature of all samples, also their glass-forming ability and thermal stability, which are high for Al-doped sample. X-ray Photoelectron Spectroscopy (XPS) studies revealed the relative increment of BOs in the network of the Al-doped sample. Makishima–Mackenzie model was employed to calculate Young's modulus, bulk modulus, shear modulus, longitudinal modulus, Poisson's ratio, microhardness, fractal bond connectivity, average crosslink density, and bond number per unit volume of the samples. These findings indicated the notable mechanical properties of the Al2O3 mixed sample, owing to its large dissociation energy and high field strength. The optical band gap, index of refraction, molar polarizability, molar refractivity, metallization criterion, optical transmission, reflection loss, optical basicity, and electronic polarizability were calculated using the optical absorption studies. Fourier-Transform Infrared Spectroscopy (FTIR) studies of the synthesized samples revealed the presence of SiO4, LiO4, TeO3, TeO4, GeO4, AlO4, and AlO6 structural units in the glass ceramic matrix. From the impedance analysis, it was observed that the ionic conductivity of the glass ceramics containing 5 mol% of Al2O3, Tl2O is minimal (2.06 × 10?6 and 0.44 × 10?6 S/cm at 200 °C respectively) at all temperatures, indicating their suitability for dielectric applications. The maximum ionic conductivity (8.21 × 10?6 S/cm at 200 °C) of the TeO2 doped sample appraises its suitability for solid electrolytic applications

25Li2O-(10-x)GeO2-60SiO2-5Al2O3-xTiO2 (x = 1–5 mol%) samples namely T1-T5 were produced through the melt quenching method. X-ray Diffraction (XRD) studies recognized the amorphous and crystalline phases of samples. Among T1 to T5 samples, the T3 sample exhibited high glass-forming ability and thermal stability (?T = 173 °C), with high crystallization energy (273.89 kJ/mol) and low Avrami index. Mixed electronic-ionic conduction of samples was studied by employing the Small Polaron Hopping (SPH) model. DC ionic conduction of samples was studied by utilizing the Anderson and Stuart model. A novel approach was used to find strain energy in samples using shear moduli from the Makishima-Mackenzie model. The T3 sample had the lowest ionic conductivity (3.86 ×10?9 S/cm at 303 K), highest activation energy (0.808 eV), and exhibited a low (0.50 ×10?15 cm2 V?1 s?1 at 303 K) charge carrier mobility. These findings indicate that the optimized T3 sample is suitable for dielectric applications.

Sodium-ion batteries (SIBs) are game-changing in large-scale energy storage technology compared to lithium-ion batteries (LIBs) due to abundant reserves, safety, and cost-effectiveness. However, serious issues in Mn-based P2-type cathodes, such as phase transitions, the Jahn–Teller effect, and Mn dissolution, hinder the success of SIBs. Herein, we report that altering the manganese oxide precursors in the solid-state synthesis of P2-type Na0.65Ni0.25Mn0.75O2 (NNMO) leads to structural variations and improvements in electrochemical properties. X-ray diffraction with refined data confirms that all samples are in the P2-type phase, with changes in lattice parameters and cell volume. Raman spectroscopy and electron spin resonance verify the presence of oxygen defects in the P2-type NNMO materials. Furthermore, X-ray photoelectron spectroscopy analysis of the Mn2O3 precursor-used Na0.65Ni0.25Mn0.75O2 (NNMO-2) sample reveals slightly higher Mn4+ and lower Mn3+ mixed valence states compared to other samples. The potential profile and dQ/dV plot of NNMO-2 exhibit solid-solution behavior, delivering an initial discharge capacity of 151 mAh/g and 152 mAh/g at 0.1 C. The sample demonstrates excellent capacity retention of 85.34% and 77.28% after 100 cycles at a 1 C rate, with a Coulombic efficiency exceeding 98% in both tested voltage ranges (1.5–4.0 V and 2.0–4.3 V), attributed to Mn charge compensation. Moreover, the Na-ion diffusion coefficient, estimated to be around 10–10 cm2/s using the galvanostatic intermittent titration technique and the reduced charge transfer resistance, confirmed by impedance measurements, further highlight the electrochemical benefits of the NNMO-2 sample. Overall, the results suggest that the Mn2O3 precursor can be a suitable raw material for solid-state reactions synthesizing P2-type Na0.65Ni0.25Mn0.75O2 cathode materials for sodium-ion battery applications

The present study demonstrates structural, elastic, thermal and electronic properties of transition metal M (M: Fe, Co and Ni) doped copper nitride (Cu3N) using pseudopotential based density functional calculations as implemented in Quantum ESPRESSO simulation code. The exchange-correlation is approximated by PBE-GGA functional. The doped matrices represented as Cu3NM are verified to be stable structures, both thermodynamically and mechanically. Tailoring of elastic properties and their anisotropy due to M doping has been successfully demonstrated through comprehensive analysis of the computed elastic stiffness coefficients, elastic moduli, elastic anisotropy factors and spatial variation of the elastic moduli, which were not explored yet. An increase in bulk modulus due to M doping ensures enhanced mechanical stability under isotropic stress. Conversely, while doping of Co and Ni enhances the shear resistance of the host material, Fe doping slightly reduces it. Superior ductile nature of all the studied systems predicts their suitability for application in flexible electronics. It is evident that doping of M substantially reduces the elastic anisotropy of Cu3N. Using the calculated elastic moduli, velocity of acoustic waves and its anisotropy for Cu3N and Cu3NM are also predicted. The anisotropy in the acoustic velocity of the studied materials recommends their potential application in acoustic devices with directional selectivity. It is also noticed that, while average acoustic velocity is reduced due to Fe doping, it increases for Co and Ni doping. Furthermore, analysis of computed Debye temperature and minimum thermal conductivity forecasts their employability as thermal barrier coatings. Finally, the calculations reveal ferromagnetic nature of Cu3NFe and Cu3NCo with respective induced magnetic moments of 2.71 and 1.47 ?B/cell, recommending their potential application in spintronics. It is also proved that, the M-d ? Cu-d coupling stabilizes the ferromagnetic ordering in such magnetic systems. On the other hand, Cu3NNi is observed to be non-magnetic

Fluoride-ion batteries (FIBs) offer better theoretical energy densities and temperature stability, making them suitable alternatives to expensive Li-ion batteries. Major studies on FIBs operating at room temperature focus mainly on MSnF4 (M: Ba and Pb) solid electrolytes due to their favourable ionic conductivity values. PbSnF4 is the best fluoride ionic conductor known to date. However, it exhibits poor electrochemical stability. The present work demonstrates the development of TlSn2F5 through a single-step mechanical milling method. TlSn2F5 exhibits a better ionic conductivity value compared to the earlier reported various solid electrolytes, such as BaSnF4, KSn2F5, and La0.9Ba0.1F2.9, commonly considered for FIBs. Ionic transport number measurement using the dc polarization method indicates that TlSn2F5 is an ionic conductor. Furthermore, 19F NMR spectra measured at various temperatures demonstrate that the rise in conductivity with temperature is attributed to the rapid transport of fluoride ions. The present study indicates that TlSn2F5 can be utilized as a potential solid electrolyte for fabricating FIBs. © 2024 The Royal Society of Chemistry.

The escalating need for lithium-ion batteries (LIBs), driven by their expanding range of applications in our daily lives, has led to a surge in interest in metal selenides as potential anode materials. Among them, Bi2Se3 stands out as a promising anode material for LIBs due to its unique layered structure. Herein, we explored hexagonally structured layered Bi2Se3 platelets synthesized using the solvothermal method. The electrochemical performance of these platelets in LIBs was thoroughly examined, revealing an impressive initial discharge specific capacity of 556 mA h g?1 at a current density of 100 mA g?1 and a coulombic efficiency of 66.5%. Improved cycling stability, rate performance, and discharge voltage profile at various current densities were observed. The plateaus observed during the charge/discharge profile were clearly illustrated by the CV results. The reaction kinetics indicated that both ion diffusion and pseudo-capacitance behavior are crucial for the observed high electrochemical performance. Moreover, the hexagonal Bi2Se3 platelets exhibited a high ion-diffusion coefficient of 1.8 × 10?13 cm2 s?1 and a charge transfer impedance of 23 ? post-cycling. Furthermore, the crystal structure, lattice vibrational bonding, and surface morphology of Bi2Se3 were explored using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. FTIR spectroscopy was utilized for identifying the functional groups, while X-ray photoelectron spectroscopy (XPS) was used to identify the elemental composition and oxidation states of Bi2Se3

Research studies on biomass-derived hard carbon are gaining notable scientific interest due to its potential application as a sustainable anode for Li-ion batteries (LIBs). The current study presents the development of hard carbon from soap-nut seed biomass, with the optimization of its pyrolysis temperature, followed by chemical activation using KOH- and ZnCl2-activated reagents. The physicochemical behaviour of the developed materials is studied by utilizing XRD, HRTEM, BET, and XPS techniques. CV and galvanostatic charge–discharge curves are examined to assess the potential of the material for the application as a sustainable anode in LIBs. The electrochemical performance of the developed materials obtained at various pyrolysis temperatures (600, 700, 800 and 900 °C) and chemically activated with KOH and ZnCl2 is explained with respect to their interplanar spacing, ID/IG ratio, and specific pore area. Among the different pyrolysis temperatures, the hard carbon pyrolyzed at 700 °C exhibits the maximum reversible specific discharge capacity of 391 mA h g?1 at a current density of 100 mA g?1. The present study also demonstrates that the electrochemical performance of the hard carbon deteriorates after chemical activation with ZnCl2, whereas chemical activation with KOH enhances its performance. The chemically-activated hard carbon using KOH exhibits a reversible specific discharge capacity of 454 mA h g?1 at 100 mA g?1 and delivers a better cycling stability (500 cycles) of 83 mA h g?1 at 300 mA g?1

The development of all-solid-state Li-ion batteries (ASSLIBs) has gained significant attention due to their potential for improved safety, energy density, and performance compared to traditional Li-ion batteries. NASICON-type Li-ion conducting solid electrolytes (LICSEs) have emerged as a promising candidate for use in ASSLIBs because of their high Li-ion conductivity and excellent chemical stability. Replacement of the liquid electrolytes from conventional batteries with suitable solid electrolytes not only resolves some of their serious safety challenges, such as leakages and thermal instabilities, but also enhances their cycle life and power densities. One of the critical challenges in realizing all-solid-state batteries is not only the development of thermally and electrochemically stable solid electrolytes exhibiting good ionic conductivities but also reducing the impedance associated with the electrolyte-electrode interfaces in the device. NASICON-type solid electrolytes exhibit better stabilities compared to garnet-based systems, and they also exhibit better conductivity values in comparison to perovskite-based materials. This chapter shows the recent advances and challenges of NASICON-type LICSEs, LiM2(PO4)3 (M: Zr, Ti, and Ge), and their applications in all-solid-state batteries. Various strategies known to achieve solid electrolytes with improved ionic conductivity values by doping with dopants of different oxidation states—and further, the correlation of their transport results with respect to their crystal structure—are reviewed. The use of LiM2(PO4)3-based solid electrolytes in various polymer matrices for the advancement of composite-polymer electrolytes is underlined. Various synthesis methods known for the development of LiM2(PO4)3-based polycrystalline materials and composite-polymer electrolytes are summarized. We also provide an outlook for future research and development of NASICON-type LICSEs for use in ASSLIBs. Overall, this chapter highlights the potential of NASICON-type LICSEs as a key component for the development of high-performance ASSLIBs.

Investigations on SnF-based solid electrolytes are gaining significant scientific attention because of their promising applications as solid electrolytes for all-solid-state fluoride ion batteries (FIBs) operating at room temperature. FIBs are potential alternatives for expensive Li-ion batteries with toxic and flammable liquid electrolytes. SrSnF belongs to the MSnF (M: Pb, Ba, and Sr)-type materials exhibiting a layered structure. Here, we present the structural and transport characteristics of two polymorphs of SrSnF using X-ray diffraction and impedance spectroscopy techniques. SrSnF crystallizing in a cubic fluorite structure is obtained just by mechanical milling the powder samples of SrF and SnF taken in a 1:1 ratio for 10 h, whereas annealing the milled powder at 623 K in the N atmosphere transforms SrSnF from its cubic phase to the stable tetragonal structure. The structural details of both the cubic and tetragonal SrSnF have been obtained by performing the Rietveld refinement. The resultant phase change after soft annealing enhances the room-temperature conductivity value from 2.05 × 10 S/cm for the cubic phase to 1.16 × 10 S/cm for the tetragonal phase. The transport number measurement by the dc polarization technique with the cell of configuration Ag/SrSnF/Ag reveals that the conductivity is due to the ions. The frequency response of conductivity data is analyzed using the Almond-West formalism to find their hopping frequency and mobile carrier concentration factor at different temperatures. The scaling of the frequency-dependent conductivity spectra shows that the relaxation behavior of the mobile ions is temperature independent.

Li-ion conducting solid electrolytes exhibiting NASICON structure have received promising research interest for their potential applications in safer all-solid-state Li-ion batteries. LiZr 2 (PO 4 ) 3 (LZP) belongs to the NASICON-type of materials exhibiting Li-ion conduction and furthermore offers lower interfacial resistance and good electrochemical stability against the Li-metal. LZP is known to crystallize in four polymorphs, namely monoclinic, orthorhombic, triclinic, and rhombohedral, and further, LZP crystallizing in rhombohedral structure is known to exhibit the highest ionic conductivity. The present work demonstrates the synthesis of LZP exhibiting rhombohedral structure at room temperature using the modified sol-gel method at a lower sintering temperature (900 °C). The effect of sintering temperature on the structural and transport behavior of LZP is studied by XRD, SEM, and impedance spectroscopy techniques. The complex impedance plots show the presence of two depressed semicircles associated with different capacitance values, indicating both bulk and grain boundary conductions. The bulk, grain boundary and total conductivity of LZP sintered at different temperatures are calculated. The bulk conductivity of LZP is found to increase with increase in the sintering temperature from 800 °C to 1100 °C, whereas LZP sintered at 900 °C exhibits the highest total conductivity value at room temperature, indicating the significant role of the grain boundary conductions in the total conductivity of LZP material. The transport results of LZP sintered at different temperatures are discussed with their unit cell volume (XRD), relative density (Archimedes method), and microstructure (SEM). Furthermore, the ionic transport number measurement by dc polarization shows that the major charge carriers are the ions and the electrochemical stability measurements by both cyclic voltammetry and linear sweep voltammetry show its stability with Li-metal is up to 5.1 V.

The present work shows the comparative studies on the magnetic properties of Ni 0.4 Zn 0.6-x Co x Fe 2 O 4, (Ni–Zn–Co) and Ni 0.4 Zn 0.6-x Mn x Fe 2 O 4 (Ni–Zn–Mn) with x  = 0.00 to 0.25 in steps of 0.05, ferrites synthesized by sol-gel autocombustion and conventional ceramic methods. Rietveld refinement data confirms the formation of single phase - spinel crystal structure in all the samples. The role of ferromagnetic dopants like Co and Mn on the structural, microstructural, magnetic characteristics such as Curie temperature (T c ), saturation magnetization and coercivity of NiZnFe 2 O 4 ferrite are investigated. The influences of crystallite size obtained by using two different synthesis methods on different magnetic properties are highlighted. Continuous T c increases have been noticed in both instances along with increasing dopant concentrations. However, compared to Ni–Zn–Mn ferrites, Ni–Zn–Co ferrites display greater T c values. The experimental observed magnetic moments measured from vibrating sample magnetometer (VSM) are fitted with the theoretical data. The saturation magnetization values exhibit a marginal increase in the bulk form of the material as compared to its nanocrystalline counterparts. On the basis of distribution of cation and exchange interactions between magnetic cations at its tetrahedral and octahedral sublattices, the typical mechanisms accountable for the observed trends were elucidated. In addition, the dc -resistivity and dielectric loss are measured to show the application aspects of the materials in various potential device applications.

The search for obtaining a Co free low-cost and high-capacity anode thin film material for high energy density all-solid thin film batteries has been driving the increasing innovation and research in Li-ion battery (LIB) technology. In the present case, LiFe 5 O 8 (LFO) thin films are prepared by pulsed laser deposition (PLD) technique and their electrochemical properties, Li ion dynamics, conducting processes at various frequencies and current rates are explored. LFO thin films are seen to crystallize in ordered ? -phase with an inverse spinel structure. Chemical state of all the elements is analysed using X-ray photoelectron spectroscopy method. Cyclic voltammeter (CV) study carried out between 0–3 V shows the reduction peak at 0.76 V initially and in the later cycles at 0.86 V with a small shift depicting the exact conversion type behaviour of the LFO thin film. LFO thin film exhibits specific discharge capacity of 25 ?Ah/cm 2 at 10 ?A/cm 2 current density during the first cycle. Rate capability measurements are carried out at various current densities of 10, 20, 30, 40, 50 and 10 ?A/cm 2. Li-ion diffusion coefficient during the de-lithiation and lithiation process is seen to be 3.78 × 10 ?14  cm 2 /s and 1.41 × 10 ?13  cm 2 /s, respectively. CV studies at various scan rates indicates that the mechanism of Li + storage is dominated by a diffusion-controlled process at low scan rates and with increasing scan rate it becomes a surface-controlled process. Electrochemical impedance studies at various frequencies shows the decrease in charge transfer resistance with increasing cycles. Combined structural, chemical, electrochemical and impedance studies of LFO thin films indicates that these films can be employed for fabricating Co and Ni free all-solid thin film Li-ion batteries for energy storage applications.

Research studies on Na-ion batteries (NIBs) are receiving significant scientific and commercial attention recently owing to the availability of low-cost, safe, and abundant materials in comparison to the conventional Li-ion batteries. The cathode material in a battery plays a crucial role in determining its cell capacity and cycle life. NASICON-based NaV(PO), NVP, is known to be a favorable cathode material for NIBs due to its structural stability with high Na-ion mobility. The present work shows the structural and electrochemical properties of bare NVP/C and NVP/C partially doped with low-cost and much abundant transition element Fe/Mn at the toxic and expensive V site. The bare NVP/C as well as the transition-metal ion-doped NVP/C materials are prepared by the sol-gel method. XRD and FTIR studies confirm the formation of materials exhibiting the rhombohedral NVP structure (R3¯ c) without any trace of impurities. The presence of a carbon layer in the investigated cathode materials is confirmed by the HRTEM micrographs; furthermore, the oxidation states of different transition-metal elements present are evaluated by X-ray photoelectron spectroscopy. Electrochemical studies reveal that the moderate doping of Fe/Mn in NVP/C results in an enhancement in discharge capacities in the doped materials at different C rates compared to the bare NVP/C sample. The differences in their electrochemical results are explained with respect to their Na-ion diffusion coefficient values obtained using the Randles-Sevcik equation. A Mn-doped NVP/C material exhibits an enhanced discharge capacity of 107 mA h gat 0.1C with 90% capacity retention even after 100 cycles at 1C current rate. At the end, a Na-ion full cell (NVMP/C||HC) comprising a Mn-doped NVP/C cathode with the commercial hard carbon anode delivering a discharge capacity of 90 mA h gis demonstrated.

Recent reports on fluoride ion batteries (FIBs) show its promising credentials as suitable alternatives for Li-ion batteries suffering with issues like high cost, limited source, and safety. Unlike to the other alternative battery technologies such as Na, FIBs are in the early stage of progress. Development of solid electrolytes with fast fluoride ion transport is one of the major challenges in FIBs. NH 4 Sn 2 F 5 belongs to the SnF 2 based MSn 2 F 5 (M: K, Rb, and NH 4 ) solid electrolytes exhibiting two-dimensional F ion conduction. The present work reports the structural and transport details of mechanochemically synthesized NH 4 Sn 2 F 5, where the material is prepared just by milling the initial SnF 2 and NH 4 F powders (2:1) for 10 h without any heat treatment. The formation of the material exhibiting monoclinic structure at room temperature (RT) is confirmed by X-ray diffraction followed by the Rietveld refinement. The temperature dependent conductivity results at different temperature regions are explained with respect to its structural transformations, which is furthermore correlated with the differential scanning calorimetry observation. Later the conductivity values at different temperatures of mechanochemically prepared NH 4 Sn 2 F 5 are compared with the earlier reported MSn 2 F 5 (M: Na and K) materials synthesized by the same method and the results are explained with respective to their crystal structure. The current study shows that the presence of the larger NH 4 cation in MSn 2 F 5 (M: Na, K, NH 4 ) systems causes fast transport of F ions resulting in the highest fluoride ionic (anionic) conductivity value. Like BaSnF 4, the solid electrolyte which is often used by many research groups for different FIBs operating at RT, mechanochemically synthesized NH 4 Sn 2 F 5 has a great potential to be tested as a solid electrolyte in both conversion type and intercalation type FIBs because of its higher RT conductivity value arising from the motion of F ions.

A novel memory capacitor structure has been presented with AlO/AlO bilayer dielectrics on high mobility Epitaxial-GaAs substrate. We have demonstrated the chemical and electrical properties of metal–electrode/AlO/AlO/epi-GaAs-based memory device in detail. Sputter-grown non-stoichiometric AlO has been used for both the charge trapping layer and blocking layer due to its intrinsic charge trapping capability and high bandgap. Ultra-thin tunneling layer of thicknesses 5 nm and 15 nm were prepared by atomic layer deposition technique and memory properties were compared on promising high mobility Epitaxial-GaAs/Ge heterostructure. The proposed device shows excellent charge trapping properties with a maximum memory window of 3.2 V at sweep voltage of ± 5 V, with good endurance and data retention properties. Oxygen-deficient AlO layer acted as a charge trapping layer without any additional blocking layer which is impressive for non-volatile memory application on high mobility epi-GaAs substrate. In addition, density Functional Theory (DFT) has been employed to understand the physical origin of the intrinsic charge trapping defects in AlO dielectric layer.

Na 3 Zr 2 Si 2 PO 12 based solid electrolytes are well known materials because of their potential applications in different solid-state ionic devices. This review article presents the structural and transport results of Na 3 Zr 2 Si 2 PO 12 based solid electrolytes prepared by different dry and wet methods known in the literature. The advantages and limitations of different synthesis methodologies to achieve the phase pure, high dense Na 3 Zr 2 Si 2 PO 12 based materials are presented. The influence of the valence state, ionic radii of aliovalent dopants on the ionic conductivity of Na 3 Zr 2 Si 2 PO 12 have been discussed with respect to their crystal structure. The role of sintering temperature, sintering durations, and sintering agents on the phase purity, density, and conductivity of Na 3 Zr 2 Si 2 PO 12 based solid electrolytes are reviewed. Besides Na 3 Zr 2 Si 2 PO 12 based polycrystalline solid electrolytes, the transport results of Na 3 Zr 2 Si 2 PO 12 based grain boundary free glasses and flexible polymer electrolytes are also discussed. The applications of Na 3 Zr 2 Si 2 PO 12 based solid electrolytes in different electrochemical devices are outlined.

LaF 3 based fast ion conducting materials are well-known potential solid electrolytes for applications in different solid-state ionic devices like fluoride ion batteries. LaF 3 of crystallite size in the nanometer range is obtained by mechanical milling the as procured LaF 3 for a few hours. The mechanically milled LaF 3 shows higher conductivity in comparison to its un-milled forms. The enhanced conductivity value exhibited by the mechanically milled LaF 3 is explained with respect to its smaller crystallite size and induced micro-strain during the milling process. The influence of bivalent dopant, BaF 2 (fluorite structure) on LaF 3 (tysonite structure) has been studied using XRD and impedance spectroscopy techniques. La 0.9 Ba 0.1 F 2.9 shows higher conductivity in comparison to LaF 3 conductivity and the observed result is explained with respect to the differences in the ionic radii and valence state of the dopant Ba 2+ and the host La 3+ ions. Furthermore, the role of the co-dopant CaF 2 on the structural and transport properties of BaF 2 doped LaF 3 keeping same La and F stoichiometry as in La 0.9 Ba 0.1 F 2.9 is investigated. The transport results indicate a lower conductivity value in La 0.9 Ba 0.05 Ca 0.05 F 2.9 in comparison to La 0.9 Ba 0.1 F 2.9 conductivity.

Na 3 Zr 2 Si 2 PO 12 is a well-known solid electrolyte because of its potential applications in Na-ion batteries and gas sensors. In this work, the structural and transport properties of Na 3 Zr 2 Si 2 PO 12 synthesized by solid-state reaction and sol–gel techniques are compared. In both methods, a monoclinic phase for Na 3 Zr 2 Si 2 PO 12 is confirmed by X-ray Diffraction and FTIR spectroscopy techniques. The impedance measurements show higher conductivity in Na 3 Zr 2 Si 2 PO 12 prepared by solid-state reaction. The role of sintering temperatures on the transport results of Na 3 Zr 2 Si 2 PO 12 has been investigated. The temperature dependent conductivity plots of Na 3 Zr 2 Si 2 PO 12 show a change in the slope at 163 °C corresponding to its structural phase transition from monoclinic to rhombohedral form, which is further supported by its DSC result. Furthermore, the role of excess Na on the ionic conductivity of Na 3 Zr 2 Si 2 PO 12 using two different Na precursors Na 2 CO 3 and Na 3 PO 4 keeping same Na-stoichiometry has been investigated.