Microstructure and dielectric properties of perovskite-structured high-entropy ceramics of Pb(Zr0.25Ti0.25Sn0.25Hf0.25)O3

A dielectric high-entropy ceramic with a composition of Pb(Zr_0.25Ti_0.25Sn_0.25Hf_0.25)O₃ was designed through B-site doping, and then prepared by solid phase reaction method combined with conventional sintering in air for 3 h at 1200 ^°C, 1250 ^°C and 1300 ^°C, respectively. All the high-entropy ceramics of Pb(Zr_0.25Ti_0.25Sn_0.25Hf_0.25)O₃ possess a perovskite structure with uniform elemental distribution and their average grain size falls within the range of 3.19–5.5 μm. For the sample sintered at 1250 ^°C, the dielectric loss is less than 0.07 in the testing frequency of 1 kHz∼1 MHz in 30–350 ^°C, and the dielectric constant reaches a peak of 14356 at about 270 ^°C at 1 kHz. At room temperature, the remnant polarization P_r reaches 28.8 μC/cm². The results demonstrate that the high-entropy ceramic of Pb(Zr_0.25Ti_0.25Sn_0.25Hf_0.25)O₃ has great potentials in the dielectric and ferroelectric field.     

Liquid‐phase sintering of highly Na+ ion conducting Na3Zr2Si2PO12 ceramics using Na3BO3 additive

Na₃Zr₂Si₂PO₁₂ (NASICON) is a promising material as a solid electrolyte for all‐solid‐state sodium batteries. Nevertheless, one challenge for the application of NASICON in batteries is their high sintering temperature above 1200°C, which can lead to volatilization of light elements and undesirable side reactions with electrode materials at such high temperatures. In this study, liquid‐phase sintering of NASICON with a Na₃BO₃ (NBO) additive was performed for the first time to lower the NASICON sintering temperature. A dense NASICON‐based ceramic was successfully obtained by sintering at 900°C with 4.8 wt% NBO. This liquid‐phase sintered NASICON ceramic exhibited high total conductivity of ~1 × 10^?3 S cm^?1 at room temperature and low conduction activation energy of 28 kJ mol^?1. Since the room‐temperature conductivity is identical to that of conventional high‐temperature‐sintered NASICON, NBO was demonstrated as a good liquid‐phase sintering additive for NASICON solid electrolyte. In the NASICON with 4.8 wt% NBO ceramic, most of the NASICON grains directly bonded with each other and some submicron sodium borates segregated in particulate form without full penetration to NASICON grain boundaries. This characteristic composite microstructure contributed to the high conductivity of the liquid‐phase sintered NASICON.     

Microstructure–conductivity relationship of Na3Zr2(SiO4)2(PO4) ceramics

The ionic conductivity of solid electrolytes is dependent on synthesis and processing conditions, ie, powder properties, shaping parameters, sintering time (t_s), and sintering temperature (T_s). In this study, Na₃Zr₂(SiO₄)₂(PO₄) was sintered at 1200 and 1250°C for 0-10 hours and its microstructure and electrical performance were investigated by means of scanning electron microscopy and impedance spectroscopy. After sintering under all conditions, the sodium super-ionic conductor-type structure was formed along with ZrO₂ as a secondary phase. The microstructure investigation revealed a bimodal particle size distribution and grain growth at both T_s. The density of samples increased from 60% at 1200°C for 0 hours to 93% at 1250°C for 10 hours. The ionic conductivity of the samples increased with t_s due to densification and grain growth, ranging from 0.13 to 0.71 mS/cm, respectively. The corresponding equivalent circuit fitting for the impedance spectra revealed that grain boundary resistance is the prime factor contributing to the changing conductivity after sintering. The activation energy of the bulk conductivity (E_a,bulk) remained almost constant (0.26 eV) whereas the activation energy of the total conductivity (E_a) exhibited a decreasing trend from 0.37 to 0.30 eV for the samples with t_s = 0 and 10 hours, respectively—both sintered at 1250°C. In this study, the control of the grain boundaries improved the electrical conductivity by a factor of 6.     

Lithium ion conductivity in the solid electrolytes (Li0.25La0.25)1−xM0.5xNbO3 (M=Sr,Ba, Ca,x=0.125) with perovskite-type structure

Perovskite-type structured solid electrolytes with the general formula (Li_0.25La_0.25)_1−xM_0.5xNbO₃ (M=Sr, Ba, Ca, x=0.125) have been prepared by solid-state reaction. Their crystal structure and ionic conductivity were examined by means of X-ray diffraction analysis (XRD), scanning electron microscope (SEM), and alternating current (AC) impedance technique. All sintered compounds are isostructural with the parent compound Li_0.5La_0.5Nb₂O₆. Some impurity phase is detected at the grain boundary in the Ba- and Ca-substituted compounds. The substitution of partial Li⁺ by alkaline earth metal ions has responsibility for the cell volume expansion as determined by the XRD data. The densification is accelerated, with the overall porosity and grain boundary minimized as Sr²⁺ ions are doped. Among the investigated compounds, the perovskite (Li_0.25La_0.25)_0.875Sr_0.0625NbO₃ shows a remarkable ionic conductivity of 1.02×10⁻⁵ S/cm at room temperature (20 °C) and the lowest activation energy of 0.34 eV in comparison with 0.38 eV and 0.44 eV for the corresponding Ba- and Ca-doped samples, respectively. It is identified that the enhancement of ionic conductivity is attributed to a reduction in activation energy for ionic conduction which is related to an increase in the cell volume.     

Electrically conductive SiC ceramics processed by pressureless sintering

Polycrystalline SiC ceramics with 10 vol% Y₂O₃-AlN additives were sintered without any applied pressure at temperatures of 1900-2050°C in nitrogen. The electrical resistivity of the resulting SiC ceramics decreased from 6.5 × 10¹ to 1.9 × 10⁻² Ω·cm as the sintering temperature increased from 1900 to 2050°C. The average grain size increased from 0.68 to 2.34 μm with increase in sintering temperature. A decrease in the electrical resistivity with increasing sintering temperature was attributed to the grain-growth-induced N-doping in the SiC grains, which is supported by the enhanced carrier density. The electrical conductivity of the SiC ceramic sintered at 2050°C was ~53 Ω⁻¹·cm⁻¹ at room temperature. This ceramic achieved the highest electrical conductivity among pressureless liquid-phase sintered SiC ceramics.     

Sintering,micro-structure and Li+ conductivity of Li7−xLa3Zr2−xNbxO12/MgO (x = 0.2–0.7) Li-Garnet composite ceramics

Nb-doped Li₇La₃Zr₂O₁₂ (Nb-LLZO) is one of the promising electrolyte candidates in the Li-Garnet family due to its high Li-ion conductivity. The sintered Nb-LLZO ceramics, however, often exhibit abnormal grain growth with high porosity and poor mechanical properties. For advantaged electrochemical and mechanical properties, a uniform and dense microstructure is desired. In this research, MgO has been added as a secondary phase to inhibit abnormal grain growth in Nb-LLZO. The sintering process of the Nb-LLZO/MgO composite ceramics has been studied for different Nb doping levels (0.2–0.7 pfu) at sintering conditions of 1250?°C for 1–360?min. The ceramic density, microstructure, and Li-ion conductivity are reported. The composite ceramics have shown a very fast sintering speed. At 1250?°C, the 0.4Nb-LLZO/MgO composite can be well-sintered in 1?min. For sintering at 1250?°C for 40?min, ceramic samples showing relative density of 97%, conductivity of 6?×?10^?4 S?cm^?1 at 25?°C, and activation energy of 0.40?eV are obtained.     

Structure evolution,thermal properties and sintering resistance of promising thermal barrier coating material La2(Zr0.75Ce0.25)2O7

Rare-earth doped zirconates are promising candidate materials for high-performance thermal barrier coatings (TBCs). The phase and microstructure stability is an important issue for the materials that must be clarified, which is related to the long-term stable work of TBCs at high temperatures. In this work, La₂(Zr_0.75Ce_0.25)₂O₇ (LCZ) ceramic coatings prepared by atmospheric plasma spraying present a metastable fluorite phase, which can transform into stable pyrochlore under high-temperature annealing. The detailed structure evolution of the ceramic coatings is characterized systematically by SEM, XRD and Raman. The associated thermal properties of LCZ ceramics were also reported. Results show that LCZ ceramic has an ultralow thermal conductivity (0.65 W/m·K, 1200 °C), which is only 1/3 of that of yttria-stabilized zirconia (YSZ). The thermal expansion coefficients of LCZ ceramic increase from 9.68 × 10^-6 K^-1 to 10.7 × 10^-6 K^-1 (300 - 1500 °C), which are relatively larger than those of La₂Zr₂O₇. Besides, Long-term sintering demonstrates that LCZ ceramic coating has preferable sintering resistance at 1500 °C, which is desirable for TBC applications.     

A medium-entropy perovskite oxide La0.7Sr0.3Co0.25Fe0.25Ni0.25Mn0.25O3-δ as intermediate temperature solid oxide fuel cells cathode material

In this study, we report a novel medium-entropy perovskite oxide of La_0.7Sr_0.3Co_0.25Fe_0.25Ni_0.25Mn_0.25O_3-δ (LSCFNM73) with high constitutive entropy (S_config) as the cathode material of intermediate temperature solid oxide fuel cells (IT-SOFCs). The intrinsic properties of phase structure, electrical conductivity, thermal expansion and oxygen adsorption capacity of La_1-xSr_xCo_0.25Fe_0.25Ni_0.25Mn_0.25O_3-δ (LSCFNM, x = 0, 0.1, 0.2, 0.3) oxides are evaluated in detail. The LSCFNM73 oxide exhibits the maximum electrical conductivity of 464 S cm⁻¹ at 800 °C and a relatively lower thermal expansion coefficient (TEC) of 15.34 × 10⁻⁶ K⁻¹, which is selected as the propriate cathode composition. The B-site of LSCFNM73 contains four elements which can increase the configuration entropy. Additionally, NiO-Yttria stabilized zirconia (YSZ) supported fuel cell is fabricated by tape casting, hot pressing-lamination, co-sintering and screen printing technologies. The fuel cell demonstrates a maximum power density of 1088 mW cm² at 800 °C, and excellent stability at 750 °C under 0.75V in 120 h and 10 times thermal cycling between 750 °C and 400 °C. Therefore, the medium-entropy LSCFNM73 oxide can be applied in IT-SOFCs as a competitive cathode material.     

Ultrafast high-temperature sintering of Li7La3Zr1.75Nb0.25Al0.15O12 (LLZO)

Rapid sintering of Li₇La₃Zr_1.75Nb_0.25Al_0.15O₁₂ (LLZO) is reported. The selection of heating elements, the effect of powder preparation and MgO additions in rapid sintered LLZO are described. Annealing LLZO powder at 750 ºC for 2 h in argon immediately before pressing helped to minimize porosity. A 15–20 s hold at 1372 ºC was sufficient to achieve densities >97%. The total sintering schedule time for rapid sintering represents a 99.7% decrease in sintering time compared to conventional sintering. At 70 °C under a pressure of 4.12 MPa cells had a critical current density of 1020 µA/cm².     

A multicomponent porous MAX phase (Ti0.25Zr0.25Nb0.25Ta0.25)2AlC: Reaction process,microstructure and pore formation mechanism

A multicomponent porous MAX phase (Ti_0.25Zr_0.25Nb_0.25Ta_0.25)₂AlC has been successfully synthesized by using pressureless sintering of mixed elemental powders. The microstructure and phase composition of the samples sintered at various temperatures have been characterized by using SEM, XRD, EDS and other analyses, from which conclusions regarding the reaction and pore forming processes could be drawn. During the whole sintering process, the pores did mainly arise from the diffusion related reactions between Al and other elements at low temperatures (below 1200 °C), and the formation reaction of the MAX phase took place at higher temperatures (above 1200 °C). An exception is the clearance holes that were left from the pressing. The optimum sintering temperature for the final MAX phase (Ti_0.25Zr_0.25Nb_0.25Ta_0.25)₂AlC was 1600 °C. A too high sintering temperature (1700 °C) caused a serious loss of Al atoms and a decomposition of the synthesized MAX phase.     

Synthesis of Ga-doped Li7La3Zr2O12 solid electrolyte with high Li+ ion conductivity

Garnet-type Li₇La₃Zr₂O₁₂ (LLZO) Li⁺ ion solid electrolyte is a promising candidate for next generation high-safety solid-state batteries. Ga-doped LLZO exhibits excellent Li⁺ ion conductivity, higher than 1 × 10^?3 S cm^?1. In this research, the doping amount of Ga, the calcination temperature of Ga-LLZO primary powders, the sintering conditions and the evolution of grains are explored to demonstrate the optimum parameters to obtain a highly conductive ceramics reproducibly via conventional solid-state reaction methods under ambient air sintering atmosphere. Cubic LLZO phase is obtained for Li_6.4Ga_0.2La₃Zr₂O₁₂ powder calcined at low temperature 850 °C. In addition, ceramic pellets sintered at 1100 °C for 320 min using this powder have relative densities higher than 94% and conductivities higher than 1.2 × 10^?3 S cm^?1 at 25 °C.     

Low-temperature synthesis of K0.5Na0.5NbO3 ceramics in a wide temperature window via cold-sintering assisted sintering method and enhanced electrical properties

High temperatures (≥ 1100 °C) and narrow temperature window (～ 20 °C) for sintering dense K_0.5Na_0.5NbO₃ ceramics always deteriorate their electrical properties. Here, via cold-sintering assisted sintering method, dense K_0.5Na_0.5NbO₃ ceramics were obtained in a wide temperature span between 800 °C and 1000 °C. An aqueous solution of NaOH and KOH mixture was used as transient liquid. Effects of liquid content (LC), molar concentration (MC) of liquid, cold-sintering temperature (T_CS), and post-annealing temperature (T_AN) on densification and electrical properties of the ceramics were investigated in detail. The ceramics prepared using LC = 10 wt%, MC = 10 mol/L, T_CS = 350 °C, and T_AN = 900 °C exhibit excellent electrical properties with d₃₃ = 123 pC/N, ε_r = 609, tanδ = 0.021, P_r = 28.0 μC/cm², P_m = 39.2 μC/cm², and E_c = 20.3 kV/cm. Compared to the ceramics with same or similar compositions via conventional solid-state sintering, the present K_0.5Na_0.5NbO₃ ceramics exhibit excellent electrical properties. The study endows the cold-sintering assisted sintering the successful method to prepare K_0.5Na_0.5NbO₃ ceramics at low temperatures and in a wide temperature window.     

Influences of Bi0.75Y0.25O1.5 addition on the microstructure and ionic conductivity of Ce0.8Y0.2O1.9 ceramics

A second phase of Y₂O₃-stabilized Bi₂O₃ (Bi_0.75Y_0.25O_1.5,YSB) is introduced into Y₂O₃-doped CeO₂ (Ce_0.8Y_0.2O_1.9,YDC) as a sintering additive and the composite ceramics of YDC-xYSB (x = 0, 5, 10, 20, 30, 40 wt%) are prepared through sintering at 1100°C for 6 h in air atmosphere. The YDC-xYSB ceramics are composed of both YDC and YSB with cubic fluorite structure, and no other impurity phases are detected in XRD patterns. The relative density of YDC-xYSB rises firstly for x ≤5 wt%, and then it declines with YSB addition from 5 to 40 wt%. The average grain size of YDC decreases from 270 nm to 85.7 nm with YSB addition from 0 to 40 wt%. The YSB phase segregates at the grain boundaries of YDC based on the TEM analysis result. The ionic conductivity of YDC-xYSB (x ≥5 wt%) is lower than that of YDC in the test temperature of 200°C–500°C, while it gradually exceeds that of YDC in 500°C–750°C. At 750°C, the conductivity of YDC-30%YSB (6.22 × 10⁻² S/cm) is 1.35 times higher than that of YDC (4.6 × 10⁻² S/cm). The YSB addition can improve the ionic conductivity of YDC in 500°C–750°C and decrease its sintering temperature.     

The degradation behavior of high-voltage SnO2 based varistors sintered at different temperatures

In this research, for the first time, the stability of SnO₂ based varistor ceramics sintered in the range of 1250–1350 °C against DC-accelerated aging and impulse surge current tests, was systematically studied. Microstructural study of the sintered samples by XRD and FESEM indicated that the sintering temperature only affects densification and grain size, while phase composition remains intact. With the increase of sintering temperature from 1250 °C to 1350 °C, the mean grain size increased from 1.6 to 8 μm. The maximum nonlinear coefficient of 50 and the minimum leakage current density of 1.5 μA/cm² were obtained in the sample sintered at 1300 °C. The breakdown electric field decreased from 800 V/mm to 270 V/mm, when sintering temperature increased from 1250 °C to 1350 °C. The samples sintered at 1250 °C did not show stability against neither of DC-accelerated aging and impulse current tests. The varistors sintered at 1300 °C exhibited the excellent resistance to DC-accelerated aging degradation, while ceramics sintered at 1350 °C showed the best resistance to impulse current degradation.     

Phase interaction and oxygen transport in La0.8Sr0.2Fe0.8Co0.2O3–(La0.9Sr0.1)0.98Ga0.8Mg0.2O3 composites

Composite ceramics made of two perovskite-type compounds, (La_0.9Sr_0.1)_0.98Ga_0.8Mg_0.2O_3−δ (LSGM) and La_0.8Sr_0.2Fe_0.8Co_0.2O_3−δ (LSFC) mixed in the ratio 60:40 wt.%, possess relatively high oxygen permeability limited by both bulk ionic conduction and surface exchange at 700−950 °C. Sintering at elevated temperatures (1320–1410 °C) necessary to obtain dense materials leads to fast interdiffusion of the components, forming almost single perovskite phase ceramics with local inhomogeneities. This phase interaction decreases the oxygen ionic transport in the composites, where the level of ionic conductivity is intermediate between those of LSGM and LSFC. The scanning electron microscopy (SEM) suggests a presence of Ga-enriched domains, probably having a high ionic conductivity. The size and concentration of these domains can be increased by decreasing sintering temperature or using preliminary coarsened LSGM powders. The maximum oxygen permeability is thus observed for the composite prepared under minimum sintering conditions sufficient to obtain gas-tight ceramics, including the use of LSGM, preliminary passivated at 1150 °C, and sintered at 1320 °C. The activation energy values for total conductivity, which is predominantly p-type electronic and slightly decreases due to component interaction, vary in the narrow range from 24.0 to 26.2 kJ/mol at 25–575 °C. The average thermal expansion coefficients (TECs) of LSGM-LSFC composites, calculated from dilatometric data in air, are (12.4–13.5)×10⁻⁶ K⁻¹ at 100–650 °C and (17.8–19.8)×10⁻⁶ K⁻¹ at 650–1000 °C.     

High thermal conductivity silicon nitride ceramics prepared by pressureless sintering with ternary sintering additives

Silicon nitride ceramics were pressureless sintered at low temperature using ternary sintering additives (TiO₂, MgO and Y₂O₃), and the effects of sintering aids on thermal conductivity and mechanical properties were studied. TiO₂–Y₂O₃–MgO sintering additives will react with the surface silica present on the silicon nitride particles to form a low melting temperature liquid phase which allows liquid phase sintering to occur and densification of the Si₃N₄. The highest flexural strength was 791(±20) MPa with 12 wt% additives sintered at 1780°C for 2 hours, comparable to the samples prepared by gas pressure sintering. Fracture toughness of all the specimens was higher than 7.2 MPa·m^1/2 as the sintering temperature was increased to 1810°C. Thermal conductivity was improved by prolonging the dwelling time and adopting the annealing process. The highest thermal conductivity of 74 W/(m∙K) was achieved with 9 wt% sintering additives sintered at 1810°C with 4 hours holding followed by postannealing.     

Improved ferroelectric,piezoelectric, and dielectric properties in pure KNN translucent ceramics by optimizing the normal sintering method

In this study, it is reported that various properties can be selectively derived in a pure (K_0.5Na_0.5)NbO₃, KNN ceramics through optimizing the sintering temperature by the conventional sintering method. High piezoelectric, ferroelectric, and dielectric properties such as d₃₃ = 127 pC/N, P_r = 31 μC/cm², and ε_r = 767 are obtained at the sintering temperature of 1100 °C. On the contrary, the specimen sintered at 1130 °C does not show high piezoelectric and ferroelectric properties, but it is translucent with a transmittance of 22% and 57% at the wavelength of 800 and 1600 nm respectively and shows a very high dielectric constant ε_r of 881. The origin of the high piezoelectric constant owes to large remanent polarization and dielectric constant, and dense microstructure with uniform distribution of large grains with the conjunction of relatively large crystal anisotropy. On the other hand, dense microstructure with almost no porosity, highly compacted grain boundaries, uniform distribution of grains, and relatively low crystalline anisotropy are responsible for the translucency and large dielectric constant of the ceramic specimens. This study demonstrates that the lead-free KNN ceramic has the potential to show multiple noteworthy properties such as piezoelectric, ferroelectric, dielectric, and transparent properties. This work provides a pure KNN ceramic simultaneously with high piezoelectric and transparent characteristics prepared only by using the conventional sintering method at a moderate sintering temperature for the first time in the literature.     

Densification and electrical conductivity of Fe and Mn-doped Ce0.83Sm0.085Nd0.085O2-& by solid-liquid method

Fe and Mn-doped Ce_0.83Sm_0.085Nd_0.085O_2-& (SNDC) powders are successfully synthesized by the simple and efficient solid-liquid method. The crystallinity and morphologies of the powders were characterized by X-ray diffractometer, Raman spectrum, and scanning electron microscopy. The effect of doping on sintering behavior, grain interior, and grain boundary conductivity are studied. The doping of Fe can effectively reduce the sintering temperature from 1450^oC to 1250°C and keep the same density. Compared with SNDC, 1 mol% Fe-doped SNDC (Fe-SNDC) sintered at 1250°C shows a higher total conductivity of 2.13 × 10⁻² S·cm^-1 at 650°C. Also, it exhibits that doping of Fe can increase the conductivity of grain interior and grain boundary simultaneously. The present work shows that the Fe-SNDC synthesized by solid-liquid method can be used as a potential electrolyte for intermediate-temperature solid oxide fuel cells.     

Achieving enhanced densification and superior ionic conductivity of garnet electrolytes via a co-doping strategy coupled with pressureless sintering

Lithium garnet oxides with 6.5 mol Li, such as Li_6.5La₃Zr_1.5(Ta/Nb)_0.5O₁₂, typically crystallise in cubic structure and exhibit excellent room-temperature ionic conductivity close to 1 mS cm^?1. However, it is challenging to densify garnet oxides. In this work, we investigated how the co-doping of tantalum (Ta) and niobium (Nb) affects the densification of pressureless sintered garnet electrolytes with compositions of Li_6.5La₃Zr_1.5Ta_(0.5?x)Nb_xO₁₂, where x = 0–0.5. The highest densification (94.5% of relative density) was achieved in Li_6.5La₃Zr_1.5Ta_0.1Nb_0.4O₁₂ (TN-LLZO) when it was sintered at 1150 °C for 6 h. This TN-LLZO garnet electrolyte delivers an ionic conductivity of 1.04 × 10^?3 S cm^?1 (at 22 °C) with a low activation energy of 0.41 eV. Our findings demonstrate that the content of dopants (Ta and Nb) plays a critical role in enhancing the sintering performance of garnet ceramics at ambient pressure.     

Phase evolution,structure, and electrochemical performance of Al-, Ga- and Ta- substituted Li7La3Zr2O12 ceramic electrolytes by a modified wet chemical route

Garnet-type Li₇La₃Zr₂O₁₂ (LLZO) is one of the most promising solid-state electrolytes (SSEs) for advanced solid-state lithium batteries (SSLBs). In this work, Li_6.25Al_0.25La₃Zr₂O₁₂, Li_6.4Ga_0.2La₃Zr₂O₁₂, and Li_6.4La₃Zr_1.4Ta_0.6O₁₂ ceramics are prepared by a modified wet chemical route. The composition of the black mixtures derived from the precursors is ascertained. The phase evolution and structural properties from the ceramic mother powders to the final ceramic electrolytes are discussed in detail. The characteristic of cubic LLZO with the space group I-43d arises in the Li_6.4Ga_0.2La₃Zr₂O₁₂ ceramic electrolyte pellet after the secondary higher-temperature (1200 °C) sintering. The Rietveld refinement reveals the roles of Al³⁺ substitution at the Li⁺ sites and Ta⁵⁺ substitution at the Zr⁴⁺ sites to adjust crystal structure. In addition, the electrochemical performance of the ceramic pellets is also investigated. Remarkably, the Li_6.4La₃Zr_1.4Ta_0.6O₁₂ ceramic electrolyte has the most outstanding electrochemical performance, showing the high ionic conductivity of 6.88 × 10^?4 S cm^?1 (25 °C), the low activation energy of 0.42 eV and an extremely low electronic conductivity of 1.77 × 10^?8 S cm^?1 (25 °C). Overall, it is supposed that this work may help to achieve high-quality modified LLZO ceramic electrolytes, especially using the wet chemical strategy.