Patent Application
20240194934
The present disclosure claims the benefit of the filing date of Korean Patent Application No. 10-2022-0172814, filed with the Korean Intellectual Property Office on Dec. 12, 2022, all of which are included in the present disclosure. The present disclosure relates to a solid electrolyte composition for a triple-doped garnet-type all-solid-state battery, a solid electrolyte for a triple-doped garnet-type all-solid-state battery using the same, and a method for preparing the solid electrolyte for a triple-doped garnet-type all-solid-state battery and, more particularly, to a solid electrolyte composition for a triple-doped garnet-type all-solid-state battery, comprising a Li-based compound, a La-based compound, and a Zr-based compound, and comprising an Al-based compound, a Ga-based compound, and a Ta-based compound for doping, a solid electrolyte for a triple-doped garnet-type all-solid-state battery, which contains Li, La, and Zr, and is doped with Al, Ga, and Ta, and a method for preparing the solid electrolyte for a triple-doped garnet-type all-solid-state battery.
Lithium ion batteries (LIBs) have been commercialized and widely applied to various energy storage systems such as electric transportation and portable electronic devices. Lithium ion batteries having a Li-rich liquid electrolyte exhibit high lithium ionic conductivities. However, several serious safety issues can arise during charging and discharging, such as uncontrolled exothermic reactions, self-ignition, or chemical leakage due to excessive charging and internal short circuits. Currently, all-solid-state lithium-ion batteries (ASSLIBs) containing a solid electrolyte are promising candidates that will replace conventional lithium-ion batteries in terms of wide application in different power sources with low risk and high reliability. The all-solid-state lithium-ion batteries exhibit excellent characteristics such as high safety, high power density, low chemical leakage, long cycle life, and low self-charging rate compared to lithium-ion batteries.
To date, extensive research for preparing and developing various types of solid electrolytes having relatively high Li-ion conductivities has been conducted. Among them, Li-garnet type Li7La3Zr2O12 (LLZO) has been widely studied due to various advantages such as high ionic conductivity, good thermal stability, excellent chemical stability to Li metal, and wide ranges of operating temperatures and voltages. LLZO includes two stable forms of a cubic phase and a tetragonal phase. The cubic phase LLZO exhibits a higher ionic conductivity (about 104 S·cm−1 at room temperature) when it is compared to the tetragonal phase LLZO (about 106 S·cm−1 at room temperature). Therefore, for high performance all-solid-state lithium-ion batteries, it is essential to fabricate LLZO with a high ratio of the cubic phase. In order to obtain cubic phase LLZO with a very high conductivity, several studies have attempted to extend the sintering time (typically 24 hours or more) in a temperature range of 1,000 to 1,200° C. For the optimal performance of LLZO, extensive investigations related to Li site and Zr site doping were performed on a small number of trivalent cations (Ga3+, Al3+) and supervalent cations (Ta5+, Bi5+, Nb5+, Sb5+), respectively, thereby improving the Li-ion conductivity of LLZO by stabilizing the highly conductive phase (cubic phase) and increasing the Li vacancy concentration. Each dopant plays a specific role in modifying the characteristics of LLZO by stabilizing the cubic phase. For example, Al doping at Li+ sites increases Li vacancies in the crystal structure to stabilize the cubic phase, and Al addition aids sintering to improve the density of pellets. Ga doping has an effect similar to Al substitution, but it can stabilize the cubic phase of LLZO at a low sintering temperature of about 1,000° C., and some previous studies have pointed out that Ga-doped LLZO exhibits a relatively high Li-ion conductivity compared to other doping elements of Li+ sites. In addition, Ta substitution at the Zr site stabilizes the highly conductive cubic phase. Furthermore, Ta substitution, as in Al doping, will not hinder Li ion migration, and Ta is stable compared to Li. However, systematic studies of the effect of multiple doping on phase content or ionic conductivity for LLZO are still rare and difficult to understand. In addition, a large loss of Li occurs during the sintering process for a long time, and secondary phases such as La2Zr2O7 are formed so that the ionic conductivity of LLZO is reduced. In order to prevent loss of Li during preparation, it is necessary to carefully control the initial concentration of Li, and a short sintering process at an appropriate temperature should be considered.
A technical problem to be achieved by the present disclosure is to provide a solid electrolyte composition for a triple-doped garnet-type all-solid-state battery through triple doping and appropriate control of the initial Li+ concentration, a solid electrolyte for a triple-doped garnet-type all-solid-state battery, having excellent ionic conductivity and high relative density, and a method for preparing the solid electrolyte for a triple-doped garnet-type all-solid-state battery.
However, the problems to be solved by the present disclosure are not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.
One embodiment of the present disclosure provides a solid electrolyte composition for a triple-doped garnet-type all-solid-state battery, which comprises a Li-based compound, a La-based compound, and a Zr-based compound, and comprises an Al-based compound, a Ga-based compound, and a Ta-based compound for doping.
According to one embodiment of the present disclosure, the Li-based compound included in the Li-based compound, the La-based compound, and the Zr-based compound may have a mole fraction of 0.57 or more and 0.63 or less.
One embodiment of the present disclosure provides a method for preparing a solid electrolyte for a triple-doped garnet-type all-solid-state battery, the method comprising: a mixing step of preparing a mixture by mixing a solid electrolyte composition for a triple-doped garnet-type all-solid-state battery; a calcination step of calcining the mixture; and a pulverization step of pulverizing the calcined mixture to prepare a pulverized material.
According to one embodiment of the present disclosure, the method may further comprise: a compression step of compressing the pulverized material to form it into pellets; and a sintering step of sintering the pellets.
According to one embodiment of the present disclosure, the calcination step may be performing heat treatment at a temperature of 800° C. or more and 1,000° C. or less for 1 hour or more and 10 hours or less.
According to one embodiment of the present disclosure, the pulverization step may be performing plane surface ball milling at a speed of 200 rpm or more and 500 rpm or less.
According to one embodiment of the present disclosure, the pulverized material may have an average particle size of 0.5 μm or more and 3 μm or less.
According to one embodiment of the present disclosure, the compression step may have a pressure of 100 MPa or more and 300 MPa or less.
According to one embodiment of the present disclosure, the sintering step may be performing heat treatment at a temperature of 1,100° C. or more and 1,300° C. or less for a time of 30 minutes or more and 50 minutes or less.
One embodiment of the present disclosure provides a solid electrolyte for a triple-doped garnet-type all-solid-state battery, which contains Li, La, and Zr and is doped with Al, Ga, and Ta.
According to one embodiment of the present disclosure, the solid electrolyte for the all-solid-state battery may have a structure of Formula 1 below.
LiaAlbGacLa3ZrdTaeO12 [Formula 1]
in Formula 1, 5.5≤a≤8.0, 0.18≤b≤0.24, 0.06≤c≤0.08, 1.75≤d≤1.90, and 0.01≤e≤0.02.
According to one embodiment of the present disclosure, the solid electrolyte for the all-solid-state battery may have an ionic conductivity of 3.0×10−4 S·cm−1 or more and 5.0×10−4 S·cm−1 or less.
According to one embodiment of the present disclosure, the solid electrolyte for the all-solid-state battery may contain a cubic phase and a tetragonal phase, wherein the cubic phase is contained in an amount of 75% by weight or more and 85% by weight or less.
According to one embodiment of the present disclosure, the solid electrolyte for the all-solid-state battery may have a relative density of 97% or more calculated by Equation 1 below.
Relative density (%)=real density of solid electrolyte for triple-doped garnet-type all-solid-state battery/theoretical density of solid electrolyte for triple-doped garnet-type all-solid-state battery [Equation 1]
According to one embodiment of the present disclosure, the solid electrolyte for the all-solid-state battery may be a powder-type or pellet-type solid electrolyte for a triple-doped garnet-type all-solid-state battery.
The solid electrolyte for a triple-doped garnet-type all-solid-state battery can be prepared within a short sintering time through a method for preparing a solid electrolyte for a triple-doped garnet-type all-solid-state battery, comprising triple doping (Al/Ga/Ta) and control of initial Li+ concentration according to one embodiment of the present disclosure.
The solid electrolyte for a triple-doped garnet-type all-solid-state battery according to one embodiment of the present disclosure may have high ionic conductivity and high relative density even with a short sintering time.
In the present specification, when a certain part “includes” a certain component, this means that other components may be further included without excluding other components unless otherwise stated.
In the present specification, “A and/or B” means “A and B, or A or B”.
In the present specification, “A_X” may mean LLZO doped with X mol of element A, and “A/B_X” may mean LLZO doped with X mol of element A and element B.
In the present specification, “garnet-type” may mean including both a cubic phase and a tetragonal phase, respectively.
Hereinafter, the present disclosure will be described in more detail.
One embodiment of the present disclosure is a solid electrolyte composition for a triple-doped garnet-type all-solid-state battery, which comprises a Li-based compound, a La-based compound, and a Zr-based compound, and comprises an Al-based compound, a Ga-based compound, and a Ta-based compound for doping.
In the solid electrolyte composition for a triple-doped garnet-type all-solid-state battery according to one embodiment of the present disclosure, a cubic phase is present to be predominant over a tetragonal phase. Specifically, it can be confirmed that the solid electrolyte composition for the garnet-type all-solid-state battery has a cubic phase of 73.7% and 72.9%, respectively, in Al doping and triple (Al/Ga/Ta) doping.
According to one embodiment of the present disclosure, a solid electrolyte composition for a triple-doped garnet-type all-solid-state battery comprises a Li-based compound, a La-based compound, and a Zr-based compound. The Li-based compound may include a lithium-based carbide (Li2CO3) and a lithium-based hydrate (LiOH). The La-based compound may include a lanthanum-based oxide (La2O3) and a lanthanum-based hydrate (La(OH)3). The Zr-based compound may include a zirconium-based oxide (ZrO2).
According to one embodiment of the present disclosure, a solid electrolyte composition for a triple-doped garnet-type all-solid-state battery may comprise an Al-based compound, a Ga-based compound, and a Ta-based compound for doping. The Al-based compound may include an aluminum oxide (Al2O3). The Ga-based compound may include a gallium-based oxide (Ga2O3). The Ta-based compound may include a tantalum-based oxide (Ta2O5).
According to one embodiment of the present disclosure, the Li-based compound included in the Li-based compound, the La-based compound, and the Zr-based compound in the solid electrolyte composition for a triple-doped garnet-type all-solid-state battery may have a mole fraction of 0.57 or more and 0.63 or less. Specifically, the chemical formula of the solid electrolyte composition for a triple-doped garnet-type all-solid-state battery was Li7−3a(AlGa)aLa3Zr2−bTabO12, wherein a was fixed to 0.25, and b was fixed to 0.018. At this time, the molar ratio of the Li-based compound, the La-based compound, and the Zr-based compound was Li:La:Zr=6.25:3:2, and this was used as a standard. Raw materials of the Li-based compound, La-based compound, and Zr-based compound have a Li:La:Zr molar ratio of x:3:2, and when the x value is 6.9, 7.7, and 8.4, 10.4%, 23.2%, and 34.4% of excess Li may be contained, respectively, compared to when the x value is 6.25. For example, when the x value is 6.9, 6.9/6.25=110.4%, and 10.4% of excess Li will be contained, when the x value is 7.7, 7.7/6.25=123.2, and 23.2% of excess Li will be contained, and when the x value is 8.4, 8.4/6.25=134.4%, and 34.4% of excess Li will be contained. Therefore, if the mole fraction of the Li-based compound is calculated as x/(x+3+2) using the Li:La:Zr molar ratio of x:3:2, and x values of 6.9, 7.7, and 8.4 are substituted, the Li-based compound will have a mole fraction value of 0.57 or more and 0.63 or less. In this way, triple doping is possible by containing the Li-based compound in an excessive amount of 10% to 35%. In addition, it is possible to prepare a solid electrolyte for a garnet-type all-solid-state battery having excellent ionic conductivity by comprising the Li-based compound in an excessive amount of 10% to 35%, and thus reducing Li loss occurring in the calcination step and the sintering step.
According to one embodiment of the present disclosure, the mole fraction of the Li-based compound included in the Li-based compound, the La-based compound, and the Zr-based compound in the solid electrolyte composition for a triple-doped garnet-type all-solid-state battery may satisfy [Equation a] and [Equation b].
Mole of Li-based compound:mole of La-based compound:mole of Zr-based compound=x:3:2 [Equation a]
0.57≤x/(x+3+2)≤0.63 [Equation b]
One embodiment of the present disclosure is a method for preparing a solid electrolyte for a triple-doped garnet-type all-solid-state battery, which comprises: a mixing step of preparing a mixture by mixing the solid electrolyte composition for a triple-doped garnet-type all-solid-state battery; a calcination step of calcining the mixture; and a pulverization step of pulverizing the calcined mixture to prepare a pulverized material.
According to one embodiment of the present disclosure, the method may further comprise: a compression step of compressing the pulverized material to form it into pellets; and a sintering step of sintering the pellets.
According to one embodiment of the present disclosure, the mixing step (S10) of preparing a mixture by mixing the solid electrolyte composition for a triple-doped garnet-type all-solid-state battery may be a step of mixing a sample of chemical formula Lix−0.75Al0.172Ga0.072La3Zr1.982Ta0.018O12 comprising the Li-based compound, the La-based compound, and the Zr-based compound, and comprising an Al-based compound, a Ga-based compound, and a Ta-based compound for doping using ball milling. Specifically, the mixing step (S10) may be mixing the sample in ethanol (concentration: 99.9% by weight) at 250 rpm for 6 hours using planetary ball milling.
According to one embodiment of the present disclosure, the calcination step (S30) of calcining the mixture may be performing heat treatment at a temperature of 800° C. or more and 1,000° C. or less for 1 hour or more and 10 hours or less. Preferably, the calcination step (S30) may be performing heat treatment at a temperature of 850° C. or more and 950° C. or less for 5 hours or more and 7 hours or less. Specifically, the powder sample obtained through the mixing step (S10) may be dried and then calcined at 900° C. for 6 hours to obtain an initial stage of LLZO.
According to one embodiment of the present disclosure, the pulverization step (S50) of pulverizing the calcined mixture to prepare a pulverized material may be performing plane surface ball milling at a speed of 200 rpm or more and 500 rpm or less. Preferably, the pulverization step (S50) may be performing plane surface ball milling at a speed of 200 rpm or more and 300 rpm or less for 1 hour or more and 3 hours or less. Specifically, since a decrease in the cubic phase and an increase in the tetragonal phase are shown when the rotational speed of the ball milling process, which is the pulverization step, is increased, a powder sample obtained through the calcination step (S30) may be plane surface-ball milled at a speed of 200 rpm for 2 hours in order to optimize the quality of the mother powder (composition) for pellet production.
According to one embodiment of the present disclosure, the pulverized material obtained through the pulverization step (S50) may have an average particle size of 0.5 μm or more and 3 μm or less. Preferably, the pulverized material may have an average particle size of 0.7 μm or more and 1.7 μm or less. In the case of pellets manufactured using particles larger than 3 μm, performing sintering at low energies alone is not sufficient to completely sinter the particles, whereas performing sintering at high energies can lead to porous grain boundaries between large particles, which can be advantageous for the growth of lithium dendrites, leading to short circuits in cells.
According to one embodiment of the present disclosure, the compression step (S70) of compressing the pulverized material to form it into pellets may be to manufacture pellets by applying a pressure to the pulverized material obtained through the pulverizing step (S50). The pressure applied to the pulverized material in the compression step (S70) may be 100 MPa or more and 300 MPa or less. Preferably, the compression step (S70) may be performing compression at a pressure of 200 MPa. When performing compression at the above pressure in the compression step (S70), it is possible to prepare a high energy density electrolyte since the energy density increases.
According to one embodiment of the present disclosure, the sintering step (S90) of sintering the pellets may be heat-treating the pellets manufactured in the compression step (S70) at a temperature of 1,100° C. or more and 1,300° C. or less for a time of 30 minutes or more and 50 minutes or less. Specifically, the sintering step (S90) may be covering the pellets with the same mother powder (composition) and heat-treating the pellets covered with the same mother powder (composition) at 1,250° C. for 40 minutes in a MgO crucible. In order to prevent volatilization of lithium in the solid electrolyte due to exposure to high temperatures for a long time, the pellets are covered with the same mother powder (composition) and heat-treated.
One embodiment of the present disclosure is a solid electrolyte for a triple-doped garnet-type all-solid-state battery, which contains Li, La, and Zr, and is doped with Al, Ga, and Ta.
According to one embodiment of the present disclosure, the solid electrolyte for the all-solid-state battery may have a chemical structure of LiaAlbGacLa3ZrdTaeO12 (5.5≤a≤8.0, 0.18≤b≤0.24, 0.06≤c≤0.08, 1.75≤d≤1.90, and 0.01≤e≤0.02). For example, the solid electrolyte for the all-solid-state battery may have a chemical structure of Li6.46Al0.21Ga0.07La3Zr1.83Ta0.02O12, Li5.66Al0.23Ga0.08La3Zr1.77Ta0.02O12, Li6.98Al0.23Ga0.07La3Zr1.88Ta0.02O12, Li6.47Al0.22Ga0.07La3Zr1.82Ta0.02O12, Li7.95Al0.23Ga0.07La3Zr1.85Ta0.02O12, or Li6.75Al0.19Ga0.06La3Zr1.79Ta0.01O12.
According to one embodiment of the present disclosure, the solid electrolyte for the all-solid-state battery may have an ionic conductivity of 3.0×10−4 S·cm−1 or more and 5.0×10−4 S·cm−1 or less. Specifically, the solid electrolyte for the all-solid-state battery having a chemical structure of Li6.47Al0.22Ga0.07La3Zr1.82Ta0.02O12 may have an ionic conductivity of 3.6×10−4 S·cm−1 or more.
According to one embodiment of the present disclosure, the solid electrolyte for the all-solid-state battery contains a cubic phase and a tetragonal phase, and the cubic phase may be contained in an amount of 75% by weight or more and 85% by weight or less. Specifically, the cubic phase may be contained in an amount of about 79.8% by weight in the solid electrolyte for the all-solid-state battery having a chemical structure of Li6.47Al0.22Ga0.07La3Zr1.82Ta0.02O12.
According to one embodiment of the present disclosure, the solid electrolyte for the all-solid-state battery may have a relative density of 97% or more calculated by Equation 1 below.
Relative density (%)=real density of solid electrolyte for triple-doped garnet-type all-solid-state battery/theoretical density of solid electrolyte for triple-doped garnet-type all-solid-state battery [Equation 1]
Preferably, the relative density may be 97% or more and 99% or less. Specifically, a solid electrolyte for an all-solid-state battery having a chemical structure of Li6.47Al0.22Ga0.07La3Zr1.82Ta0.02O12 may have a relative density of 97.84%.
According to one embodiment of the present disclosure, the solid electrolyte for the all-solid-state battery may be in a powder or pellet form. A solid electrolyte for a triple-doped garnet-type all-solid-state battery which contains Li, La, and Zr and is doped with Al, Ga, and Ta may include a powder or pellet form, and ionic conductivity and relative density may be improved through compression and sintering steps.
Hereinafter, embodiments will be described in detail in order to explain the present disclosure in detail. However, embodiments according to the present disclosure can be modified in many different forms, and the scope of the present disclosure is not construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present disclosure to a person having ordinary skill in the art.
Li2CO3 (KOJUNDO, 99.99%), La2O3 (KOJUNDO, 99.9%), ZrO2 (KOJUNDO, 98%), Al2O3 nanoparticles (Sigma-Aldrich, particle size of less than 50 nm), Ga2O3 (KOJUNDO, 99.99%), and Ta2O5 (KOJUNDO, 99.99%) were used in the preparation of a solid electrolyte. Due to hygroscopicity of La2O3, the raw materials were heated at 900° C. for 12 hours and then pulverized to remove the absorbed moisture. The raw materials were weighed with an excess Li of 10.4%, 23.2%, and 34.4%, respectively, with x-values of 6.9, 7.7, and 8.4 at a Li:La:Zr molar ratio of x:3:2. In the case of LLZO doped with Al, a certain amount of Al2O3 powder was added in order to achieve 0.25 mol of Al in one unit formula of LLZO samples with different Li doping levels (Al_6.9, Al_7.7, and Al_8.4), and the theoretical formula was Lix−0.75Al0.25La3Z2O12. In order to prepare triple-doped LLZO, Al2O3, Ga2O3, and Ta2O5 were added to obtain samples with a chemical formula of Lix−0.75Al0.172Ga0.072La3Zr1.982Ta0.018O12, and these samples indicated initial Li+ concentrations (AGT_6.9, AGT_7.7, and AGT_8.4) as standard. All precursor materials were mixed in ethanol (concentration: 99.9% by weight) at 250 rpm for 6 hours by planetary ball milling, and after drying, the powder sample was calcined at 900° C. for 6 hours to obtain an initial stage of LLZO. The calcined powder was pulverized again at different rotational speeds (200, 300, 400, and 500 rpm) for 2 hours and compressed at a pressure of 200 MPa to manufacture pellets. The obtained pellets were covered with the same mother powder (composition) in a MgO crucible (sintering furnace) and sintered at 1,250° C. for 40 minutes to prepare samples. Finally, all pellet samples were polished and stored in a glove box.
The phase compositions of all powder and pellet samples were analyzed through X-ray diffraction (XRD) analysis using a D8 ADVANCE instrument (BRUKER, Karlsruhe, Germany) with a Cu Kα radiation source (40 kV and 40 mA). In order to refine the crystal structure, the XRD Rietveld refinement method was applied using the High Score Plus computer program (Malvern Panalytical Ltd., Malvern, Malvern, UK). The morphological characteristics of the samples were analyzed using a field-emission scanning electron microscopy (FE-SEM) system (HITachi S-4800, Tokyo, Japan). The densities of the pellet samples were measured using the Archimedes method together with water. The elemental compositions of the samples were analyzed using inductively coupled plasma-atomic emission spectroscopy (ICP-AES, Avio500, Perkin-Elmer, Waltham, MA, USA). The average particle sizes (particle sizes) of the powder samples were measured using a laser scattering particle size analyzer (PSA, Helos KFS-MAGIC, Sympatec GmbH, Clausthal-Zellerfeld, Germany). The ionic conductivities of all pellet samples were measured in the frequency range of 1 Hz to 10 MHz using an impedance spectrometer (IVIUM potentiostat/galvanostat, IVIUM technologies, Eindhoven, The Netherlands). Both mirror-polished surfaces of all pellet samples were coated with a silver paste (resistivity: ˜ 104 (2 cm), and then connected to an impedance spectrometer through an electric wire. Ionic conductivity measurements were performed at various temperatures (25° C. to 80° C.).
In order to optimize the quality of these powders for pellet production, the effect of ball milling conditions in the pulverization step on the structural and morphological characteristics of the mother powder was investigated. For such an optimization, two types of doped LLZO with an initial Li+ concentration of 6.9 mol were used.
As shown in
As shown in
The phase compositions of all powder and pellet samples were analyzed using the XRD Rietveld refinement method, and
As shown in
Table 2 above shows the Li contents of Al-doped LLZO and triple (Al/Ga/Ta)-doped LLZO powders and sintered pellets analyzed by ICP-AES measurement. As shown in
Al_8.4 and AGT_8.4 in
As shown in
As shown in Table 3 above and
The linear shapes in
Regarding high-speed densification, there are several previous studies applying different advanced methods in order to reduce the duration of the sintering process. A list of rapidly sintered LLZO pellets is summarized in
In the present disclosure, the modification of the LLZO components was focused on by adding three different dopants (Al, Ga, and Ta) and controlling the initial Li content while applying a cost-efficient and accessible conventional fabrication process. A sintering furnace was applied at 1,250° C. for a short time (40 minutes), and the ionic conductivity of the best sample (AGT_7.7) was 0.36 mS·cm−1 (see Table 3 above). This sample also has a very high relative density (97.84%) (see Table 3 above), and the cross-sectional SEM image of the pellets shows small closed pores and a surface which is dense in such a degree that a spacing between individual grains may be almost negligible. In addition, the pellets were stabilized with a high ratio of the cubic phase (˜80%) in the structure after sintering (
As a result, in the present disclosure, a solid-state LLZO electrolyte was synthesized in a short sintering time with triple doping (Al/Ga/Ta) and an initial Li concentration. The synergistic effects of initial Li content and triple doping on the crystal structure and Li-ion conductivity of LLZO were investigated and compared with Al-doped LLZO. The results showed a phase transition and change in the density of the pellets at different initial Li contents. In addition, effective Li substitution and reduced Li loss were observed in pellets manufactured with triple doping at optimized initial Li concentrations after calcination and sintering, respectively. This shows the importance of initial Li concentration and triple doping in the preparation of LLZO electrolytes with high ionic conductivities. High-quality LLZO pellets with the most excellent ionic conductivity of 3.6×10−4 S·cm−1 and high relative density (97.8%) were obtained based on such synergistic effects. In addition, it is noteworthy that the percentage of the cubic phase in the crystal structure of LLZO was calculated and the purity of the crystal phase was investigated based on the XRD Rietveld refinement method. Such an approach has hardly been investigated in the previous documents and cannot be specifically provided through XRD patterns alone. Thus, the present disclosure in the field of LLZO not only controls the manufacturing process, but also customizes the phase components of the final product more efficiently, and this can reduce the cost and energy required in research and manufacturing. Furthermore, the present disclosure will be able to contribute to future research related to LLZO electrolytes with high ionic conductivity and a short sintering process.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0172814 | Dec 2022 | KR | national |
