https://orcid.org/0000-0001-8103-3514
Figures & data
Table 1. List of total conductivity and used crucible for LLZO with different substitutions.
Figure 1. Development of LLZO based solid electrolyte. (a) Crystal structure of cubic Li7La3Zr2O12 (top) and coordination polyhedra around the Li(1) and Li(2) sites (bottom)[Citation4]. Reproduced with permission[Citation4]. Copyright 2011, Elsevier. (b) The loop structures constructed by Li atomic arrangement in cubic (top) and tetragonal (bottom) Li7La3Zr2O12 with occupancy value g for each site in the parenthesis[Citation4]. Reproduced with permission[Citation4]. Copyright 2011, Elsevier. (c) A phase transition from cubic to tetragonal Li7La3Zr2O12 when Li increase from 6.24 mole to 7.32 mole[Citation10]. Reproduced with permission[Citation10]. Copyright 2012, Elsevier. (d) The effect of Li-ion concentration to bulk ionic conductivities in various garnet-type Li3+xLa3M2O12 at RT[Citation11]. Reproduced with permission[Citation11]. Copyright (2012), American Physical Society.
![Figure 1. Development of LLZO based solid electrolyte. (a) Crystal structure of cubic Li7La3Zr2O12 (top) and coordination polyhedra around the Li(1) and Li(2) sites (bottom)[Citation4]. Reproduced with permission[Citation4]. Copyright 2011, Elsevier. (b) The loop structures constructed by Li atomic arrangement in cubic (top) and tetragonal (bottom) Li7La3Zr2O12 with occupancy value g for each site in the parenthesis[Citation4]. Reproduced with permission[Citation4]. Copyright 2011, Elsevier. (c) A phase transition from cubic to tetragonal Li7La3Zr2O12 when Li increase from 6.24 mole to 7.32 mole[Citation10]. Reproduced with permission[Citation10]. Copyright 2012, Elsevier. (d) The effect of Li-ion concentration to bulk ionic conductivities in various garnet-type Li3+xLa3M2O12 at RT[Citation11]. Reproduced with permission[Citation11]. Copyright (2012), American Physical Society.](/cms/asset/0d868b1a-598c-4e02-ae76-76f1b2e45531/ymte_a_1746539_f0001_oc.jpg)
Figure 2. Development of LLZO based solid electrolyte. (a) Total conductivity of LLZO with different substitutions. (b) TEM image (top) and selected-area electron diffraction pattern (bottom) of LLZO around a triple-point grain boundary[Citation13]. LiAlSiO4 is acuminated at the grain boundary. Reproduced with permission[Citation13]. Copyright 2011, Elsevier. (c) Solid state 71Ga NMR spectra of Li6.55+yGa0.15La3Zr2−yScyO12 to show Ga3+ has preference to 24d Li(1) sites[Citation15]. Reproduced with permission[Citation15]. Copyright 2017, American Chemical Society. (d) Mössbauer spectra show Fe-ions of Li7−3xFexLa3Zr2O12 at 295 K have a preference to 24d Li(1) sites[Citation112]. Reproduced with permission[Citation112]. Copyright 2013, American Chemical Society.
![Figure 2. Development of LLZO based solid electrolyte. (a) Total conductivity of LLZO with different substitutions. (b) TEM image (top) and selected-area electron diffraction pattern (bottom) of LLZO around a triple-point grain boundary[Citation13]. LiAlSiO4 is acuminated at the grain boundary. Reproduced with permission[Citation13]. Copyright 2011, Elsevier. (c) Solid state 71Ga NMR spectra of Li6.55+yGa0.15La3Zr2−yScyO12 to show Ga3+ has preference to 24d Li(1) sites[Citation15]. Reproduced with permission[Citation15]. Copyright 2017, American Chemical Society. (d) Mössbauer spectra show Fe-ions of Li7−3xFexLa3Zr2O12 at 295 K have a preference to 24d Li(1) sites[Citation112]. Reproduced with permission[Citation112]. Copyright 2013, American Chemical Society.](/cms/asset/21656eb7-4d2f-43c7-a225-409bb12559be/ymte_a_1746539_f0002_oc.jpg)
Figure 3. LLZO chemical stability toward metallic Li. (a) First principle calculated electrochemical window (solid color bar) of the solid electrolyte and other materials. The oxidation potential to fully delithiate the material is marked by the dashed line[Citation54]. Reproduced with permission[Citation54]. Copyright 2015, American Chemical Society. (b) A photograph to show that the interface of Nb-substituted LLZO were reduced by Li metal (black color) after in contact for 60 days while Ta-substituted LLZO stayed the same color[Citation55]. Reproduced with permission[Citation55]. Copyright 2015, Elsevier. (c) Raman mapping of the Li6.4Fe0.2La3Zr2O12; the picture (left) shows a cross section after the solid electrolyte has been in contact with metallic Li, spectra for different areas of the cross section (top right) and magnification of the shaded area in spectra. [Citation112] Reproduced with permission[Citation112]. Copyright 2018, American Chemical Society.
![Figure 3. LLZO chemical stability toward metallic Li. (a) First principle calculated electrochemical window (solid color bar) of the solid electrolyte and other materials. The oxidation potential to fully delithiate the material is marked by the dashed line[Citation54]. Reproduced with permission[Citation54]. Copyright 2015, American Chemical Society. (b) A photograph to show that the interface of Nb-substituted LLZO were reduced by Li metal (black color) after in contact for 60 days while Ta-substituted LLZO stayed the same color[Citation55]. Reproduced with permission[Citation55]. Copyright 2015, Elsevier. (c) Raman mapping of the Li6.4Fe0.2La3Zr2O12; the picture (left) shows a cross section after the solid electrolyte has been in contact with metallic Li, spectra for different areas of the cross section (top right) and magnification of the shaded area in spectra. [Citation112] Reproduced with permission[Citation112]. Copyright 2018, American Chemical Society.](/cms/asset/d6547088-b709-4deb-8dd1-ddf1168b6645/ymte_a_1746539_f0003_oc.jpg)
Figure 4. LLZO chemical stability toward metallic Li. (a) HAADF-STEM image of c-LLZO in situ contacted with Li (left). The O K-edges obtained in the EELS line scan (middle). Schematic illustration of the interfacial behavior suggested by the EELS line scan (right)[Citation56]. Reproduced with permission[Citation56]. Copyright 2016, American Chemical Society. (b) Nb 3d and Zr 3d core level XPS spectra from Nb-, Al-, and Ta-doped LLZO with unpolished (top), polished (middle) and UHV heated (bottom) surfaces before (red) and after (blue) Li deposition[Citation57]. Reproduced with permission[Citation57]. Copyright 2019, Wiley-VCH.
![Figure 4. LLZO chemical stability toward metallic Li. (a) HAADF-STEM image of c-LLZO in situ contacted with Li (left). The O K-edges obtained in the EELS line scan (middle). Schematic illustration of the interfacial behavior suggested by the EELS line scan (right)[Citation56]. Reproduced with permission[Citation56]. Copyright 2016, American Chemical Society. (b) Nb 3d and Zr 3d core level XPS spectra from Nb-, Al-, and Ta-doped LLZO with unpolished (top), polished (middle) and UHV heated (bottom) surfaces before (red) and after (blue) Li deposition[Citation57]. Reproduced with permission[Citation57]. Copyright 2019, Wiley-VCH.](/cms/asset/7691e228-3680-4a75-a5bf-2bd67d48b9e0/ymte_a_1746539_f0004_oc.jpg)
Figure 5. The development of a negative electrode for CLBs. (a) SEM Li dendrite structure in cycled LLZO (I) illustration of a fractured surface due to Li dendrite, (II) SEM image of a fracture surface, (III) enlarged SEM micrograph of the boxed area B in (II), (IV) higher magnification SEM image of the web structure in (III), and (V) SEM images of the web structure after exposure to air[Citation64]. Reproduced with permission[Citation64]. Copyright 2017, Elsevier. (b) Optical microscopy images of a polished single crystal of LLZTO. The white silhouette is the propagate crack that created by Li dendrite[Citation66]. Reproduced with permission[Citation66]. Copyright 2017, Wiley-VCH. (c) illustration of Li dendrite formation due to inhomogeneous contact between LLZO and Li electrode that can be solved by a Au interlayer coating[Citation60]. Reproduced with permission[Citation60]. Copyright 2016, American Chemical Society. (d) XPS scan of C 1 s, O 1 s, Zr 3d, and Li 1 s spectra collected in 200 mTorr of Ar at RT: 25°C (bottom) and 250°C (top). The C(CO3) peak at 290 eV completely disappeared indicates Li2CO3 can be remove from LLZO surface by heating up to 250°C[Citation69]. Reproduced with permission[Citation69]. Copyright 2018, American Chemical Society. (e) Contact angle between LLZO and molten Li with Li2CO3 (top) and without Li2CO3 by fine polishing and heat treatment at 500°C (bottom)[Citation16]. Reproduced with permission[Citation16]. Copyright 2017, American Chemical Society.
![Figure 5. The development of a negative electrode for CLBs. (a) SEM Li dendrite structure in cycled LLZO (I) illustration of a fractured surface due to Li dendrite, (II) SEM image of a fracture surface, (III) enlarged SEM micrograph of the boxed area B in (II), (IV) higher magnification SEM image of the web structure in (III), and (V) SEM images of the web structure after exposure to air[Citation64]. Reproduced with permission[Citation64]. Copyright 2017, Elsevier. (b) Optical microscopy images of a polished single crystal of LLZTO. The white silhouette is the propagate crack that created by Li dendrite[Citation66]. Reproduced with permission[Citation66]. Copyright 2017, Wiley-VCH. (c) illustration of Li dendrite formation due to inhomogeneous contact between LLZO and Li electrode that can be solved by a Au interlayer coating[Citation60]. Reproduced with permission[Citation60]. Copyright 2016, American Chemical Society. (d) XPS scan of C 1 s, O 1 s, Zr 3d, and Li 1 s spectra collected in 200 mTorr of Ar at RT: 25°C (bottom) and 250°C (top). The C(CO3) peak at 290 eV completely disappeared indicates Li2CO3 can be remove from LLZO surface by heating up to 250°C[Citation69]. Reproduced with permission[Citation69]. Copyright 2018, American Chemical Society. (e) Contact angle between LLZO and molten Li with Li2CO3 (top) and without Li2CO3 by fine polishing and heat treatment at 500°C (bottom)[Citation16]. Reproduced with permission[Citation16]. Copyright 2017, American Chemical Society.](/cms/asset/3d317f1b-38cf-41fd-9658-ec63a0d9593d/ymte_a_1746539_f0005_oc.jpg)
Table 2. List of interface modifications and symmetric cell test conditions for LLZOs.
Figure 6. The development of negative electrode for CLBs. (a) Galvanostatic cycling of Li/LLZO/Li at 2.2 mA·cm−2 for 0.88 mA h·cm−2 for 100 cycles[Citation71]. Reproduced with permission[Citation71]. Copyright 2019, Wiley-VCH. (b) Morphology of the lithium metal electrode before assembling the symmetric cell (I) and after stripping at 100 μA·cm−2 anodic load (III). The potential profile and impedance contributions shows a complete contact loss of Li electrode after around 12 h of stripping (II). (c) Schematic of the different mechanisms that facilitate charge transfer at the lithium metal electrode under anodic load (limiting cases)[Citation92]. (I) local current density does not exceed the vacancy diffusion limit. (II, III) local current density exceeds the diffusion limit (IV) external pressure is applied[Citation92]. Reproduced with permission[Citation92]. Copyright 2019, American Chemical Society.
![Figure 6. The development of negative electrode for CLBs. (a) Galvanostatic cycling of Li/LLZO/Li at 2.2 mA·cm−2 for 0.88 mA h·cm−2 for 100 cycles[Citation71]. Reproduced with permission[Citation71]. Copyright 2019, Wiley-VCH. (b) Morphology of the lithium metal electrode before assembling the symmetric cell (I) and after stripping at 100 μA·cm−2 anodic load (III). The potential profile and impedance contributions shows a complete contact loss of Li electrode after around 12 h of stripping (II). (c) Schematic of the different mechanisms that facilitate charge transfer at the lithium metal electrode under anodic load (limiting cases)[Citation92]. (I) local current density does not exceed the vacancy diffusion limit. (II, III) local current density exceeds the diffusion limit (IV) external pressure is applied[Citation92]. Reproduced with permission[Citation92]. Copyright 2019, American Chemical Society.](/cms/asset/cb7d3c36-9bc9-41b9-92df-08e5d7bf6628/ymte_a_1746539_f0006_oc.jpg)
Figure 7. The development of positive electrode for CLBs. (a) Cross-sectional TEM image of an LLZ/PLD deposited LCO thin film interface (top) and the EDS line profile (bottom)[Citation97]. Reproduced with permission[Citation97]. Copyright 2011, Elsevier. (b) TEM images of crystalline LCO/LLZO that was directly obtained from LCOon a LLZO pellet and the corresponding EDS elemental mappings to show Al3+ diffused into LCO after heat treated at 700°C[Citation96]. Reproduced with permission[Citation96]. Copyright 2013, American Chemical Society. (c) High-resolution micro-Raman mapping of a CLB cross-section which was sintered at 1050°C in air. (I) Optical image of the SSLB cross-section and its mapping area. The Raman mappings and the spectra for (II) LCO, (III) LLZ:Ta and (IV) epoxy[Citation99]. Reproduced with permission[Citation99]. Copyright 2019, Royal Society of Chemistry.
![Figure 7. The development of positive electrode for CLBs. (a) Cross-sectional TEM image of an LLZ/PLD deposited LCO thin film interface (top) and the EDS line profile (bottom)[Citation97]. Reproduced with permission[Citation97]. Copyright 2011, Elsevier. (b) TEM images of crystalline LCO/LLZO that was directly obtained from LCOon a LLZO pellet and the corresponding EDS elemental mappings to show Al3+ diffused into LCO after heat treated at 700°C[Citation96]. Reproduced with permission[Citation96]. Copyright 2013, American Chemical Society. (c) High-resolution micro-Raman mapping of a CLB cross-section which was sintered at 1050°C in air. (I) Optical image of the SSLB cross-section and its mapping area. The Raman mappings and the spectra for (II) LCO, (III) LLZ:Ta and (IV) epoxy[Citation99]. Reproduced with permission[Citation99]. Copyright 2019, Royal Society of Chemistry.](/cms/asset/edc9b89f-5d59-4ba9-a1f0-daf888bfdee3/ymte_a_1746539_f0007_oc.jpg)
Table 3. List of composition of the positive electrode for all-ceramic Li batteries and their test conductions.
Figure 8. The development of positive electrode for CLBs. (a) Cross-sectional SEM images of secondary electron (top) and backscattering electron (bottom) images of the interface between the positive electrode layer (LCO positive active electrode material and Li3BO3 solid electrolyte) and the Li6.75La3Zr1.75Nb0.25O12 solid electrolyte[Citation106]. Reproduced with permission[Citation106]. Copyright 2013, Elsevier. (b) Thermally soldering LCO and LLZO through the reaction between the Li2.3C0.7B0.3O3 and the Li2CO3 that can be spontaneously coated Li2.3-xC0.7+xB0.3-xO3 interphase on both LLZO and LCO. The CLB with such a CPE exhibits high cycling stability and high rate performance[Citation104]. Reproduced with permission[Citation104]. Copyright 2018, Cell.(c) CLB using LCO/LLZTaO as CPE allows high discharge current densities and capacities[Citation99]. Reproduced with permission[Citation99]. Copyright 2019, Royal Society of Chemistry. (d) Cross-sectional SEM images and EDX mapping of a LiNi1/3Co1/3Mn1/3O2 (NMC)-LATP composite film on Si/SiO2 wafer by aerosol deposition (left). TEM image of a NMC/LATP interface in the NMC-LATP composite film and its EDX line profiles to show no interface reaction between NMC and LATP during aerosol deposition[Citation115]. Reproduced with permission[Citation115]. Copyright 2016, Elsevier.
![Figure 8. The development of positive electrode for CLBs. (a) Cross-sectional SEM images of secondary electron (top) and backscattering electron (bottom) images of the interface between the positive electrode layer (LCO positive active electrode material and Li3BO3 solid electrolyte) and the Li6.75La3Zr1.75Nb0.25O12 solid electrolyte[Citation106]. Reproduced with permission[Citation106]. Copyright 2013, Elsevier. (b) Thermally soldering LCO and LLZO through the reaction between the Li2.3C0.7B0.3O3 and the Li2CO3 that can be spontaneously coated Li2.3-xC0.7+xB0.3-xO3 interphase on both LLZO and LCO. The CLB with such a CPE exhibits high cycling stability and high rate performance[Citation104]. Reproduced with permission[Citation104]. Copyright 2018, Cell.(c) CLB using LCO/LLZTaO as CPE allows high discharge current densities and capacities[Citation99]. Reproduced with permission[Citation99]. Copyright 2019, Royal Society of Chemistry. (d) Cross-sectional SEM images and EDX mapping of a LiNi1/3Co1/3Mn1/3O2 (NMC)-LATP composite film on Si/SiO2 wafer by aerosol deposition (left). TEM image of a NMC/LATP interface in the NMC-LATP composite film and its EDX line profiles to show no interface reaction between NMC and LATP during aerosol deposition[Citation115]. Reproduced with permission[Citation115]. Copyright 2016, Elsevier.](/cms/asset/ccd64b40-2493-4266-82ca-fc9c221e57de/ymte_a_1746539_f0008_oc.jpg)