Ionic conduction in space charge regions. Maier, J. Progress in Solid State Chemistry, 23(3):171–263, January, 1995. ![Ionic conduction in space charge regions [link]](https://bibbase.org/img/filetypes/link.svg "link")
Paper doi abstract bibtex Thermal, structural and electrical properties of composite solid electrolytes (1-x)(C4H9)4NBF4–xAl2O3 with nanocrystalline γ-alumina were investigated by DSC, X-ray diffraction, IR spectroscopy, impedance and electrochemical measurements. It was found that the melting enthalpy of (C4H9)4NBF4 in the composites strongly decreases and its value approaches to zero in the composites with x ≥ 0.9, where x is the molar fraction of alumina, indicating the transformation of (C4H9)4NBF4 to an interface-stabilized amorphous state. This effect was quantitatively interpreted in terms of the brick-wall model assuming that a layer of amorphous phase of the ionic salt is formed at salt/oxide interfaces. At the alumina concentration of x = 0.9, corresponding to a volume fraction of alumina f = 0.53, almost all the ionic salt gets into the interface layer the thickness of the amorphous layer is nearly 3 nm. These results agree with the results of X-ray diffraction studies and IR spectroscopy. Introduction of nanocrystalline γ-alumina into the (C4H9)4NBF4 matrix leads to a relative increase in conductivity by more than 2 orders of magnitude, conductivity goes through a maximum of 0.21 mS/cm at 130 °C for the composite with x = 0.9. This composite is characterized by a non-Arrhenius temperature dependence, typical for glassy electrolytes. It was shown that the electrochemical voltage for the composite 0.1(C4H9)4NBF4–0.9Al2O3 is nearly 4 V. Solid state ionics has grown to be one of the most important directions of science, combining emerging interdisciplinary technologies for many applications. This paper begins with the brief history of solid state ionics, followed by detailed discussions on scientific problems, state-of-art theoretical and experimental methods, and promising research directions in this field. The practical applications of principles and knowledge in solid state ionics are also summarized. Complex metal hydrides have recently gained interest as solid electrolytes for all-solid-state batteries due to their light weight, easy deformability, and fast ion mobility at elevated temperatures. However, increasing their low conductivity at room temperature is a prerequisite for application. In this review, two strategies to enhance room temperature conductivity in complex metal hydrides, nanostructuring and nanocomposite formation, are highlighted. First, the recent achievements in nanostructured complex metal hydride-based ion conductors and complex metal hydride/metal oxide nanocomposite ion conductors are summarized, and the trends and challenges in their preparation are discussed. Then, the reported all-solid-state batteries based on complex metal hydride nanocomposite electrolytes are highlighted. Finally, future research directions and perspectives are proposed, both for the preparation of improved metal hydride ion conductors, as well as metal hydride-based all-solid-state batteries. Lithium tracer diffusion coefficients have been measured in Li1.3Al0.3Ti1.7(PO4)3 (LATP) and LATP – LaPO4 composite solid electrolytes in the temperature range between 300 °C and 500 °C by means of neutron radiography technique that utilizes the difference in neutron attenuation of 6Li and 7Li isotopes. The diffusion coefficient of LATP – LaPO4 composite is higher than that of pristine LATP, although the difference is much smaller than that estimated from the room temperature conductivity. This suggests that the bulk diffusion becomes the predominant diffusion mechanism at 300 °C to 500 °C instead of the diffusion along the space charge layer formed around the LaPO4 dispersants. Nanocomposite solid electrolytes (C4H9)4NBF4–MIL-101(Cr) based on pure components without any other additives were prepared and their structure and electrical properties were investigated as a function of temperature and concentration of the metal-organic framework MIL-101(Cr). According to the data of thermal analysis, the heat effect due to the melting of the salt in the composites strongly decreases and tends to zero at a molar fraction of MIL-101(Cr) x ≥ 0.34. This effect is assumed to be caused by the amorphization of the salt in the composites which is practically complete at high content of MIL-101(Cr). The dependence of the melting enthalpy on the molar or mass fraction of MIL-101(Cr) may be explained by filling of MIL-101(Cr) pores with the salt, provided that the salt residing outside the pores is crystalline, whereas the salt located inside the pores is amorphous. In this case, at some fraction of the MIL-101(Cr), x = xmax, all the salt will be located inside the pores, and the concentration of the salt occurring in an amorphous state reaches a maximum. At x \textless xmax there is a linear dependence between melting enthalpy and molar (or mass) fraction from which allows one can determine xmax and wmax values from experimental data. From these data, the volume of accessible pores was estimated as Vpore = 0.92 cm3/g corresponding to 73% of the total pore volume determined by BET adsorption method. The thermal properties fairly correlate with the X-ray diffraction data. Reflections on X-ray diffraction patterns of the composites attributed to (C4H9)4NBF4 strongly decrease with the concentration of MIL-101(Cr) and at the concentration x ≥ 0.283 practically no reflections of the salt are observed on the X-ray patterns. The electrical properties of the composites were investigated. It was shown that the concentration dependence of conductivity has a maximum at the concentration close to xmax value determined from the thermal analysis data. At x \textgreater xmax temperature dependences of conductivity are not linear in Arrhenius coordinates, no sudden conductivity change is observed due to the melting of the salt. Such conductivity behaviour is typical for amorphous electrolytes. Quantitative analysis of the concentration dependence of conductivity was done using the pore filling model and the mixing equations proposed earlier for two-phase composites. Theoretical curves obtained using the mixing equations satisfactorily fit the experimental data. The maximum value of ionic conductivity, 5∙10−4 S/cm at 135 °C, obtained for the composite 0.675(C4H9)4NBF4–0.325MIL-101(Cr) is rather high assuming that BF4− anions are the most probable charge carriers. Lithium-ion conductors with a crystal structure classified as Na super ion Conductors (NASICON) exhibit high ionic conductivity at room temperature that may be used in next-generation batteries. This study finds unusual ionic conduction of Li1.3Al0.3Ti1.7(PO4)3 (LATP): hysteresis on temperature and atmosphere dependence. The precise conductivity analyses (a wide frequency range, a wide temperature range, and a narrow temperature interval) reveal that the unusual conductivity is attributed to grain boundary conductivity enhanced by moisture. From the detailed studies on bulk (crystal structure) and grain boundary (microcracks, segregation, and impurities) of LATP pellets, it is concluded that the unusual ionic conduction results from adsorbed water on microcracks of LATP pellets. It is also confirmed that at high humidity, grain boundary resistance is further reduced by condensed water in the microcracks. This study reveals the high moisture sensitivity of conductivity of LATP for the first time, which is explained by the concerted influence of microstructure and humidity on ionic conductivity across grain boundaries. The results point out the importance of atmosphere control in scientific studies and for quality control of this class of solid electrolytes in advanced batteries like all-solid-state batteries, Li-air batteries, and others.
@article{maier_ionic_1995,
title = {Ionic conduction in space charge regions},
volume = {23},
issn = {0079-6786},
url = {https://www.sciencedirect.com/science/article/pii/007967869500004E},
doi = {10.1016/0079-6786(95)00004-E},
abstract = {Thermal, structural and electrical properties of composite solid electrolytes (1-x)(C4H9)4NBF4–xAl2O3 with nanocrystalline γ-alumina were investigated by DSC, X-ray diffraction, IR spectroscopy, impedance and electrochemical measurements. It was found that the melting enthalpy of (C4H9)4NBF4 in the composites strongly decreases and its value approaches to zero in the composites with x ≥ 0.9, where x is the molar fraction of alumina, indicating the transformation of (C4H9)4NBF4 to an interface-stabilized amorphous state. This effect was quantitatively interpreted in terms of the brick-wall model assuming that a layer of amorphous phase of the ionic salt is formed at salt/oxide interfaces. At the alumina concentration of x = 0.9, corresponding to a volume fraction of alumina f = 0.53, almost all the ionic salt gets into the interface layer the thickness of the amorphous layer is nearly 3 nm. These results agree with the results of X-ray diffraction studies and IR spectroscopy. Introduction of nanocrystalline γ-alumina into the (C4H9)4NBF4 matrix leads to a relative increase in conductivity by more than 2 orders of magnitude, conductivity goes through a maximum of 0.21 mS/cm at 130 °C for the composite with x = 0.9. This composite is characterized by a non-Arrhenius temperature dependence, typical for glassy electrolytes. It was shown that the electrochemical voltage for the composite 0.1(C4H9)4NBF4–0.9Al2O3 is nearly 4 V.
Solid state ionics has grown to be one of the most important directions of science, combining emerging interdisciplinary technologies for many applications. This paper begins with the brief history of solid state ionics, followed by detailed discussions on scientific problems, state-of-art theoretical and experimental methods, and promising research directions in this field. The practical applications of principles and knowledge in solid state ionics are also summarized.
Complex metal hydrides have recently gained interest as solid electrolytes for all-solid-state batteries due to their light weight, easy deformability, and fast ion mobility at elevated temperatures. However, increasing their low conductivity at room temperature is a prerequisite for application. In this review, two strategies to enhance room temperature conductivity in complex metal hydrides, nanostructuring and nanocomposite formation, are highlighted. First, the recent achievements in nanostructured complex metal hydride-based ion conductors and complex metal hydride/metal oxide nanocomposite ion conductors are summarized, and the trends and challenges in their preparation are discussed. Then, the reported all-solid-state batteries based on complex metal hydride nanocomposite electrolytes are highlighted. Finally, future research directions and perspectives are proposed, both for the preparation of improved metal hydride ion conductors, as well as metal hydride-based all-solid-state batteries.
Lithium tracer diffusion coefficients have been measured in Li1.3Al0.3Ti1.7(PO4)3 (LATP) and LATP – LaPO4 composite solid electrolytes in the temperature range between 300 °C and 500 °C by means of neutron radiography technique that utilizes the difference in neutron attenuation of 6Li and 7Li isotopes. The diffusion coefficient of LATP – LaPO4 composite is higher than that of pristine LATP, although the difference is much smaller than that estimated from the room temperature conductivity. This suggests that the bulk diffusion becomes the predominant diffusion mechanism at 300 °C to 500 °C instead of the diffusion along the space charge layer formed around the LaPO4 dispersants.
Nanocomposite solid electrolytes (C4H9)4NBF4–MIL-101(Cr) based on pure components without any other additives were prepared and their structure and electrical properties were investigated as a function of temperature and concentration of the metal-organic framework MIL-101(Cr). According to the data of thermal analysis, the heat effect due to the melting of the salt in the composites strongly decreases and tends to zero at a molar fraction of MIL-101(Cr) x ≥ 0.34. This effect is assumed to be caused by the amorphization of the salt in the composites which is practically complete at high content of MIL-101(Cr). The dependence of the melting enthalpy on the molar or mass fraction of MIL-101(Cr) may be explained by filling of MIL-101(Cr) pores with the salt, provided that the salt residing outside the pores is crystalline, whereas the salt located inside the pores is amorphous. In this case, at some fraction of the MIL-101(Cr), x = xmax, all the salt will be located inside the pores, and the concentration of the salt occurring in an amorphous state reaches a maximum. At x {\textless} xmax there is a linear dependence between melting enthalpy and molar (or mass) fraction from which allows one can determine xmax and wmax values from experimental data. From these data, the volume of accessible pores was estimated as Vpore = 0.92 cm3/g corresponding to 73\% of the total pore volume determined by BET adsorption method. The thermal properties fairly correlate with the X-ray diffraction data. Reflections on X-ray diffraction patterns of the composites attributed to (C4H9)4NBF4 strongly decrease with the concentration of MIL-101(Cr) and at the concentration x ≥ 0.283 practically no reflections of the salt are observed on the X-ray patterns. The electrical properties of the composites were investigated. It was shown that the concentration dependence of conductivity has a maximum at the concentration close to xmax value determined from the thermal analysis data. At x {\textgreater} xmax temperature dependences of conductivity are not linear in Arrhenius coordinates, no sudden conductivity change is observed due to the melting of the salt. Such conductivity behaviour is typical for amorphous electrolytes. Quantitative analysis of the concentration dependence of conductivity was done using the pore filling model and the mixing equations proposed earlier for two-phase composites. Theoretical curves obtained using the mixing equations satisfactorily fit the experimental data. The maximum value of ionic conductivity, 5∙10−4 S/cm at 135 °C, obtained for the composite 0.675(C4H9)4NBF4–0.325MIL-101(Cr) is rather high assuming that BF4− anions are the most probable charge carriers.
Lithium-ion conductors with a crystal structure classified as Na super ion Conductors (NASICON) exhibit high ionic conductivity at room temperature that may be used in next-generation batteries. This study finds unusual ionic conduction of Li1.3Al0.3Ti1.7(PO4)3 (LATP): hysteresis on temperature and atmosphere dependence. The precise conductivity analyses (a wide frequency range, a wide temperature range, and a narrow temperature interval) reveal that the unusual conductivity is attributed to grain boundary conductivity enhanced by moisture. From the detailed studies on bulk (crystal structure) and grain boundary (microcracks, segregation, and impurities) of LATP pellets, it is concluded that the unusual ionic conduction results from adsorbed water on microcracks of LATP pellets. It is also confirmed that at high humidity, grain boundary resistance is further reduced by condensed water in the microcracks. This study reveals the high moisture sensitivity of conductivity of LATP for the first time, which is explained by the concerted influence of microstructure and humidity on ionic conductivity across grain boundaries. The results point out the importance of atmosphere control in scientific studies and for quality control of this class of solid electrolytes in advanced batteries like all-solid-state batteries, Li-air batteries, and others.},
language = {en},
number = {3},
urldate = {2022-04-24},
journal = {Progress in Solid State Chemistry},
author = {Maier, Joachim},
month = jan,
year = {1995},
pages = {171--263},
}
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{"_id":"3j3kSqzg2D4A9p8FW","bibbaseid":"maier-ionicconductioninspacechargeregions-1995","author_short":["Maier, J."],"bibdata":{"bibtype":"article","type":"article","title":"Ionic conduction in space charge regions","volume":"23","issn":"0079-6786","url":"https://www.sciencedirect.com/science/article/pii/007967869500004E","doi":"10.1016/0079-6786(95)00004-E","abstract":"Thermal, structural and electrical properties of composite solid electrolytes (1-x)(C4H9)4NBF4–xAl2O3 with nanocrystalline γ-alumina were investigated by DSC, X-ray diffraction, IR spectroscopy, impedance and electrochemical measurements. It was found that the melting enthalpy of (C4H9)4NBF4 in the composites strongly decreases and its value approaches to zero in the composites with x ≥ 0.9, where x is the molar fraction of alumina, indicating the transformation of (C4H9)4NBF4 to an interface-stabilized amorphous state. This effect was quantitatively interpreted in terms of the brick-wall model assuming that a layer of amorphous phase of the ionic salt is formed at salt/oxide interfaces. At the alumina concentration of x = 0.9, corresponding to a volume fraction of alumina f = 0.53, almost all the ionic salt gets into the interface layer the thickness of the amorphous layer is nearly 3 nm. These results agree with the results of X-ray diffraction studies and IR spectroscopy. Introduction of nanocrystalline γ-alumina into the (C4H9)4NBF4 matrix leads to a relative increase in conductivity by more than 2 orders of magnitude, conductivity goes through a maximum of 0.21 mS/cm at 130 °C for the composite with x = 0.9. This composite is characterized by a non-Arrhenius temperature dependence, typical for glassy electrolytes. It was shown that the electrochemical voltage for the composite 0.1(C4H9)4NBF4–0.9Al2O3 is nearly 4 V. Solid state ionics has grown to be one of the most important directions of science, combining emerging interdisciplinary technologies for many applications. This paper begins with the brief history of solid state ionics, followed by detailed discussions on scientific problems, state-of-art theoretical and experimental methods, and promising research directions in this field. The practical applications of principles and knowledge in solid state ionics are also summarized. Complex metal hydrides have recently gained interest as solid electrolytes for all-solid-state batteries due to their light weight, easy deformability, and fast ion mobility at elevated temperatures. However, increasing their low conductivity at room temperature is a prerequisite for application. In this review, two strategies to enhance room temperature conductivity in complex metal hydrides, nanostructuring and nanocomposite formation, are highlighted. First, the recent achievements in nanostructured complex metal hydride-based ion conductors and complex metal hydride/metal oxide nanocomposite ion conductors are summarized, and the trends and challenges in their preparation are discussed. Then, the reported all-solid-state batteries based on complex metal hydride nanocomposite electrolytes are highlighted. Finally, future research directions and perspectives are proposed, both for the preparation of improved metal hydride ion conductors, as well as metal hydride-based all-solid-state batteries. Lithium tracer diffusion coefficients have been measured in Li1.3Al0.3Ti1.7(PO4)3 (LATP) and LATP – LaPO4 composite solid electrolytes in the temperature range between 300 °C and 500 °C by means of neutron radiography technique that utilizes the difference in neutron attenuation of 6Li and 7Li isotopes. The diffusion coefficient of LATP – LaPO4 composite is higher than that of pristine LATP, although the difference is much smaller than that estimated from the room temperature conductivity. This suggests that the bulk diffusion becomes the predominant diffusion mechanism at 300 °C to 500 °C instead of the diffusion along the space charge layer formed around the LaPO4 dispersants. Nanocomposite solid electrolytes (C4H9)4NBF4–MIL-101(Cr) based on pure components without any other additives were prepared and their structure and electrical properties were investigated as a function of temperature and concentration of the metal-organic framework MIL-101(Cr). According to the data of thermal analysis, the heat effect due to the melting of the salt in the composites strongly decreases and tends to zero at a molar fraction of MIL-101(Cr) x ≥ 0.34. This effect is assumed to be caused by the amorphization of the salt in the composites which is practically complete at high content of MIL-101(Cr). The dependence of the melting enthalpy on the molar or mass fraction of MIL-101(Cr) may be explained by filling of MIL-101(Cr) pores with the salt, provided that the salt residing outside the pores is crystalline, whereas the salt located inside the pores is amorphous. In this case, at some fraction of the MIL-101(Cr), x = xmax, all the salt will be located inside the pores, and the concentration of the salt occurring in an amorphous state reaches a maximum. At x \\textless xmax there is a linear dependence between melting enthalpy and molar (or mass) fraction from which allows one can determine xmax and wmax values from experimental data. From these data, the volume of accessible pores was estimated as Vpore = 0.92 cm3/g corresponding to 73% of the total pore volume determined by BET adsorption method. The thermal properties fairly correlate with the X-ray diffraction data. Reflections on X-ray diffraction patterns of the composites attributed to (C4H9)4NBF4 strongly decrease with the concentration of MIL-101(Cr) and at the concentration x ≥ 0.283 practically no reflections of the salt are observed on the X-ray patterns. The electrical properties of the composites were investigated. It was shown that the concentration dependence of conductivity has a maximum at the concentration close to xmax value determined from the thermal analysis data. At x \\textgreater xmax temperature dependences of conductivity are not linear in Arrhenius coordinates, no sudden conductivity change is observed due to the melting of the salt. Such conductivity behaviour is typical for amorphous electrolytes. Quantitative analysis of the concentration dependence of conductivity was done using the pore filling model and the mixing equations proposed earlier for two-phase composites. Theoretical curves obtained using the mixing equations satisfactorily fit the experimental data. The maximum value of ionic conductivity, 5∙10−4 S/cm at 135 °C, obtained for the composite 0.675(C4H9)4NBF4–0.325MIL-101(Cr) is rather high assuming that BF4− anions are the most probable charge carriers. Lithium-ion conductors with a crystal structure classified as Na super ion Conductors (NASICON) exhibit high ionic conductivity at room temperature that may be used in next-generation batteries. This study finds unusual ionic conduction of Li1.3Al0.3Ti1.7(PO4)3 (LATP): hysteresis on temperature and atmosphere dependence. The precise conductivity analyses (a wide frequency range, a wide temperature range, and a narrow temperature interval) reveal that the unusual conductivity is attributed to grain boundary conductivity enhanced by moisture. From the detailed studies on bulk (crystal structure) and grain boundary (microcracks, segregation, and impurities) of LATP pellets, it is concluded that the unusual ionic conduction results from adsorbed water on microcracks of LATP pellets. It is also confirmed that at high humidity, grain boundary resistance is further reduced by condensed water in the microcracks. This study reveals the high moisture sensitivity of conductivity of LATP for the first time, which is explained by the concerted influence of microstructure and humidity on ionic conductivity across grain boundaries. The results point out the importance of atmosphere control in scientific studies and for quality control of this class of solid electrolytes in advanced batteries like all-solid-state batteries, Li-air batteries, and others.","language":"en","number":"3","urldate":"2022-04-24","journal":"Progress in Solid State Chemistry","author":[{"propositions":[],"lastnames":["Maier"],"firstnames":["Joachim"],"suffixes":[]}],"month":"January","year":"1995","pages":"171–263","bibtex":"@article{maier_ionic_1995,\n\ttitle = {Ionic conduction in space charge regions},\n\tvolume = {23},\n\tissn = {0079-6786},\n\turl = {https://www.sciencedirect.com/science/article/pii/007967869500004E},\n\tdoi = {10.1016/0079-6786(95)00004-E},\n\tabstract = {Thermal, structural and electrical properties of composite solid electrolytes (1-x)(C4H9)4NBF4–xAl2O3 with nanocrystalline γ-alumina were investigated by DSC, X-ray diffraction, IR spectroscopy, impedance and electrochemical measurements. It was found that the melting enthalpy of (C4H9)4NBF4 in the composites strongly decreases and its value approaches to zero in the composites with x ≥ 0.9, where x is the molar fraction of alumina, indicating the transformation of (C4H9)4NBF4 to an interface-stabilized amorphous state. This effect was quantitatively interpreted in terms of the brick-wall model assuming that a layer of amorphous phase of the ionic salt is formed at salt/oxide interfaces. At the alumina concentration of x = 0.9, corresponding to a volume fraction of alumina f = 0.53, almost all the ionic salt gets into the interface layer the thickness of the amorphous layer is nearly 3 nm. These results agree with the results of X-ray diffraction studies and IR spectroscopy. Introduction of nanocrystalline γ-alumina into the (C4H9)4NBF4 matrix leads to a relative increase in conductivity by more than 2 orders of magnitude, conductivity goes through a maximum of 0.21 mS/cm at 130 °C for the composite with x = 0.9. This composite is characterized by a non-Arrhenius temperature dependence, typical for glassy electrolytes. It was shown that the electrochemical voltage for the composite 0.1(C4H9)4NBF4–0.9Al2O3 is nearly 4 V.\nSolid state ionics has grown to be one of the most important directions of science, combining emerging interdisciplinary technologies for many applications. This paper begins with the brief history of solid state ionics, followed by detailed discussions on scientific problems, state-of-art theoretical and experimental methods, and promising research directions in this field. The practical applications of principles and knowledge in solid state ionics are also summarized.\nComplex metal hydrides have recently gained interest as solid electrolytes for all-solid-state batteries due to their light weight, easy deformability, and fast ion mobility at elevated temperatures. However, increasing their low conductivity at room temperature is a prerequisite for application. In this review, two strategies to enhance room temperature conductivity in complex metal hydrides, nanostructuring and nanocomposite formation, are highlighted. First, the recent achievements in nanostructured complex metal hydride-based ion conductors and complex metal hydride/metal oxide nanocomposite ion conductors are summarized, and the trends and challenges in their preparation are discussed. Then, the reported all-solid-state batteries based on complex metal hydride nanocomposite electrolytes are highlighted. Finally, future research directions and perspectives are proposed, both for the preparation of improved metal hydride ion conductors, as well as metal hydride-based all-solid-state batteries.\nLithium tracer diffusion coefficients have been measured in Li1.3Al0.3Ti1.7(PO4)3 (LATP) and LATP – LaPO4 composite solid electrolytes in the temperature range between 300 °C and 500 °C by means of neutron radiography technique that utilizes the difference in neutron attenuation of 6Li and 7Li isotopes. The diffusion coefficient of LATP – LaPO4 composite is higher than that of pristine LATP, although the difference is much smaller than that estimated from the room temperature conductivity. This suggests that the bulk diffusion becomes the predominant diffusion mechanism at 300 °C to 500 °C instead of the diffusion along the space charge layer formed around the LaPO4 dispersants.\nNanocomposite solid electrolytes (C4H9)4NBF4–MIL-101(Cr) based on pure components without any other additives were prepared and their structure and electrical properties were investigated as a function of temperature and concentration of the metal-organic framework MIL-101(Cr). According to the data of thermal analysis, the heat effect due to the melting of the salt in the composites strongly decreases and tends to zero at a molar fraction of MIL-101(Cr) x ≥ 0.34. This effect is assumed to be caused by the amorphization of the salt in the composites which is practically complete at high content of MIL-101(Cr). The dependence of the melting enthalpy on the molar or mass fraction of MIL-101(Cr) may be explained by filling of MIL-101(Cr) pores with the salt, provided that the salt residing outside the pores is crystalline, whereas the salt located inside the pores is amorphous. In this case, at some fraction of the MIL-101(Cr), x = xmax, all the salt will be located inside the pores, and the concentration of the salt occurring in an amorphous state reaches a maximum. At x {\\textless} xmax there is a linear dependence between melting enthalpy and molar (or mass) fraction from which allows one can determine xmax and wmax values from experimental data. From these data, the volume of accessible pores was estimated as Vpore = 0.92 cm3/g corresponding to 73\\% of the total pore volume determined by BET adsorption method. The thermal properties fairly correlate with the X-ray diffraction data. Reflections on X-ray diffraction patterns of the composites attributed to (C4H9)4NBF4 strongly decrease with the concentration of MIL-101(Cr) and at the concentration x ≥ 0.283 practically no reflections of the salt are observed on the X-ray patterns. The electrical properties of the composites were investigated. It was shown that the concentration dependence of conductivity has a maximum at the concentration close to xmax value determined from the thermal analysis data. At x {\\textgreater} xmax temperature dependences of conductivity are not linear in Arrhenius coordinates, no sudden conductivity change is observed due to the melting of the salt. Such conductivity behaviour is typical for amorphous electrolytes. Quantitative analysis of the concentration dependence of conductivity was done using the pore filling model and the mixing equations proposed earlier for two-phase composites. Theoretical curves obtained using the mixing equations satisfactorily fit the experimental data. The maximum value of ionic conductivity, 5∙10−4 S/cm at 135 °C, obtained for the composite 0.675(C4H9)4NBF4–0.325MIL-101(Cr) is rather high assuming that BF4− anions are the most probable charge carriers.\nLithium-ion conductors with a crystal structure classified as Na super ion Conductors (NASICON) exhibit high ionic conductivity at room temperature that may be used in next-generation batteries. This study finds unusual ionic conduction of Li1.3Al0.3Ti1.7(PO4)3 (LATP): hysteresis on temperature and atmosphere dependence. The precise conductivity analyses (a wide frequency range, a wide temperature range, and a narrow temperature interval) reveal that the unusual conductivity is attributed to grain boundary conductivity enhanced by moisture. From the detailed studies on bulk (crystal structure) and grain boundary (microcracks, segregation, and impurities) of LATP pellets, it is concluded that the unusual ionic conduction results from adsorbed water on microcracks of LATP pellets. It is also confirmed that at high humidity, grain boundary resistance is further reduced by condensed water in the microcracks. This study reveals the high moisture sensitivity of conductivity of LATP for the first time, which is explained by the concerted influence of microstructure and humidity on ionic conductivity across grain boundaries. The results point out the importance of atmosphere control in scientific studies and for quality control of this class of solid electrolytes in advanced batteries like all-solid-state batteries, Li-air batteries, and others.},\n\tlanguage = {en},\n\tnumber = {3},\n\turldate = {2022-04-24},\n\tjournal = {Progress in Solid State Chemistry},\n\tauthor = {Maier, Joachim},\n\tmonth = jan,\n\tyear = {1995},\n\tpages = {171--263},\n}\n\n","author_short":["Maier, J."],"key":"maier_ionic_1995","id":"maier_ionic_1995","bibbaseid":"maier-ionicconductioninspacechargeregions-1995","role":"author","urls":{"Paper":"https://www.sciencedirect.com/science/article/pii/007967869500004E"},"metadata":{"authorlinks":{}}},"bibtype":"article","biburl":"https://bibbase.org/zotero/hexane","dataSources":["PMupqmDbRNFndeT5W"],"keywords":[],"search_terms":["ionic","conduction","space","charge","regions","maier"],"title":"Ionic conduction in space charge regions","year":1995}