Traditional garnet solid electrolyte(Li_(7)La_(3)Zr_(2)O_(12))suffers from low room temperature ionic conductivity,poor air stability,high sintering temperature and energy consumption.Considering the development prosp...Traditional garnet solid electrolyte(Li_(7)La_(3)Zr_(2)O_(12))suffers from low room temperature ionic conductivity,poor air stability,high sintering temperature and energy consumption.Considering the development prospects of high-entropy materials with high structural disorder and strong component controllability in the field of electrochemical energy storage,herein,a novel high-entropy garnet-type oxide solid electrolyte,Li_(5.75)Ga_(0.25)La_(3)Zr_(0.5)Ti_(0.5)Sn_(0.5)Nb_(0.5)O_(12)(LGLZTSNO)was constructed by partially replacing the Li and Zr sites in Li_(7)La_(3)Zr_(2)O_(12)with Ga and Ti/Sn/Nb elements,respectively.The experimental and density functional theory(DFT)calculation results show that the high-entropy LGLZTSNO electrolyte has preferable room temperature ion conductivity,air stability,interface contact performance with lithium anode,and the ability to suppress lithium dendrites.Thanks to the improvement of electrolyte performance,the critical current density of Li/Ag@LGLZTSNO/Li symmetric cell was increased from 0.42 to 1.57 mA cm^(−2),and the interface area specific impedance(IASR)was reduced from 765.2 to 42.3Ωcm^(2).Meanwhile,the Li/Ag@LGLZTSNO/LFP full cell also exhibits excellent rate performance and cycling performance(148 mA h g^(−1)at 0.1 C and 124 mA h g^(−1)at 0.5 C,capacity retention up to 84.8%after 100 cycles at 0.1 C),showing the application prospects of high-entropy LGLZTSNO solid electrolyte in high-performance all solid state lithium batteries.展开更多
Polycrystalline samples of Zintl phase EuCd2-xMnxSb2 （0.05≤x≤0.6） with the CaAl2Si2-type crystal structure （space group P3ml） were synthesized via a solid-state reaction followed by suitable cooling, annealing a...Polycrystalline samples of Zintl phase EuCd2-xMnxSb2 （0.05≤x≤0.6） with the CaAl2Si2-type crystal structure （space group P3ml） were synthesized via a solid-state reaction followed by suitable cooling, annealing and spark plasma sintering （SPS） processes. In samples with x=0.0, 0.1, 0.2, 0.4 and 0.6, the electrical conductivity, Seebeck coefficient, and thermal conductivity were performed as a function of temperature from 300 to 650 K. It was found that chemical substitution of Mn failed to optimize the thermoelectric properties of p-type conductive EuCd2Sb2. It was because that the Mn substitution induced the minority carriers （electrons）, resulting in decreasing the electrical conductivity drastically despite the fact that it enlarged the Seebeck coefficient and reduced the thermal conductivity synchronously.展开更多
In order to obtain a safe,reliable,long-lived battery system without use of flammable,volatile,and relatively unstable organic liquid-based electrolytes,lithium garnet oxides with formulas Li7-xLa3Zr2-xTaxO12（x=0.2-1...In order to obtain a safe,reliable,long-lived battery system without use of flammable,volatile,and relatively unstable organic liquid-based electrolytes,lithium garnet oxides with formulas Li7-xLa3Zr2-xTaxO12（x=0.2-1）were synthesized by the solid state reaction method.Single cubic phases were observed in the composition x range between 0.2 and 1.The lattice parameters decreased with the addition of Ta due to the smaller ionic radius of Ta^5＋compared with that of Zr^4＋,following the Vegard＇s law.The total conductivity of the x=0.3 composition is 6.03×10^-5 S·cm^-1at room temperature with an activation energy of 0.30 eV.These lithium garnet oxides exhibit lithium ionic transport that is relevant to lithium battery application.展开更多
A series of cadmium-calcium hydroxyapatite solid solutions was prepared by an aqueous precipitation method. By various means, the characterizations confirmed the formation of continuous solid solutions over all ranges...A series of cadmium-calcium hydroxyapatite solid solutions was prepared by an aqueous precipitation method. By various means, the characterizations confirmed the formation of continuous solid solutions over all ranges of Cd/（Cd＋Ca） atomic ratio. In the results, both lattice parameters a and c display slight deviations from Vegard’s rule when the Cd/（Cd＋Ca） atomic ratio is greater than 0.6. The particles change from smaller acicular to larger hexagonal columnar crystals as the Cd/（Cd＋Ca） atomic ratio increases from 0-0.60 to 0.60-1.00. The area of the phosphate peak for symmetric P-O stretching decreases with the increase in Cd/（Cd＋Ca） atomic ratio, and the peak disappears when the Cd/（Cd＋Ca） atomic ratio is greater than 0.6; the two phosphate peaks of P-O stretching gradually merge together for the Cd/（Cd＋Ca） atomic ratio near 0.60. These variations can be explained by a slight tendency of larger Cd ions to occupy M（2） sites and smaller Ca ions to prefer M（1） sites in the structure.展开更多
Understanding the correlations between lattice dynamics(phonons) and ion transport is important for improving the ionic conductivity of solid-state electrolytes. This understanding largely hinges on selective tuning o...Understanding the correlations between lattice dynamics(phonons) and ion transport is important for improving the ionic conductivity of solid-state electrolytes. This understanding largely hinges on selective tuning or excitation of specific phonon modes without changing the chemical environments of atoms, which is, however, challenging to be achieved. In this work, we used ~6Li isotope substitution to selectively change the phonon properties associated with lithium, without introducing additional defects or disorders which would affect the ion transport properties. The changes in the phonon modes were then related to ion transport properties through impedance measurements and deep potential molecular dynamics simulations. Our results demonstrated that lower lithium vibration frequency leads to higher ionic conductivity and lower activation energy in the garnet solid-state electrolyte of Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12). We furthermore quantified the effect of lithium-related phonons on the migration entropy and attempt frequency, which would be difficult to be achieved otherwise. Our work suggests an effective isotope substitution method to decouple the effect of phonon modes to ion transport from that of other complex structural factors. The obtained insights can contribute to innovative understanding of ion transport in solids and strategies to optimize the ionic conductivity of solid-state electrolytes.展开更多
Lil.03Co0.10MnL90FxO4-x （z=0, 0.05, 0.10, 0.15 and 0.20） cathode materials were synthesized by solid-state reaction using Mn203, Li2CO3, C0203 and LiF as raw materials. The chemical compositions of Lil.03COo.lMnl.9F...Lil.03Co0.10MnL90FxO4-x （z=0, 0.05, 0.10, 0.15 and 0.20） cathode materials were synthesized by solid-state reaction using Mn203, Li2CO3, C0203 and LiF as raw materials. The chemical compositions of Lil.03COo.lMnl.9FzO4-z were examined by inductively coupled plasma （ICP） and potentiometric analysis, the effects of F-substitution contents on structure, morphology and electrochemical performance of spinel Lil.03Coo.loMnl.9004 were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical measurements. It is found that the Lix.03 Co0.10Mnl.9oFzOa_z samples display a single phase of cubic spinel structure. The lattice parameters increase with the increase of F content when z〈_0.10. However, the lattice parameters begin to decrease when F content continues to increase. The results show that an appropriate amount ofF substitution for O element with Li＋, Co3＋ improves discharge capacity and structure stability of the materials. The Lil.03Co0.10Mnl.90FoAsO3.s5 sample shows an initial discharge capacity of 111.0 mA.h/g and has capacity retention of 97.0% after 30 cycles at 0.2C.展开更多
The paper presents results of studies of the formation of phases during the solid-state synthesis in the[(Na_(0.5)Bi_(0.5)T_(0.80)Ba_(0.20)]Ti_(1-y)B_(y)TO_(3)system of solid solutions with B-site substitutions.The su...The paper presents results of studies of the formation of phases during the solid-state synthesis in the[(Na_(0.5)Bi_(0.5)T_(0.80)Ba_(0.20)]Ti_(1-y)B_(y)TO_(3)system of solid solutions with B-site substitutions.The substitutions by zirconium,tin and ion complexes(In_(0.5)Nb_(0.5)T and(Fe_(0.5)Nb_(0.5)T have been studied.It has been found that the synthesis is a multi-step process associated with the formation of a number of intermediate phases(depending on the compositions and calcination temperatures).Single-phase solid solutions have been produced at the calcination temperatures in the interval 1000–1100℃.An increase in the substituting ions concentration leads to a linear increase of the crystal cell size.At the same time,the tolerance factor gets reduced boosting the stability of the antiferroelectric phase as compared to that of the ferroelectric phase.展开更多
BaFeO_(3-δ)-derived perovskites are promising cathodes for intermediate temperature solid oxide fuel cells.The activity of these perovskites depends on the number of oxygen vacancies in their lattice,which can be tun...BaFeO_(3-δ)-derived perovskites are promising cathodes for intermediate temperature solid oxide fuel cells.The activity of these perovskites depends on the number of oxygen vacancies in their lattice,which can be tuned by cationic substitution.Our first-principle calculations show that Ag is a promising substitute for the Fe site,resulting in a reduced oxygen vacancy formation energy compared with the pristine BaFeO_(3-δ).Ag has limited solubility in perovskites,and its introduction generates an Ag metal secondary phase,which influences the cathode performances.In this work,we investigate the matter,using a Ba0:9La0:1Fe_(1-x)AgxO_(3-δ)series of materials as a case study.Acknowledging the limited solubility of Ag in Ba0:9La0:1Fe_(1-x)AgxO_(3-δ),we aim to distinguish the effects of Ag substitution from those of the Ag secondary phase.We observed that Ag substitution increases the number of oxygen vacancies,confirming our calculations,and facilitates the oxygen incorporation.However,Ag substitution lowers the number of holes,in this way reducing the electronic p-type conductivity.On the other hand,Ag metal positively affects the electronic conductivity and helps the redistribution of the electronic charge at the cathode-electrolyte interface.展开更多
Proton conducting solid oxide fuel cell(H-SOFC)is an emerging energy conversion device,with lower activation energy and higher energy utilization efficiency.However,the deficiency of highly active cathode materials st...Proton conducting solid oxide fuel cell(H-SOFC)is an emerging energy conversion device,with lower activation energy and higher energy utilization efficiency.However,the deficiency of highly active cathode materials still remains a major challenge for the development of H-SOFC.Therefore,in this work,K_(2)NiF_(4)-type cathode materials Pr_(2-x)Ba_(x)Ni_(0.6)Cu_(0.4)O_(4+δ)(x=0,0.1,0.2,0.3),single-phase tripleconducting(e-/O^(2-)/H^(+))oxides,are prepared for intermediate temperature H-SOFCs and exhibit good oxygen reduction reaction activity.The investigation demonstrates that doping Ba into Pr_(2-x)BaxNi_(0.6)Cu_(0.4)O_(4+δ) can increase its electrochemical performance through enhancing electrical conductivity,oxygen vacancy concentration and proton conductivity.EIS tests are carried at 750℃ and the minimum polarization impedances are obtained when x=0.2,which are 0.068 Ω·cm^(2) in air and 1.336 Ω·cm^(2) in wet argon,respectively.The peak power density of the cell with Pr_(1.8)Ba_(0.2)Ni_(0.6)Cu_(0.4)O_(4+δ) cathode is 298 mW·cm^(-2) at 750℃ in air with humidified hydrogen as fuel.Based on the above results,Ba-doped Pr_(2-x)Ba_(x)Ni_(0.6)Cu_(0.4)O_(4+δ) can be a good candidate material for SOFC cathode applications.展开更多
Boron for aluminum substitution in the cordierite structure has been examined by sol-gel preparation of different samples along the compositional junction Mg2Al4-xBxSi5O18 with x=0,0.5,1,1.5.By increasing the x value ...Boron for aluminum substitution in the cordierite structure has been examined by sol-gel preparation of different samples along the compositional junction Mg2Al4-xBxSi5O18 with x=0,0.5,1,1.5.By increasing the x value from 0 to 1.5 the crystallization behavior changed accordingly.Proper amount B2O3 doping can promote the sintering of amorphous cordierite gel,effectively restrain the precipitation of μ-cordierite and enhance the crystallization of α-cordierite.The substitution of B3＋ for Al3＋ in cordierite crystal structure can effectively improve the near-infrared spectral emissivity of this cordierite based glass-ceramics.展开更多
基金supported by the Natural Science Foundation of China(61901142)the Key Research and Development Project of Hainan Province(ZDYF2022SHFZ093).
文摘Traditional garnet solid electrolyte(Li_(7)La_(3)Zr_(2)O_(12))suffers from low room temperature ionic conductivity,poor air stability,high sintering temperature and energy consumption.Considering the development prospects of high-entropy materials with high structural disorder and strong component controllability in the field of electrochemical energy storage,herein,a novel high-entropy garnet-type oxide solid electrolyte,Li_(5.75)Ga_(0.25)La_(3)Zr_(0.5)Ti_(0.5)Sn_(0.5)Nb_(0.5)O_(12)(LGLZTSNO)was constructed by partially replacing the Li and Zr sites in Li_(7)La_(3)Zr_(2)O_(12)with Ga and Ti/Sn/Nb elements,respectively.The experimental and density functional theory(DFT)calculation results show that the high-entropy LGLZTSNO electrolyte has preferable room temperature ion conductivity,air stability,interface contact performance with lithium anode,and the ability to suppress lithium dendrites.Thanks to the improvement of electrolyte performance,the critical current density of Li/Ag@LGLZTSNO/Li symmetric cell was increased from 0.42 to 1.57 mA cm^(−2),and the interface area specific impedance(IASR)was reduced from 765.2 to 42.3Ωcm^(2).Meanwhile,the Li/Ag@LGLZTSNO/LFP full cell also exhibits excellent rate performance and cycling performance(148 mA h g^(−1)at 0.1 C and 124 mA h g^(−1)at 0.5 C,capacity retention up to 84.8%after 100 cycles at 0.1 C),showing the application prospects of high-entropy LGLZTSNO solid electrolyte in high-performance all solid state lithium batteries.
基金Project supported by Young Eastern Scholar Project of Shanghai Municipal Education Commission(QD2015031)
文摘Polycrystalline samples of Zintl phase EuCd2-xMnxSb2 （0.05≤x≤0.6） with the CaAl2Si2-type crystal structure （space group P3ml） were synthesized via a solid-state reaction followed by suitable cooling, annealing and spark plasma sintering （SPS） processes. In samples with x=0.0, 0.1, 0.2, 0.4 and 0.6, the electrical conductivity, Seebeck coefficient, and thermal conductivity were performed as a function of temperature from 300 to 650 K. It was found that chemical substitution of Mn failed to optimize the thermoelectric properties of p-type conductive EuCd2Sb2. It was because that the Mn substitution induced the minority carriers （electrons）, resulting in decreasing the electrical conductivity drastically despite the fact that it enlarged the Seebeck coefficient and reduced the thermal conductivity synchronously.
基金Funded by the National Natural Science Foundation of China(No.21276284)the Hunan Provincial Natural Science Foundation of China(2015JJ3074)+1 种基金the Science and Technology Project of Changsha(KL403147-11)the Postdoctoral Fund of Hunan Agricultural University(129263)
文摘In order to obtain a safe,reliable,long-lived battery system without use of flammable,volatile,and relatively unstable organic liquid-based electrolytes,lithium garnet oxides with formulas Li7-xLa3Zr2-xTaxO12（x=0.2-1）were synthesized by the solid state reaction method.Single cubic phases were observed in the composition x range between 0.2 and 1.The lattice parameters decreased with the addition of Ta due to the smaller ionic radius of Ta^5＋compared with that of Zr^4＋,following the Vegard＇s law.The total conductivity of the x=0.3 composition is 6.03×10^-5 S·cm^-1at room temperature with an activation energy of 0.30 eV.These lithium garnet oxides exhibit lithium ionic transport that is relevant to lithium battery application.
基金financially supported by the National Natural Science Foundation of China(No.41263009)the Guangxi Science and Technology Development Project(No.GuiKeZhong 1298002-3)the National Natural Science Foundation of Guangxi of China(No.2012GXNSFDA053022)
文摘A series of cadmium-calcium hydroxyapatite solid solutions was prepared by an aqueous precipitation method. By various means, the characterizations confirmed the formation of continuous solid solutions over all ranges of Cd/（Cd＋Ca） atomic ratio. In the results, both lattice parameters a and c display slight deviations from Vegard’s rule when the Cd/（Cd＋Ca） atomic ratio is greater than 0.6. The particles change from smaller acicular to larger hexagonal columnar crystals as the Cd/（Cd＋Ca） atomic ratio increases from 0-0.60 to 0.60-1.00. The area of the phosphate peak for symmetric P-O stretching decreases with the increase in Cd/（Cd＋Ca） atomic ratio, and the peak disappears when the Cd/（Cd＋Ca） atomic ratio is greater than 0.6; the two phosphate peaks of P-O stretching gradually merge together for the Cd/（Cd＋Ca） atomic ratio near 0.60. These variations can be explained by a slight tendency of larger Cd ions to occupy M（2） sites and smaller Ca ions to prefer M（1） sites in the structure.
基金supported by the National Natural Science Foundation of China(22222204).
文摘Understanding the correlations between lattice dynamics(phonons) and ion transport is important for improving the ionic conductivity of solid-state electrolytes. This understanding largely hinges on selective tuning or excitation of specific phonon modes without changing the chemical environments of atoms, which is, however, challenging to be achieved. In this work, we used ~6Li isotope substitution to selectively change the phonon properties associated with lithium, without introducing additional defects or disorders which would affect the ion transport properties. The changes in the phonon modes were then related to ion transport properties through impedance measurements and deep potential molecular dynamics simulations. Our results demonstrated that lower lithium vibration frequency leads to higher ionic conductivity and lower activation energy in the garnet solid-state electrolyte of Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12). We furthermore quantified the effect of lithium-related phonons on the migration entropy and attempt frequency, which would be difficult to be achieved otherwise. Our work suggests an effective isotope substitution method to decouple the effect of phonon modes to ion transport from that of other complex structural factors. The obtained insights can contribute to innovative understanding of ion transport in solids and strategies to optimize the ionic conductivity of solid-state electrolytes.
基金Project(2011GZ0131) supported by the Sichuan Province Key Technology Support Program,China
文摘Lil.03Co0.10MnL90FxO4-x （z=0, 0.05, 0.10, 0.15 and 0.20） cathode materials were synthesized by solid-state reaction using Mn203, Li2CO3, C0203 and LiF as raw materials. The chemical compositions of Lil.03COo.lMnl.9FzO4-z were examined by inductively coupled plasma （ICP） and potentiometric analysis, the effects of F-substitution contents on structure, morphology and electrochemical performance of spinel Lil.03Coo.loMnl.9004 were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical measurements. It is found that the Lix.03 Co0.10Mnl.9oFzOa_z samples display a single phase of cubic spinel structure. The lattice parameters increase with the increase of F content when z〈_0.10. However, the lattice parameters begin to decrease when F content continues to increase. The results show that an appropriate amount ofF substitution for O element with Li＋, Co3＋ improves discharge capacity and structure stability of the materials. The Lil.03Co0.10Mnl.90FoAsO3.s5 sample shows an initial discharge capacity of 111.0 mA.h/g and has capacity retention of 97.0% after 30 cycles at 0.2C.
文摘The paper presents results of studies of the formation of phases during the solid-state synthesis in the[(Na_(0.5)Bi_(0.5)T_(0.80)Ba_(0.20)]Ti_(1-y)B_(y)TO_(3)system of solid solutions with B-site substitutions.The substitutions by zirconium,tin and ion complexes(In_(0.5)Nb_(0.5)T and(Fe_(0.5)Nb_(0.5)T have been studied.It has been found that the synthesis is a multi-step process associated with the formation of a number of intermediate phases(depending on the compositions and calcination temperatures).Single-phase solid solutions have been produced at the calcination temperatures in the interval 1000–1100℃.An increase in the substituting ions concentration leads to a linear increase of the crystal cell size.At the same time,the tolerance factor gets reduced boosting the stability of the antiferroelectric phase as compared to that of the ferroelectric phase.
基金The authors gratefully acknowledge the Research Grant Council of Hong Kong for support through the projects 16201820,and 16206019.
文摘BaFeO_(3-δ)-derived perovskites are promising cathodes for intermediate temperature solid oxide fuel cells.The activity of these perovskites depends on the number of oxygen vacancies in their lattice,which can be tuned by cationic substitution.Our first-principle calculations show that Ag is a promising substitute for the Fe site,resulting in a reduced oxygen vacancy formation energy compared with the pristine BaFeO_(3-δ).Ag has limited solubility in perovskites,and its introduction generates an Ag metal secondary phase,which influences the cathode performances.In this work,we investigate the matter,using a Ba0:9La0:1Fe_(1-x)AgxO_(3-δ)series of materials as a case study.Acknowledging the limited solubility of Ag in Ba0:9La0:1Fe_(1-x)AgxO_(3-δ),we aim to distinguish the effects of Ag substitution from those of the Ag secondary phase.We observed that Ag substitution increases the number of oxygen vacancies,confirming our calculations,and facilitates the oxygen incorporation.However,Ag substitution lowers the number of holes,in this way reducing the electronic p-type conductivity.On the other hand,Ag metal positively affects the electronic conductivity and helps the redistribution of the electronic charge at the cathode-electrolyte interface.
基金the National Natural Science Foundation of China(Grant no.22078022).
文摘Proton conducting solid oxide fuel cell(H-SOFC)is an emerging energy conversion device,with lower activation energy and higher energy utilization efficiency.However,the deficiency of highly active cathode materials still remains a major challenge for the development of H-SOFC.Therefore,in this work,K_(2)NiF_(4)-type cathode materials Pr_(2-x)Ba_(x)Ni_(0.6)Cu_(0.4)O_(4+δ)(x=0,0.1,0.2,0.3),single-phase tripleconducting(e-/O^(2-)/H^(+))oxides,are prepared for intermediate temperature H-SOFCs and exhibit good oxygen reduction reaction activity.The investigation demonstrates that doping Ba into Pr_(2-x)BaxNi_(0.6)Cu_(0.4)O_(4+δ) can increase its electrochemical performance through enhancing electrical conductivity,oxygen vacancy concentration and proton conductivity.EIS tests are carried at 750℃ and the minimum polarization impedances are obtained when x=0.2,which are 0.068 Ω·cm^(2) in air and 1.336 Ω·cm^(2) in wet argon,respectively.The peak power density of the cell with Pr_(1.8)Ba_(0.2)Ni_(0.6)Cu_(0.4)O_(4+δ) cathode is 298 mW·cm^(-2) at 750℃ in air with humidified hydrogen as fuel.Based on the above results,Ba-doped Pr_(2-x)Ba_(x)Ni_(0.6)Cu_(0.4)O_(4+δ) can be a good candidate material for SOFC cathode applications.
基金supported by the National Nature Science Foundation of China (No. 50771014)
文摘Boron for aluminum substitution in the cordierite structure has been examined by sol-gel preparation of different samples along the compositional junction Mg2Al4-xBxSi5O18 with x=0,0.5,1,1.5.By increasing the x value from 0 to 1.5 the crystallization behavior changed accordingly.Proper amount B2O3 doping can promote the sintering of amorphous cordierite gel,effectively restrain the precipitation of μ-cordierite and enhance the crystallization of α-cordierite.The substitution of B3＋ for Al3＋ in cordierite crystal structure can effectively improve the near-infrared spectral emissivity of this cordierite based glass-ceramics.
