In situ NMR measurements of the diffusion coefficients,including an estimate of signal strength,of lithium ion conductor using diffusion-weighting pulse sequence are performed in this study.A cascade bilinear model is...In situ NMR measurements of the diffusion coefficients,including an estimate of signal strength,of lithium ion conductor using diffusion-weighting pulse sequence are performed in this study.A cascade bilinear model is proposed to estimate the diffusion sensitivity factors of pulsed-field gradient using prior information of the electrochemical performance and Arrhenius constraint.The model postulates that the active lithium nuclei participating electrochemical reaction are relevant to the NMR signal intensity,when discharge rate or temperature condition is varying.The electrochemical data and the NMR signal strength show a highly fit with the proposed model according our simulation and experiments.Furthermore,the diffusion time is constrained by temperature based on Arrhenius equation of reaction rates dependence.An experimental calculation of Li_4Ti_5O_（12）（LTO）/carbon nanotubes（CNTs） with the electrolyte evaluating at 20 ℃ is presented,which the b factor is estimated by the discharge rate.展开更多
New lithium fast ion conductors of Li1.2 ＋ x - y Yx Ti1.9 - x Al0.1Si0. 1Wy P2.9 - y O12 based on LiTi2（PO4）3 were prepared by high temperature solid state reaction using refined natural kaolinite as a starting mat...New lithium fast ion conductors of Li1.2 ＋ x - y Yx Ti1.9 - x Al0.1Si0. 1Wy P2.9 - y O12 based on LiTi2（PO4）3 were prepared by high temperature solid state reaction using refined natural kaolinite as a starting material. X-ray powder diffraction analysis indicates that a phase with Nasieon-like structure exists together with other phases in the composition range of x =0.1, y≤0.2 and x =0.2,y ≤0.2. AC impedance measurements show that the initial composition with x = 0.10, y = 0.10 possesses the highest ionic conductivity of 1.65 × 10^-5 S·cm^-1 at room temperature, while the sample with initial composition of x =0.20, y =0.10 has the best ionic conductivity of 6. 53 × 10^-3S·cm^-1 at 573 K and decomposes at 3.0 V.展开更多
Perovskite type lithium fast ion conductors of Li 3 x La 0.67- x In y Ti 1-2 y P y O 3 system were prepared by solid state reaction. X ray powder diffraction shows that perovskite solid...Perovskite type lithium fast ion conductors of Li 3 x La 0.67- x In y Ti 1-2 y P y O 3 system were prepared by solid state reaction. X ray powder diffraction shows that perovskite solid solution forms in the ranges of x =0.10～0.12, y ≤0.2. AC impedance measurements indicate that the bulk conductivities and the total conductivities are of 1×10 -4 and 1× 10 -5 S·cm -1 at 25 ℃ respectively. The compositions have low bulk activation energies of 20 kJ·mol -1 in the temperature ranges of 298～523 K and total activation energies of 40 kJ·mol -1 in the temperature ranges of 298～623 K.展开更多
Natural layered aluminosilicate Kaolinite Al_(4)[Si_(4)O_(10)](OH)_(8)has been used as a starting material for preparing a new system of lithium fast ion conductors by high temperature(1073-1223 K)solid state reaction...Natural layered aluminosilicate Kaolinite Al_(4)[Si_(4)O_(10)](OH)_(8)has been used as a starting material for preparing a new system of lithium fast ion conductors by high temperature(1073-1223 K)solid state reactions.X-ray powder diffraction and a.c.impedance technique were used to characterize the compositions of the Li_(1+2x)Al_(x)Zr_(2-x)Si_(x)P_(3-x)O_(12)system.A single pure solid solution phase with R3c space group can be formed in the composition range of x≤04.A specimen with x=03 possesses a maximum ionic conductivity which reaches up to 103×10^(-2)s/cm at 723 K and the activation energy is 2963 kJ/mol.展开更多
Poly(lithium propionate methyl siloxane )as a single-ion carrier source was synthesized. The crosslinked film showed lower lithium ionic conductivity at room temperature (about 10^(-10) S/cm). However,the lithium ioni...Poly(lithium propionate methyl siloxane )as a single-ion carrier source was synthesized. The crosslinked film showed lower lithium ionic conductivity at room temperature (about 10^(-10) S/cm). However,the lithium ionic conductivity was obviously increased by blending with high polar polymers such as polyethylene oxide, poly (methylsiloxane - co- ethylene oxide) and poly (methylsiloxane- g- ethylene oxide). In the blend system a high conductivity of 10^(-7)-10^(-5) Scm^(-1) at room temperature was obtained and the single-ion conductivity was deeply influenced by the content of the poly (lithium propionate methyl siioxane). The dc ionic conductivity of the flexible crosslinked films is more stable over time.展开更多
A series of compounds, La 2/3- x Li 3 x MoO 4, were first prepared. Their structures are tetragonal scheelites with the cationic defects. The cell parameters a, c and values of c/a decrease with...A series of compounds, La 2/3- x Li 3 x MoO 4, were first prepared. Their structures are tetragonal scheelites with the cationic defects. The cell parameters a, c and values of c/a decrease with the increasing of the substitution amount (3 x ) of lithium ion. Cationic vacancies are getting more as Li + concentration is lower. The diffusion of lithium ion is predominant. The concentration of charge carriers increases with increasing the substitution amount (3 x ) of lithium ion, meanwhile, the concentration of cationic vacancies decreases. The conductivity approaches the best when the substitution amount (3 x ) of lithium ion is about 0.3. The conductivity of La 0.567 Li 0.3 MoO 4 is 6.5×10 -6 S·cm -1 at room temperature.展开更多
以LiTi2(PO4)3为母体,以天然高岭石为起始原料,经高温固相反应制得了一系列新的锂快离子导体Li1.2+x-yYxTi1.9-xAl0.1Si0.1SyP2.9-yO12(以下简称Y S Lisicon)。X射线粉末衍射分析结果表明在x≤0.3,y<(0.2+x)的组成范围内均能得到类似...以LiTi2(PO4)3为母体,以天然高岭石为起始原料,经高温固相反应制得了一系列新的锂快离子导体Li1.2+x-yYxTi1.9-xAl0.1Si0.1SyP2.9-yO12(以下简称Y S Lisicon)。X射线粉末衍射分析结果表明在x≤0.3,y<(0.2+x)的组成范围内均能得到类似于Nasicon三方结构的相,同时还存在其他杂相。应用交流阻抗技术测定电导率的结果表明起始组成为x=0.1,y=0.15的合成物电导率最高,其在室温下的电导率为2.93×10-5S·cm-1,在673K时可达3.62×10-2S·cm-1,其在473～673K间的活化能为37.19kJ·mol-1,分解电压为3.0V。展开更多
基金supported by the National Major Scientific Equipment R&D Project (No. ZDYZ2010-2)the National Natural Science Foundation of China (No. 51307165)
文摘In situ NMR measurements of the diffusion coefficients,including an estimate of signal strength,of lithium ion conductor using diffusion-weighting pulse sequence are performed in this study.A cascade bilinear model is proposed to estimate the diffusion sensitivity factors of pulsed-field gradient using prior information of the electrochemical performance and Arrhenius constraint.The model postulates that the active lithium nuclei participating electrochemical reaction are relevant to the NMR signal intensity,when discharge rate or temperature condition is varying.The electrochemical data and the NMR signal strength show a highly fit with the proposed model according our simulation and experiments.Furthermore,the diffusion time is constrained by temperature based on Arrhenius equation of reaction rates dependence.An experimental calculation of Li_4Ti_5O_（12）（LTO）/carbon nanotubes（CNTs） with the electrolyte evaluating at 20 ℃ is presented,which the b factor is estimated by the discharge rate.
文摘New lithium fast ion conductors of Li1.2 ＋ x - y Yx Ti1.9 - x Al0.1Si0. 1Wy P2.9 - y O12 based on LiTi2（PO4）3 were prepared by high temperature solid state reaction using refined natural kaolinite as a starting material. X-ray powder diffraction analysis indicates that a phase with Nasieon-like structure exists together with other phases in the composition range of x =0.1, y≤0.2 and x =0.2,y ≤0.2. AC impedance measurements show that the initial composition with x = 0.10, y = 0.10 possesses the highest ionic conductivity of 1.65 × 10^-5 S·cm^-1 at room temperature, while the sample with initial composition of x =0.20, y =0.10 has the best ionic conductivity of 6. 53 × 10^-3S·cm^-1 at 573 K and decomposes at 3.0 V.
文摘Perovskite type lithium fast ion conductors of Li 3 x La 0.67- x In y Ti 1-2 y P y O 3 system were prepared by solid state reaction. X ray powder diffraction shows that perovskite solid solution forms in the ranges of x =0.10～0.12, y ≤0.2. AC impedance measurements indicate that the bulk conductivities and the total conductivities are of 1×10 -4 and 1× 10 -5 S·cm -1 at 25 ℃ respectively. The compositions have low bulk activation energies of 20 kJ·mol -1 in the temperature ranges of 298～523 K and total activation energies of 40 kJ·mol -1 in the temperature ranges of 298～623 K.
文摘Natural layered aluminosilicate Kaolinite Al_(4)[Si_(4)O_(10)](OH)_(8)has been used as a starting material for preparing a new system of lithium fast ion conductors by high temperature(1073-1223 K)solid state reactions.X-ray powder diffraction and a.c.impedance technique were used to characterize the compositions of the Li_(1+2x)Al_(x)Zr_(2-x)Si_(x)P_(3-x)O_(12)system.A single pure solid solution phase with R3c space group can be formed in the composition range of x≤04.A specimen with x=03 possesses a maximum ionic conductivity which reaches up to 103×10^(-2)s/cm at 723 K and the activation energy is 2963 kJ/mol.
基金This work was supported by the National Natural Science Foundation of China
文摘Poly(lithium propionate methyl siloxane )as a single-ion carrier source was synthesized. The crosslinked film showed lower lithium ionic conductivity at room temperature (about 10^(-10) S/cm). However,the lithium ionic conductivity was obviously increased by blending with high polar polymers such as polyethylene oxide, poly (methylsiloxane - co- ethylene oxide) and poly (methylsiloxane- g- ethylene oxide). In the blend system a high conductivity of 10^(-7)-10^(-5) Scm^(-1) at room temperature was obtained and the single-ion conductivity was deeply influenced by the content of the poly (lithium propionate methyl siioxane). The dc ionic conductivity of the flexible crosslinked films is more stable over time.
文摘A series of compounds, La 2/3- x Li 3 x MoO 4, were first prepared. Their structures are tetragonal scheelites with the cationic defects. The cell parameters a, c and values of c/a decrease with the increasing of the substitution amount (3 x ) of lithium ion. Cationic vacancies are getting more as Li + concentration is lower. The diffusion of lithium ion is predominant. The concentration of charge carriers increases with increasing the substitution amount (3 x ) of lithium ion, meanwhile, the concentration of cationic vacancies decreases. The conductivity approaches the best when the substitution amount (3 x ) of lithium ion is about 0.3. The conductivity of La 0.567 Li 0.3 MoO 4 is 6.5×10 -6 S·cm -1 at room temperature.
文摘以LiTi2(PO4)3为母体,以天然高岭石为起始原料,经高温固相反应制得了一系列新的锂快离子导体Li1.2+x-yYxTi1.9-xAl0.1Si0.1SyP2.9-yO12(以下简称Y S Lisicon)。X射线粉末衍射分析结果表明在x≤0.3,y<(0.2+x)的组成范围内均能得到类似于Nasicon三方结构的相,同时还存在其他杂相。应用交流阻抗技术测定电导率的结果表明起始组成为x=0.1,y=0.15的合成物电导率最高,其在室温下的电导率为2.93×10-5S·cm-1,在673K时可达3.62×10-2S·cm-1,其在473～673K间的活化能为37.19kJ·mol-1,分解电压为3.0V。
