The Experts below are selected from a list of 15468 Experts worldwide ranked by ideXlab platform
M. I. N. Isa - One of the best experts on this subject based on the ideXlab platform.
-
structural and Ionic transport properties of protonic conducting solid biopolymer electrolytes based on carboxymethyl cellulose doped with ammonium fluoride
Journal of Physical Chemistry B, 2016Co-Authors: M. A. Ramlli, M. I. N. IsaAbstract:Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and transference number measurement (TNM) techniques were applied to investigate the complexation, structural, and Ionic transport properties of and the dominant charge-carrier species in a solid biopolymer electrolyte (SBE) system based on carboxymethyl cellulose (CMC) doped with ammonium fluoride (NH4F), which was prepared via a solution casting technique. The SBEs were partially opaque in appearance, with no phase separation. The presence of interactions between the host polymer (CMC) and the Ionic dopant (NH4F) was proven by FT-IR analysis at the C–O band. XRD spectra analyzed using Origin 8 software disclose that the degree of crystallinity (χc%) of the SBEs decreased with the addition of NH4F, indicating an increase in the amorphous nature of the SBEs. Analysis of the Ionic transport properties reveals that the Ionic conductivity of the SBEs is dependent on the Ionic Mobility (μ) and diffusion of ions (D). TNM analysis confirms that the SB...
A Loidl - One of the best experts on this subject based on the ideXlab platform.
-
plastic crystalline solid state electrolytes Ionic conductivity and orientational dynamics in nitrile mixtures
Journal of Chemical Physics, 2019Co-Authors: D Reuter, P Lunkenheimer, A LoidlAbstract:Many plastic crystals, molecular solids with long-range, center-of-mass crystalline order but dynamic disorder of the molecular orientations, are known to exhibit exceptionally high Ionic conductivity. This makes them promising candidates for applications as solid-state electrolytes, e.g., in batteries. Interestingly, it was found that the mixing of two different plastic-crystalline materials can considerably enhance the Ionic dc conductivity, an important benchmark quantity for electrochemical applications. An example is the admixture of different nitriles to succinonitrile, the latter being one of the most prominent plastic-crystalline Ionic conductors. However, until now, only few such mixtures were studied. In the present work, we investigate succinonitrile mixed with malononitrile, adiponitrile, and pimelonitrile to which 1 mol. % of Li ions was added. Using differential scanning calorimetry and dielectric spectroscopy, we examine the phase behavior and the dipolar and Ionic dynamics of these systems. We especially address the mixing-induced enhancement of the Ionic conductivity and the coupling of the translational Ionic Mobility to the molecular reorientational dynamics, probably arising via a "revolving-door" mechanism.
-
plastic crystalline solid state electrolytes Ionic conductivity and orientational dynamics in nitrile mixtures
arXiv: Disordered Systems and Neural Networks, 2019Co-Authors: D Reuter, P Lunkenheimer, A LoidlAbstract:Many plastic crystals, molecular solids with long-range, center-of-mass crystalline order but dynamic disorder of the molecular orientations, are known to exhibit exceptionally high Ionic conductivity. This makes them promising candidates for applications as solid-state electrolytes, e.g., in batteries. Interestingly, it was found that the mixing of two different plastic-crystalline materials can considerably enhance the Ionic dc conductivity, an important benchmark quantity for electrochemical applications. An example is the admixture of different nitriles to succinonitrile, the latter being one of the most prominent plastic-crystalline Ionic conductors. However, until now only few such mixtures were studied. In the present work, we investigate succinonitrile mixed with malononitrile, adiponitrile, and pimelonitrile, to which 1 mol% of Li ions were added. Using differential scanning calorimetry and dielectric spectroscopy, we examine the phase behavior and the dipolar and Ionic dynamics of these systems. We especially address the mixing-induced enhancement of the Ionic conductivity and the coupling of the translational Ionic Mobility to the molecular reorientational dynamics, probably arising via a "revolving-door" mechanism.
Hideya Yoshitake - One of the best experts on this subject based on the ideXlab platform.
-
effect of cross sectional shape of pathway on ion migration in polyethylene separators for lithium ion batteries
Journal of Physical Chemistry C, 2020Co-Authors: Sahori Takeda, Yuria Saito, Ikue Kaneko, Hideya YoshitakeAbstract:Battery power performance is dominated by Ionic Mobility, i.e., the rate of ion transport in the separator between the electrodes. To elucidate the correlation between separator pathway morphology and Ionic Mobility, porous polyethylene membranes were prepared with different stretching ratios to obtain pathways of different cross-sectional shapes. The mode pore size (the most frequent pore size) increased with increasing stretching ratio without significant changes in membrane porosity. This indicates that pore size was increased by the connection of several pores, which were originally formed by volatilization of the grains of the dispersed oil, in the stretching direction. A large difference in stretching ratio between the machine direction (MD) and transverse direction (TD) led to the anisotropic cross-sectional shape of pathways, characterized by anisotropy of the elastic moduli in MD and TD (f(TD/MD)). The cross-sectional anisotropy of the pathway affected the Ionic Mobility. When f(TD/MD) exceeded f...
-
effect of cross sectional shape of pathway on ion migration in polyethylene separators for lithium ion batteries
The Journal of Physical Chemistry, 2019Co-Authors: Sahori Takeda, Yuria Saito, Ikue Kaneko, Hideya YoshitakeAbstract:Battery power performance is dominated by Ionic Mobility, i.e., the rate of ion transport in the separator between the electrodes. To elucidate the correlation between the separator pathway morphology and Ionic Mobility, porous polyethylene membranes were prepared with different stretching ratios to obtain pathways of different cross-sectional shapes. The mode pore size (the most frequent pore size) increased with an increasing stretching ratio without significant changes in the membrane porosity. This indicates that pore size was increased by the connection of several pores, which were originally formed by the volatilization of the grains of the dispersed oil, in the stretching direction. A large difference in the stretching ratio between the machine direction (MD) and transverse direction (TD) led to the anisotropic cross-sectional shape of pathways, characterized by anisotropy of the elastic moduli in MD and TD (f₍TD/MD₎). The cross-sectional anisotropy of the pathway affected the Ionic Mobility. When f₍TD/MD₎ exceeded f ≈ 0.8, the diffusion coefficients of the cations and anions decreased drastically owing to increases in cation–anion interactions and cation–membrane wall interactions in the pathways. These results suggest that pathways with an isotropic cross-section are appropriate for ion movement, with lower resistance and lower tortuosity of the pathways composed of the connected pores in the separator membrane.
Fangming Jiang - One of the best experts on this subject based on the ideXlab platform.
-
effect of microstructure morphology on li ion battery graphite anode performance electrochemical impedance spectroscopy modeling and analysis
Solid State Ionics, 2018Co-Authors: Bereket Tsegai Habte, Fangming JiangAbstract:Abstract Carbon graphite has received much attention over the last decades as the best candidate for negative Li-ion battery electrodes due to its thermal stability and optimal cycling capability. This paper aims to give a comprehensive account of the effect of microstructure morphology such as porosity, tortuosity, solid-electrolyte interface area and active material particle geometry on the overall performance of an electrode. Simulated annealing method (SAM) was used to reconstruct a virtual microstructure of a graphite anode based on different active material particle configuration. The underlying species transport and reaction kinetics of an electrochemical cell were modeled through an electrical circuit composed of different components. Simulated results show that active material particle geometry directly influences the tortuosity and specific surface area of the microstructure, thus affects the solid and electrolyte phase electronic/Ionic Mobility. Nyquist plot provided an overall impedance of Ionic and electronic diffusion over a frequency range of 0.1 mHz to 20 kHz. The semi-circle in the high-frequency region is associated with charge transfer resistance and dielectric behavior of the solid-electrolyte interface (SEI) while the 45° slope at the low-frequency region is a result of lithium diffusion into the solid electrode.
Liquan Chen - One of the best experts on this subject based on the ideXlab platform.
-
dynamic octahedral breathing in oxygen deficient ba0 9co0 7fe0 2nb0 1o3 δ perovskite performing as a cathode in intermediate temperature sofc
Inorganic Chemistry, 2016Co-Authors: Yudong Gong, Chunwen Sun, J A Alonso, M T Fernandezdiaz, Qiuan Huang, Liquan ChenAbstract:Ba0.9Co0.7Fe0.2Nb0.1O3-δ outperforms as a cathode in solid-oxide fuel cells (SOFC), at temperatures as low as 700–750 °C. The microscopical reason for this performance was investigated by temperature-dependent neutron powder diffraction (NPD) experiments. In the temperature range of 25–800 °C, Ba0.9Co0.7Fe0.2Nb0.1O3-δ shows a perfectly cubic structure (a = a0), with a significant oxygen deficiency in a single oxygen site, that substantially increases at the working temperatures of a SOFC. The anisotropic thermal motion of oxygen atoms considerably rises with T, reaching Beq ≈ 5 A2 at 800 °C, with prolate cigar-shaped, anisotropic vibration ellipsoids that suggest a dynamic breathing of the octahedra as oxygen ions diffuse across the structure by a vacancies mechanism, thus implying a significant Ionic Mobility that could be described as a molten oxygen sublattice. The test cell with a La0.8Sr0.2Ga0.83Mg0.17O3-δ electrolyte (∼300 μm in thickness)-supported configuration yields a peak power density of 0.20 ...
-
insight into the structure and functional application of the sr0 95ce0 05coo3 δ cathode for solid oxide fuel cells
Inorganic Chemistry, 2015Co-Authors: Wei Yang, Huairuo Zhang, Chunwen Sun, Lilu Liu, J A Alonso, M T Fernandezdiaz, Liquan ChenAbstract:A new perovskite cathode, Sr0.95Ce0.05CoO3−δ, performs well for oxygen-reduction reactions in solid oxide fuel cells (SOFCs). We gain insight into the crystal structure of Sr1–xCexCoO3−δ (x = 0.05, 0.1) and temperature-dependent structural evolution of Sr0.95Ce0.05CoO3−δ by X-ray diffraction, neutron powder diffraction, and scanning transmission electron microscopy experiments. Sr0.9Ce0.1CoO3−δ shows a perfectly cubic structure (a = a0), with a large oxygen deficiency in a single oxygen site; however, Sr0.95Ce0.05CoO3−δ exhibits a tetragonal perovskite superstructure with a double c axis, defined in the P4/mmm space group, that contains two crystallographically different cobalt positions, with distinct oxygen environments. The structural evolution of Sr0.95Ce0.05CoO3−δ at high temperatures was further studied by in situ temperature-dependent NPD experiments. At 1100 K, the oxygen atoms in Sr0.95Ce0.05CoO3−δ show large and highly anisotropic displacement factors, suggesting a significant Ionic Mobility. Th...
