scholarly journals Exploring Aliovalent Substitutions in the Lithium Halide Superionic Conductor Li3-xIn1-xZrxCl6 (0 ≤ X ≤ 0.5)

Author(s):  
Bianca Helm ◽  
Roman Schlem ◽  
Bjöern Wankmiller ◽  
Ananya Banik ◽  
Ajay Gautam ◽  
...  

<p>In recent years, ternary halides Li<sub>3</sub><i>MX</i><sub>6</sub> (<i>M</i> = Y, Er, In; <i>X</i> = Cl, Br, I) have garnered attention as solid electrolytes due to their wide electrochemical stability window and favorable room-temperature conductivities. In this material class, the influences of iso- or aliovalent substitutions are so far rarely studied in-depth, despite this being a common tool for correlating structure and transport properties. In this work, we investigate the impact of Zr substitution on the structure and ionic conductivity of Li<sub>3</sub>InCl<sub>6</sub> (Li<sub>3-<i>x</i></sub>In<sub>1-<i>x</i></sub>Zr<i><sub>x</sub></i>Cl<sub>6</sub> with 0 ≤ <i>x</i> ≤ 0.5) using a combination of neutron diffraction, nuclear magnetic resonance and impedance spectroscopy. Analysis of high-resolution diffraction data shows the presence of an additional tetrahedrally coordinated lithium position together with cation site-disorder, both of which have not been reported previously for Li<sub>3</sub>InCl<sub>6</sub>. This Li<sup>+</sup> position and cation disorder lead to the formation of a three-dimensional lithium ion diffusion channel, instead of the expected two-dimensional diffusion. Upon Zr<sup>4+</sup> substitution, the structure exhibits non-uniform volume changes along with an increasing number of vacancies, all of which lead to an increasing ionic conductivity in this series of solid solutions.</p>

2021 ◽  
Author(s):  
Bianca Helm ◽  
Roman Schlem ◽  
Bjöern Wankmiller ◽  
Ananya Banik ◽  
Ajay Gautam ◽  
...  

<p>In recent years, ternary halides Li<sub>3</sub><i>MX</i><sub>6</sub> (<i>M</i> = Y, Er, In; <i>X</i> = Cl, Br, I) have garnered attention as solid electrolytes due to their wide electrochemical stability window and favorable room-temperature conductivities. In this material class, the influences of iso- or aliovalent substitutions are so far rarely studied in-depth, despite this being a common tool for correlating structure and transport properties. In this work, we investigate the impact of Zr substitution on the structure and ionic conductivity of Li<sub>3</sub>InCl<sub>6</sub> (Li<sub>3-<i>x</i></sub>In<sub>1-<i>x</i></sub>Zr<i><sub>x</sub></i>Cl<sub>6</sub> with 0 ≤ <i>x</i> ≤ 0.5) using a combination of neutron diffraction, nuclear magnetic resonance and impedance spectroscopy. Analysis of high-resolution diffraction data shows the presence of an additional tetrahedrally coordinated lithium position together with cation site-disorder, both of which have not been reported previously for Li<sub>3</sub>InCl<sub>6</sub>. This Li<sup>+</sup> position and cation disorder lead to the formation of a three-dimensional lithium ion diffusion channel, instead of the expected two-dimensional diffusion. Upon Zr<sup>4+</sup> substitution, the structure exhibits non-uniform volume changes along with an increasing number of vacancies, all of which lead to an increasing ionic conductivity in this series of solid solutions.</p>


2019 ◽  
Vol 22 (1) ◽  
pp. 173-179
Author(s):  
Thanh Dinh Duc ◽  
Anh My-Thi Nguyen ◽  
Tru Nhi Nguyen ◽  
Hang Thi La ◽  
Phung My Loan Le

Introduction: LiFePO4/C composites were synthesized via physical mixing assisted solvothermal process. Different kinds of carbon materials were investigated including 0D (carbon Ketjen black), 1D (carbon nanotubes) and 2D (graphene) materials. X-rays diffraction patterns of carbon coated LiFePO4 synthesized by solvothermal was indexed to pure crystalline phase without the emergence of second phase. LiFePO4 platelets and rods were in range size of 80-200 nm and dispersed well in carbon matrix. The lithium ion diffusion kinetics was evaluated through the calculated diffusion coefficients to explore the impact of carbon mixing. Methods: In this work, we studied the structure, morphologies and the lithium ion diffusion kinetic of LiFePO4/C composites for Li-ion batteries. Different characterization methods were used including powder X-rays (for crystalline structure); Transmission Electron Microscopy (for particle and morphologies observation) and Cyclic voltammetry (for electrochemical kinetic study). Results: The study indicated LiFePO4/C composites were successfully obtained by mixing process and the electrochemical performance throughout the calculated diffusion coefficient was significantly improved by adding the carbon types. Conclusion: The excellent ion diffusion was obtained for composites LiFePO4/Ketjen black (KB) and LiFePO4/CNT compared to LiFePO4/Graphene. KB could be a potential candidate for large-scale production due to low-cost, stable and high electrochemical performance.  


2020 ◽  
Vol 128 (8) ◽  
pp. 453-456
Author(s):  
Tsuyoshi TAKAMI ◽  
Yoshihisa ISHIKAWA ◽  
Masao YONEMURA ◽  
Toshiharu FUKUNAGA ◽  
Eiichiro MATSUBARA ◽  
...  

1997 ◽  
Vol 496 ◽  
Author(s):  
M. Inaba ◽  
S. Nohmi ◽  
A. Funabiki ◽  
T. Abe ◽  
Z. Ogumi

ABSTRACTThe electrochemical permeation method was applied to the determination of the diffusion coefficient of Li+ion (DLi+) in a glassy carbon (GC) plate. The cell was composed of two compartments, which were separated by the GC plate. Li+ions were inserted electrochemically from one face, and extracted from the other. The flux of the permeated Li+ions was monitored as an oxidation current at the latter face. The diffusion coefficient was determined by fitting the transient current curve with a theoretical one derived from Fick's law. When the potential was stepped between two potentials in the range of 0 to 0.5 V, transient curves were well fitted with the theoretical one, which gaveDLi+ values on the order of 10−8cm2s−1. In contrast, when the potential was stepped between two potentials across 0.5 V, significant deviation was observed. The deviation indicated the presence of trap sites as well as diffusion sites for Li+ions, the former of which is the origin of the irreversible capacity of GC.


Ceramics ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 421-436
Author(s):  
Aamir Iqbal Waidha ◽  
Vanita Vanita ◽  
Oliver Clemens

Composite electrolytes containing lithium ion conducting polymer matrix and ceramic filler are promising solid-state electrolytes for all solid-state lithium ion batteries due to their wide electrochemical stability window, high lithium ion conductivity and low electrode/electrolyte interfacial resistance. In this study, we report on the polymer infiltration of porous thin films of aluminum-doped cubic garnet fabricated via a combination of nebulized spray pyrolysis and spin coating with subsequent post annealing at 1173 K. This method offers a simple and easy route for the fabrication of a three-dimensional porous garnet network with a thickness in the range of 50 to 100 µm, which could be used as the ceramic backbone providing a continuous pathway for lithium ion transport in composite electrolytes. The porous microstructure of the fabricated thin films is confirmed via scanning electron microscopy. Ionic conductivity of the pristine films is determined via electrochemical impedance spectroscopy. We show that annealing times have a significant impact on the ionic conductivity of the films. The subsequent polymer infiltration of the porous garnet films shows a maximum ionic conductivity of 5.3 × 10−7 S cm−1 at 298 K, which is six orders of magnitude higher than the pristine porous garnet film.


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