Triple molybdates K3–x Na1+x M 4(MoO4)6 (M = Ni, Mg, Co) and K3+x Li1–x Mg4(MoO4)6 isotypic with II-Na3Fe2(AsO4)3 and yurmarinite: synthesis, potassium disorder, crystal chemistry and ionic conductivity

2020 ◽  
Vol 76 (5) ◽  
pp. 913-925
Author(s):  
Oksana A. Gulyaeva ◽  
Zoya A. Solodovnikova ◽  
Sergey F. Solodovnikov ◽  
Evgeniya S. Zolotova ◽  
Yuliya G. Mateyshina ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Crystal Chemistry ◽  
Three Dimensional ◽  
Compound K ◽  
Lithium Ions ◽  
Ion Conductor ◽  
Ternary Molybdate ◽  
Bond Valence Sum ◽  
Structural Formulae ◽  
Triple Molybdates

The triple molybdates K3–x Na1+x M 4(MoO4)6 (M = Ni, Mg, Co) and K3+x Li1–x Mg4(MoO4)6 were found upon studying the corresponding ternary molybdate systems, and their structures, thermal stability and electrical conductiviplusmnty were investigated. The compounds crystallize in the space group R 3 c and are isostructural with the sodium-ion conductor II-Na3Fe2(AsO4)3 and yurmarinite, Na7(Fe3+, Mg, Cu)4(AsO4)6; their basic structural units are flat polyhedral clusters of the central M1O6 octahedron sharing edges with three surrounding M2O6 octahedra, which combine with single NaO6 octahedra and bridging MoO4 tetrahedra to form open three-dimensional (3D) frameworks where the cavities are partially occupied by disordered potassium (sodium) ions. The split alkali-ion positions in K3–x Na1+x M 4(MoO4)6 (M = Ni, Mg, Co) give their structural formulae as [(K,Na)0.5□0.5)]6(Na)[M1][M2]3(MoO4)6, whereas the lithium-containing compound (K0.5□0.5)6(Mg0.89K0.11)(Li0.89Mg0.11)Mg3(MoO4)6 shows an unexpected (Mg, K) isomorphism, which is similar to (Mn, K) and (Co, K) substitutions in isostructural K3+x Li1–x M 4(MoO4)6 (M = Mn, Co). The crystal chemistry of the title compounds and related arsenates, phosphates and molybdates was considered, and the connections of the cationic distributions with potential 3D ionic conductivity were shown by means of calculating the bond valence sum (BVS) maps for the Na+, Li+ and K+ ions. Electrical conductivity measurements gave relatively low values for the triple molybdates [σ = 4.8 × 10−6 S cm−1 at 390°C for K3NaCo4(MoO4)6 and 5 × 10−7 S cm−1 at 400°C for K3LiMg4(MoO4)6] compared with II-Na3Fe2(AsO4)3 (σ = 8.3 × 10−4 S cm−1 at 300°C). This may be explained by a low concentration of sodium or lithium ions and the blocking of their transport by large potassium ions.

An arsenate with the α-CrPO4 structure type, NaCa1–x Ni3–2x Al2x (AsO4)3 (x = 0.23): crystal structure, charge-distribution and bond-valence-sum analyses

2017 ◽  
Vol 73 (11) ◽  
pp. 896-904 ◽  
Author(s):  
Ridha Ben Smail ◽  
Mohamed Faouzi Zid
Keyword(s):  
Crystal Structure ◽  
Charge Distribution ◽  
Structural Model ◽  
Ionic Conduction ◽  
Three Dimensional ◽  
Structure Type ◽  
Bond Valence ◽  
Ion Conductor ◽  
X Ray ◽  
Bond Valence Sum

Since the discovery of electrochemically active LiFePO4, materials with tunnel and layered structures built up of transition metals and polyanions have become the subject of much research. A new quaternary arsenate, sodium calcium trinickel aluminium triarsenate, NaCa1–x Ni3–2x Al2x (AsO4)3 (x = 0.23), was synthesized using the flux method in air at 1023 K and its crystal structure was determined from single-crystal X-ray diffraction (XRD) data. This material was also characterized by qualitative energy-dispersive X-ray spectroscopy (EDS) analysis and IR spectroscopy. The crystal structure belongs to the α-CrPO4 type with the space group Imma. The structure is described as a three-dimensional framework built up of corner-edge-sharing NiO6, (Ni,Al)O6 and AsO4 polyhedra, with channels running along the [100] and [010] directions, in which the sodium and calcium cations are located. The proposed structural model has been validated by bond-valence-sum (BVS) and charge-distribution (CHARDI) tools. The sodium ionic conduction pathways in the anionic framework were investigated by means of the bond-valence site energy (BVSE) model, which predicted that the studied material will probably be a very poor Na+ ion conductor (bond-valence activation energy ∼7 eV).

Under Pressure: Mechanochemical Effects on Structure and Ion Conduction in the Sodium-Ion Solid Electrolyte Na3PS4

2020 ◽  
Author(s):  
Theodosios Famprikis ◽  
O. Ulas Kudu ◽  
James Dawson ◽  
Pieremanuele Canepa ◽  
François Fauth ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Mechanochemical Synthesis ◽  
Activation Volume ◽  
External Pressure ◽  
Sodium Ion ◽  
Variable Pressure ◽  
Ion Conductor ◽  
Ceramic Synthesis ◽  
Solid State Batteries ◽  
Fast Ion

<div> <p>Fast-ion conductors are critical to the development of solid-state batteries. The effects of mechanochemical synthesis that lead to increased ionic conductivity in an archetypical sodium-ion conductor Na<sub>3</sub>PS<sub>4</sub> are not fully understood. We present here a comprehensive analysis based on diffraction (Bragg, pair distribution function), spectroscopy (impedance, Raman, NMR, INS) and <i>ab-initio</i> simulations aimed at elucidating the synthesis-property relationships in Na<sub>3</sub>PS<sub>4</sub>. We consolidate previously reported interpretations about the local structure of ball-milled samples, underlining the sodium disorder and showing that a local tetragonal framework more accurately describes the structure than the originally proposed cubic one. Through variable-pressure impedance spectroscopy measurements, we report for the first time the activation volume for Na<sup>+</sup> migration in Na<sub>3</sub>PS<sub>4</sub>, which is ~30% higher for the ball-milled samples. Moreover, we show that the effect of ball-milling on increasing the ionic conductivity of Na<sub>3</sub>PS<sub>4</sub> to ~10<sup>-4</sup> S/cm can be reproduced by applying external pressure on a sample from conventional high temperature ceramic synthesis. We conclude that the key effects of mechanochemical synthesis on the properties of solid electrolytes can be analyzed and understood in terms of pressure, strain and activation volume.</p> </div>

scholarly journals Na3Co2(As0.52P0.48)O4(As0.95P0.05)2O7

2013 ◽  
Vol 69 (12) ◽  
pp. i85-i86 ◽  
Author(s):  
Youssef Ben Smida ◽  
Abderrahmen Guesmi ◽  
Mohamed Faouzi Zid ◽  
Ahmed Driss
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Title Compound ◽  
General Position ◽  
Structural Model ◽  
Three Dimensional ◽  
The Other ◽  
Coordination Polyhedra ◽  
Bond Valence Sum ◽  
Full Occupancy

The title compound, trisodium dicobalt(II) (arsenate/phosphate) (diarsenate/diphosphate), was prepared by a solid-state reaction. It is isostructural with Na3Co2AsO4As2O7. The framework shows the presence of CoX22O12(X2 is statistically disordered with As0.95P0.05) units formed by sharing corners between Co1O6octahedra andX22O7groups. These units form layers perpendicular to [010]. Co2O6octahedra andX1O4(X1 = As0.54P0.46) tetrahedra form Co2X1O8chains parallel to [001]. Cohesion between layers and chains is ensured by theX22O7groups, giving rise to a three-dimensional framework with broad tunnels, running along thea- andc-axis directions, in which the Na+ions reside. The two Co2+cations, theX1 site and three of the seven O atoms lie on special positions, with site symmetries 2 andmfor the Co,mfor theX1, and 2 andm(× 2) for the O sites. One of two Na atoms is disordered over three special positions [occupancy ratios 0.877 (10):0.110 (13):0.066 (9)] and the other is in a general position with full occupancy. A comparison between structures such as K2CdP2O7, α-NaTiP2O7and K2MoO2P2O7is made. The proposed structural model is supported by charge-distribution (CHARDI) analysis and bond-valence-sum (BVS) calculations. The distortion of the coordination polyhedra is analyzed by means of the effective coordination number.

3DBVSMAPPER: a program for automatically generating bond-valence sum landscapes

2012 ◽  
Vol 45 (5) ◽  
pp. 1054-1056 ◽  
Author(s):  
Matthew Sale ◽  
Maxim Avdeev
Keyword(s):  
Computer Program ◽  
Three Dimensional ◽  
Bond Valence ◽  
Spatial Distributions ◽  
Energy Landscapes ◽  
Bond Valence Sum ◽  
Scripting Language ◽  
Materials Studio ◽  
User Intervention ◽  
Minimal User Intervention

A computer program,3DBVSMAPPER, was developed to generate bond-valence sum maps and bond-valence energy landscapes with minimal user intervention. The program is designed to calculate the spatial distributions of bond-valence values on three-dimensional grids, and to identify infinitely connected isosurfaces in these spatial distributions for a given bond-valence mismatch or energy threshold and extract their volume and surface area characteristics. It is implemented in the Perl scripting language embedded in AccelrysMaterials Studioand has the capacity to process automatically an unlimited number of materials using crystallographic information files as input.

scholarly journals PEO Infiltration of Porous Garnet-Type Lithium-Conducting Solid Electrolyte Thin Films

Ceramics ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 421-436
Author(s):  
Aamir Iqbal Waidha ◽  
Vanita Vanita ◽  
Oliver Clemens
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Ionic Conductivity ◽  
Electrochemical Impedance ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Interfacial Resistance ◽  
Composite Electrolytes ◽  
Ion Conducting ◽  
Polymer Infiltration

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.

NASICON-structured Na ion conductor for next generation energy storage

2021 ◽  
pp. 2130005
Author(s):  
Qing Huang ◽  
Gongxuan Chen ◽  
Ping Zheng ◽  
Wei Li ◽  
Tian Wu
Keyword(s):  
Energy Storage ◽  
Solid State ◽  
Ionic Conductivity ◽  
Solid Electrolytes ◽  
Electrical Energy ◽  
Next Generation ◽  
Ion Conductor ◽  
Electrical Energy Storage ◽  
Composition Properties ◽  
Stable Structures

The demand for electrical energy storage (EES) is ever increasing in order to develop better batteries. NASICON-structured Na ion conductor represents a class of solid electrolytes, which is of great interest due to its superior ionic conductivity and stable structures. They are widely employed in all-solid-state ion batteries, all-solid-state air batteries, and hybrid batteries. In this review, their structure, composition, properties, and applications for next generation energy storage are reviewed.

High-Pressure Synthesis, Crystal Chemistry, and Ionic Conductivity of a Structural Polymorph of Li3BP2O8

2018 ◽  
Vol 57 (24) ◽  
pp. 15048-15050
Author(s):  
Eiichi Hirose ◽  
Kunimitsu Kataoka ◽  
Hiroshi Nagata ◽  
Junji Akimoto ◽  
Takuya Sasaki ◽  
...  
Keyword(s):  
High Pressure ◽  
Ionic Conductivity ◽  
Crystal Chemistry ◽  
High Pressure Synthesis ◽  
Pressure Synthesis

scholarly journals Dipotassium tetrahydroxidopentaoxidotetraborate monohydrate

IUCrData ◽  
2019 ◽  
Vol 4 (1) ◽  
Author(s):  
M. K. Dhatchaiyini ◽  
M. NizamMohideen ◽  
G. Rajasekar ◽  
A. Bhaskaran
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Coordination Number ◽  
Title Compound ◽  
Three Dimensional ◽  
Compound K ◽  
Bond Lengths ◽  
Dimensional Network

In the tetraborate anion of the title compound, K2[B4O5(OH)4]·H2O, the bridging B—O bond lengths of the tetrahedral BO4 and the trigonal-planar BO3 units are slightly longer than the corresponding terminal B—OH bond lengths. The crystal structure is stabilized by intermolecular O—H...O, O—H...Owater and Owater—H...O hydrogen bonds, generating a three-dimensional network. The two potassium cations both show a coordination number of 9.

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