scholarly journals Clarifying the relationship between redox activity and electrochemical stability in solid electrolytes

2020 ◽  
Vol 19 (4) ◽  
pp. 428-435 ◽  
Author(s):  
Tammo K. Schwietert ◽  
Violetta A. Arszelewska ◽  
Chao Wang ◽  
Chuang Yu ◽  
Alexandros Vasileiadis ◽  
...  
Keyword(s):  
Solid Electrolytes ◽  
Electrochemical Stability ◽  
Redox Activity ◽  
The Relationship

Experimental Assessment of the Practical Oxidative Stability of Lithium Thiophosphate Solid Electrolytes

2019 ◽  
Author(s):  
Georg Dewald ◽  
Saneyuki Ohno ◽  
Marvin Kraft ◽  
Raimund Koerver ◽  
Paul Till ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Oxidative Stability ◽  
Photoelectron Spectroscopy ◽  
Solid Electrolytes ◽  
Stability Limit ◽  
Lithium Ion ◽  
High Energy ◽  
Redox Activity ◽  
Solid State Batteries

<p>All-solid-state batteries are often expected to replace conventional lithium-ion batteries in the future. However, the practical electrochemical and cycling stability of the best-conducting solid electrolytes, i.e. lithium thiophosphates, are still critical issues that prevent long-term stable high-energy cells. In this study, we use <i>stepwise</i><i>cyclic voltammetry </i>to obtain information on the practical oxidative stability limit of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>, a Li<sub>2</sub>S‑P<sub>2</sub>S<sub>5</sub>glass, as well as the argyrodite Li<sub>6</sub>PS<sub>5</sub>Cl solid electrolytes. We employ indium metal and carbon black as the counter and working electrode, respectively, the latter to increase the interfacial contact area to the electrolyte as compared to the commonly used planar steel electrodes. Using a stepwise increase in the reversal potentials, the onset potential at 25 °C of oxidative decomposition at the electrode-electrolyte interface is identified. X‑ray photoelectron spectroscopy is used to investigate the oxidation of sulfur(-II) in the thiophosphate polyanions to sulfur(0) as the dominant redox process in all electrolytes tested. Our results suggest that after the formation of these decomposition products, significant redox behavior is observed. This explains previously reported redox activity of thiophosphate solid electrolytes, which contributes to the overall cell performance in solid-state batteries. The <i>stepwise cyclic voltammetry</i>approach presented here shows that the practical oxidative stability at 25 °C of thiophosphate solid electrolytes against carbon is kinetically higher than predicted by thermodynamic calculations. The method serves as an efficient guideline for the determination of practical, kinetic stability limits of solid electrolytes. </p>

Experimental Assessment of the Practical Oxidative Stability of Lithium Thiophosphate Solid Electrolytes

2019 ◽  
Author(s):  
Georg Dewald ◽  
Saneyuki Ohno ◽  
Marvin Kraft ◽  
Raimund Koerver ◽  
Paul Till ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Oxidative Stability ◽  
Photoelectron Spectroscopy ◽  
Solid Electrolytes ◽  
Stability Limit ◽  
Lithium Ion ◽  
High Energy ◽  
Redox Activity ◽  
Solid State Batteries

<p>All-solid-state batteries are often expected to replace conventional lithium-ion batteries in the future. However, the practical electrochemical and cycling stability of the best-conducting solid electrolytes, i.e. lithium thiophosphates, are still critical issues that prevent long-term stable high-energy cells. In this study, we use <i>stepwise</i><i>cyclic voltammetry </i>to obtain information on the practical oxidative stability limit of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>, a Li<sub>2</sub>S‑P<sub>2</sub>S<sub>5</sub>glass, as well as the argyrodite Li<sub>6</sub>PS<sub>5</sub>Cl solid electrolytes. We employ indium metal and carbon black as the counter and working electrode, respectively, the latter to increase the interfacial contact area to the electrolyte as compared to the commonly used planar steel electrodes. Using a stepwise increase in the reversal potentials, the onset potential at 25 °C of oxidative decomposition at the electrode-electrolyte interface is identified. X‑ray photoelectron spectroscopy is used to investigate the oxidation of sulfur(-II) in the thiophosphate polyanions to sulfur(0) as the dominant redox process in all electrolytes tested. Our results suggest that after the formation of these decomposition products, significant redox behavior is observed. This explains previously reported redox activity of thiophosphate solid electrolytes, which contributes to the overall cell performance in solid-state batteries. The <i>stepwise cyclic voltammetry</i>approach presented here shows that the practical oxidative stability at 25 °C of thiophosphate solid electrolytes against carbon is kinetically higher than predicted by thermodynamic calculations. The method serves as an efficient guideline for the determination of practical, kinetic stability limits of solid electrolytes. </p>

Electrochemical Stability and Performance of Li2OHCl Substituted by F or Br as Solid-State Electrolyte

2020 ◽  
Vol 18 (2) ◽  
Author(s):  
Yong-Seok Lee ◽  
Su-Yeon Jung ◽  
Kwang-Sun Ryu
Keyword(s):  
Solid State ◽  
Solid Electrolyte ◽  
Solid Electrolytes ◽  
Interstitial Site ◽  
Electrochemical Stability ◽  
The Other ◽  
Chemical Bonds ◽  
Solid State Electrolyte ◽  
And Performance

Abstract Li2(OH)0.9F0.1Cl, Li2(OH)0.9Br0.1Cl, and Li2OHCl0.8Br0.2 solid electrolytes were synthesized and compared with Li2OHCl to analyze the exact improvement mechanism for Li+ conductivity and electrochemical stability of Li2OHX-type solid electrolyte. The substituted materials exhibit improved electrochemical stability and Li+ conductivity Li2OHCl. Among these materials, Li(OH)0.9F0.1Cl has improved Li+ conductivity due to a reduction of the OH– concentration and the conductivity of Li2OHCl0.8Br0.2 was also increased compared with Li2OHCl due to the large interstitial site. In the case of Li2(OH)0.9Br0.1Cl, it had the highest Li+ conductivity and good Li+ migration by both effects because of a larger interstitial site and low OH− concentration. Furthermore, the electrochemical stability of four materials was compared due to the different structural stabilities and strengths of binary chemical bonds such as Li–X, H–X, and O–X. Comparing the Li+ conductivity of Li2(OH)0.9F0.1Cl and Li2OHCl0.8Br0.2, the Li+ conductivity is influenced by the OH− concentration unlike the other mechanisms.

scholarly journals Exploring the relationship between solvent-assisted ball milling, particle size, and sintering temperature in garnet-type solid electrolytes

2021 ◽  
Vol 484 ◽  
pp. 229252
Author(s):  
Marissa Wood ◽  
Xiaosi Gao ◽  
Rongpei Shi ◽  
Tae Wook Heo ◽  
Jose Ali Espitia ◽  
...  
Keyword(s):  
Particle Size ◽  
Ball Milling ◽  
Solid Electrolytes ◽  
Sintering Temperature ◽  
The Relationship

scholarly journals Electrochemical Stability of Li10 GeP2 S12 and Li7 La3 Zr2 O12 Solid Electrolytes

2016 ◽  
Vol 6 (8) ◽  
pp. 1501590 ◽  
Author(s):  
Fudong Han ◽  
Yizhou Zhu ◽  
Xingfeng He ◽  
Yifei Mo ◽  
Chunsheng Wang
Keyword(s):  
Solid Electrolytes ◽  
Electrochemical Stability

Enhanced Ionic Conductivity in Ce0.8Gd0.2O2-δ Nanofiber: Effect of the Crystallite Size

2018 ◽  
Vol 281 ◽  
pp. 761-766 ◽  
Author(s):  
Meng Fei Zhang ◽  
Tian Jun Li ◽  
Xiao Hui Zhao ◽  
Hua Jian Zhou ◽  
Wei Pan
Keyword(s):  
Crystallite Size ◽  
Solid Electrolytes ◽  
Average Crystallite Size ◽  
Ionic Transport ◽  
Oxygen Sensors ◽  
Oxide Ion Conductivity ◽  
Crystallite Sizes ◽  
Electrochemical Devices ◽  
The Relationship ◽  
Oxide Ion

The relationship between the microstructure and the conductivity of nanocrystallized oxygen ionic electrolytes has been received great interest since it provides guidelines for designing electrolytes with high performances which might find applications in fuel cells and oxygen sensors. Here, we present a strategy for controlling the calcination temperature to tune the crystallite size and ionic transport properties of solid electrolyte. Different crystallite sizes of Ce0.8Gd0.2O2-δ (CGO) nanofiber electrolytes were prepared. As the average crystallite size decreased from 27 nm to 8 nm, the conductivity of the nanofibers increased by more than five times. An exceptionally high oxide ion conductivity of 0.023 S∙cm-1 for the nanofibers was observed at 550°C. These insights into the effect of the crystallite size on the structure and the conductivity allow a better control of the electrical properties of solid electrolytes, which might foster their applications in electrochemical devices operable at lower temperatures.

scholarly journals Effect of Sintering Process on Ionic Conductivity of Li7-xLa3Zr2-xNbxO12 (x = 0, 0.2, 0.4, 0.6) Solid Electrolytes

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1671
Author(s):  
Lei Ni ◽  
Zhigang Wu ◽  
Chuyi Zhang
Keyword(s):  
Ionic Conductivity ◽  
Solid Electrolytes ◽  
High Performance ◽  
Room Temperature ◽  
Process Conditions ◽  
Sintering Process ◽  
Preparation Time ◽  
Conventional Solid State Reaction ◽  
Good Crystallinity ◽  
The Relationship

Garnet-type Li7La3Zr2O12 (LLZO) is considered as a promising solid electrolyte. Nb-doped LLZO ceramics exhibit significantly improved ion conductivity. However, how to prepare the Nb-doped LLZO ceramics in a simple and economical way, meanwhile to investigate the relationship between process conditions and properties in Li7-xLa3Zr2-xNbxO12 ceramics, is particularly important. In this study, Li7-xLa3Zr2-xNbxO12 (LLZNxO, x = 0, 0.2, 0.4, 0.6) ceramics were prepared by conventional solid-state reaction. The effect of sintering process on the structure, microstructure, and ionic conductivity of LLZNxO (x = 0, 0.2, 0.4, 0.6) ceramics was investigated. Due to the more contractive Nb-O bonds in LLZNxO ceramics, the cubic structures are much easier to form and stabilize, which could induce the decreased preparation time. High-performance garnet LLZNxO ceramics can be obtained by optimizing the sintering process with lower calcining temperature and shorter holding time. The garnet samples with x = 0.4 calcined at 850 °C for 10 h and sintered at 1250 °C for 4 h exhibit the highest ionic conductivity of 3.86 × 10−4 S·cm−1 at room temperature and an activation energy of 0.32 eV, which can be correlated to the highest relative density of 96.1%, and good crystallinity of the grains.

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