scholarly journals Classification of Spatio-temporal Patterns in Charging and Discharging of Li-ion Batteries

2021 ◽  
Author(s):  
Moshe Sheintuch ◽  
Olga Nekhamkina
Keyword(s):  
Potential Gradient ◽  
Li Ion Batteries ◽  
Two Phase ◽  
Variable Model ◽  
Current Function ◽  
Li Ion ◽  
Spatio Temporal ◽  
Gradient Effects ◽  
Galvanostatic Conditions

We classify the dynamic patterns that emerge in charging or discharging of Li-ion batteries, under galvanostatic conditions, using simulations of the two-phase 1D porous model. This work examines the effect of exchange current function, R0(X), which expresses the nature of kinetics and extends our previous study limited to R0=1 for which the same pattern emerges, whether homogeneous or step-wise process made of multiple symmetry breaking events. With the commonly-used asymmetric R0(X) the emerging pattern may be one of the two above or fronts that follow single SB event and lithiation/delithiation behaviors are different. These effects are clear when parameters are uniform; non-uniformity leads to noise that mask the behavior. The full 4-variable model exhibits SB, even in absence of noise, since the liquid potential gradient ( ) works like a perturbation. Similarity between noise and gradient effects allows us to derive approximations to full model behavior, and study various effects.

scholarly journals Study on the structural phase transitions in NaSICON-type compounds using Ag3Sc2(PO4)3 as a model system

2020 ◽  
Vol 77 (1) ◽  
Author(s):  
Günther J. Redhammer ◽  
Gerold Tippelt ◽  
Quirin Stahl ◽  
Artur Benisek ◽  
Daniel Rettenwander
Keyword(s):  
Phase Transitions ◽  
Structural Phase ◽  
Ionic Conductivities ◽  
Phase Behaviour ◽  
Li Ion Batteries ◽  
Two Phase ◽  
Structured Materials ◽  
Β Phase ◽  
Nasicon Type ◽  
Li Ion

NaSICON (Na Super-Ionic CONducting) structured materials are among the most promising solid electrolytes for Li-ion batteries and `beyond Li-ion' batteries (e.g. Na and K) due to their superior ionic conductivities. Although this material has been well known for decades, its exact phase behaviour is still poorly understood. Herein, a starting material of Na3Sc2(PO4)3 single crystals is used, grown by flux methodology, where Na is subsequently chemically replaced by Ag, in order to take advantage of the higher scattering contrast of Ag. It is found that the NaSICON-type compound shows two phase transitions from a low-temperature monoclinic α-phase to a monoclinic β-phase at about 180 K and to a rhombohedral γ-phase at about 290 K. The framework of [Sc2(PO4)3]3− is rigid and does not change significantly with temperature and change of symmetry. The main driving force for the phase transitions is related to order–disorder phenomena of the conducting cations. The sensitivity of the phase behaviour on the ordering of these ions suggests that small compositional changes can have a great impact on the phase behaviour and, hence, on the ionic conductivity of NaSICON-structured materials.

Porous Al/Al2O3 two-phase nanonetwork to improve electrochemical properties of porous C/SiO2 as anode for Li-ion batteries

2019 ◽  
Vol 300 ◽  
pp. 470-481 ◽  
Author(s):  
Jinlong Cui ◽  
Jiachao Yang ◽  
Jianzong Man ◽  
Shaohui Li ◽  
Jinpeng Yin ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Li Ion Batteries ◽  
Two Phase ◽  
Li Ion

scholarly journals Pushing the limit of layered transition metal oxide cathodes for high-energy density rechargeable Li ion batteries

2018 ◽  
Vol 11 (5) ◽  
pp. 1271-1279 ◽  
Author(s):  
U.-H. Kim ◽  
D.-W. Jun ◽  
K.-J. Park ◽  
Q. Zhang ◽  
P. Kaghazchi ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Energy ◽  
High Energy Density ◽  
Li Ion Batteries ◽  
Two Phase ◽  
Oxide Cathodes ◽  
Li Ion ◽  
Layered Transition Metal ◽  
Thermal Stability Of ◽  
W Doping

W-doping produced the two-phase (Fm3̄m and R3̄m) structure which improved the cycling and thermal stability of the Ni-rich layered cathodes.

scholarly journals Operando Monitoring the Insulator-Metal Transition of LiCoO2

2021 ◽  
Author(s):  
Eibar Flores ◽  
Nataliia Mozhzhukhina ◽  
Ulrich Aschauer ◽  
Erik Berg
Keyword(s):  
Phase Transition ◽  
Solid Solution ◽  
Raman Spectroscopy ◽  
Dft Calculations ◽  
Active Material ◽  
Rate Capability ◽  
Li Ion Batteries ◽  
Two Phase ◽  
Insulator Metal Transition ◽  
Li Ion

LiCoO<sub>2</sub> (LCO) is one of the most-widely used cathode active materials for Li-ion batteries. Even though the material undergoes an electronic two-phase transition upon Li-ion cell charging, LCO exhibits competitive performance in terms of rate capability. Herein the insulator-metal transition of LCO is investigated by <i>operando</i> Raman spectroscopy complemented with DFT calculations and a newly-developed sampling volume model. We confirm the presence of a Mott insulator α-phase at dilute Li-vacancy concentrations (x > 0.87) that transforms into a metallic β-phase at x < 0.75. In addition, we find that the charge-discharge intensity trends of LCO Raman-active bands exhibit a characteristic hysteresis, which, unexpectedly, narrows at higher cycling rates. When comparing these trends to a newly-developed numerical model of laser penetration into a spatially-heterogeneous particle we provide compelling evidence that the insulator-metal transition of LCO follows a two-phase route at very low cycling rates, which is suppressed in favor of a solid-solution route at rates above 10 mA/g<sub>LCO</sub> (~C/10). The observations explain why LCO exhibits competitive rate capabilities despite being observed to undergo an intuitively slow two-phase transition route: a kinetically faster solid-solution transition route becomes available when the active material is cycled at rates >C/10. <i>Operando</i> Raman spectroscopy combined with sample volume modelling and DFT calculations is shown to provide unique insights into fundamental processes governing the performance of state-of-the-art cathode materials for Li-ion batteries.

scholarly journals Two-phase interface hydrothermal synthesis of binder-free SnS2/graphene flexible paper electrodes for high-performance Li-ion batteries

RSC Advances ◽  
2019 ◽  
Vol 9 (41) ◽  
pp. 23607-23613 ◽  
Author(s):  
Hao Wen ◽  
Wenbin Kang ◽  
Xingang Liu ◽  
Wenjuan Li ◽  
Liping Zhang ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
High Performance ◽  
Hydrothermal Reaction ◽  
Phase Interface ◽  
Lithium Ion ◽  
Li Ion Batteries ◽  
Two Phase ◽  
Excellent Electrochemical Performance ◽  
Binder Free ◽  
Li Ion

Binder-free SnS2/graphene flexible paper produced from a two-phase interface hydrothermal reaction with excellent electrochemical performance for lithium-ion batteries.

scholarly journals Diffraction studies of Tavorite-based polyanionic materials for Li–ion batteries

2014 ◽  
Vol 70 (a1) ◽  
pp. C356-C356
Author(s):  
Emmanuelle Suard ◽  
Matteo Bianchini ◽  
Jean-Marcel Ateba Mba ◽  
Christian Masquelier ◽  
Laurence Croguennec
Keyword(s):  
Phase Diagram ◽  
Low Voltage ◽  
Ex Situ ◽  
Li Ion Batteries ◽  
Two Phase ◽  
Whole Process ◽  
Structural Framework ◽  
Wide Range ◽  
Li Ion ◽  
Battery Discharge

Polyanionic materials attract great interest in the field of Li-ion batteries thanks to the wide range of possible available compositions, resulting in a great amount of different properties (1). For instance, the high working potential together with a capacity of 156 mAh/g (leading to a theoretical energy density of 655 Wh/g) made Tavorite LiVPO4F a widely studied material and a suitable candidate for commercial exploitation. Here we will focus our interest on the homeotype structure of LiVPO4O. This oxy-phosphate shows the ability to exploit two redox couples, V5+/V4+ at 3.95 V vs. Li+/Li and V4+/V3+ at an average potential of 2.3 V vs. Li+/Li upon Li+ extraction and insertion, respectively (2). The two domains show marked differences both in the electrochemical signature and in the phase diagram, which is extremely rich. In particular, while the high-voltage domain shows a relatively simple two-phase transformation between LiVPO4O and ε-VPO4O, the low-voltage domain is more complicated and it shows a series of three apparent biphasic reactions while Lithium is inserted in the Tavorite structural framework. To elucidate this reaction, we performed in-situ X-Ray diffraction (Kα1), i.e. we recorded the whole process in real time during battery discharge. The end member Li2VPO4O was also isolated ex-situ and its crystal structure determined for the first time thanks to neutron diffraction measurements (3). Both the phase diagram and the different crystal structures will be discussed.

Effect of Al(OH)3 in Enhancing PbSnF4 Anode Performances for Rechargeable Lithium-Ion Battery

2015 ◽  
Vol 245 ◽  
pp. 153-158 ◽  
Author(s):  
Denis P. Opra ◽  
Anatoly B. Podgorbunsky ◽  
Sergey V. Gnedenkov ◽  
Sergey L. Sinebryukhov ◽  
Alexander A. Sokolov ◽  
...  
Keyword(s):  
Aluminum Hydroxide ◽  
Specific Capacity ◽  
Lithium Ion ◽  
High Energy ◽  
Li Ion Batteries ◽  
Two Phase ◽  
Milling Method ◽  
Energy Ball ◽  
Li Ion ◽  
Initial Capacity

Two-phase Al(OH)3–PbSnF4 composites (concentrations of aluminum hydroxide are equal to 5 wt.%, 15 wt.% and 30 wt.%) has been prepared by high-energy ball-milling method. The materials were employed as anodes in Li-ion batteries. It was established that PbSnF4-based systems yield high initial capacity of 800–1100 mAh g–1. The reversible specific capacity of Al(OH)3–PbSnF4 (aluminum hydroxide – 15 wt.%) after 10-fold charge–discharge cycling in the range of 2.5–0.005 V attains 120 mAh g–1, while the specific capacity of pure PbSnF4 is equal only to 20 mAh g–1. It has been shown that the deviation from 15 wt.% concentration of Al (OH)3 decreases cycling stability of lead fluorostannate (II).

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