scholarly journals Lithium-Rich Cobalt-Free Manganese-Based Layered Cathode Materials for Li-Ion Batteries: Suppressing the Voltage Fading

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3487
Author(s):  
Ashraf Abdel-Ghany ◽  
Ahmed M. Hashem ◽  
Alain Mauger ◽  
Christian M. Julien
Keyword(s):  
Layered Structure ◽  
Performance Enhancement ◽  
Electrochemical Impedance ◽  
Discharge Process ◽  
High Porosity ◽  
Li Ion Batteries ◽  
Hydrothermal Route ◽  
Li Ion ◽  
Fading Rate ◽  
Charge Discharge

Lithium-rich layered oxides are recognized as promising materials for Li-ion batteries, owing to higher capacity than the currently available commercialized cathode, for their lower cost. However, their voltage decay and cycling instability during the charge/discharge process are problems that need to be solved before their practical application can be envisioned. These problems are mainly associated with a phase transition of the surface layer from the layered structure to the spinel structure. In this paper, we report the AlF3-coating of the Li-rich Co-free layered Li1.2Ni0.2Mn0.6O2 (LLNMO) oxide as an effective strategy to solve these problems. The samples were synthesized via the hydrothermal route that insures a very good crystallization in the layered structure, probed by XRD, energy-dispersive X-ray (EDX) spectroscopy, and Raman spectroscopy. The hydrothermally synthesized samples before and after AlF3 coating are well crystallized in the layered structure with particle sizes of about 180 nm (crystallites of ~65 nm), with high porosity (pore size 5 nm) determined by Brunauer–Emmett–Teller (BET) specific surface area method. Subsequent improvements in discharge capacity are obtained with a ~5-nm thick coating layer. AlF3-coated Li1.2Ni0.2Mn0.6O2 delivers a capacity of 248 mAh g−1 stable over the 100 cycles, and it exhibits a voltage fading rate of 1.40 mV per cycle. According to the analysis from galvanostatic charge-discharge and electrochemical impedance spectroscopy, the electrochemical performance enhancement is discussed and compared with literature data. Post-mortem analysis confirms that the AlF3 coating is a very efficient surface modification to improve the stability of the layered phase of the Li-rich material, at the origin of the significant improvement of the electrochemical properties.

scholarly journals Quasi-3D modeling of Li-ion batteries based on single 2D image

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Yoichi Takagishi ◽  
Takumi Yamanaka ◽  
Tatsuya Yamaue
Keyword(s):  
3D Model ◽  
Ion Beam ◽  
Active Material ◽  
3D Structure ◽  
Porous Electrodes ◽  
Ion Concentration ◽  
Discharge Process ◽  
Li Ion Batteries ◽  
Li Ion ◽  
Charge Discharge

Abstract Electrochemical physics-based simulations of Li-ion batteries using a mesoscale 3D structure of porous electrodes are one of the most effective approaches for evaluating the local Li concentration in active materials and the Li-ion concentration in electrolytes. However, this approach requires considerable computational resources compared with a simple 2D or 1D homogeneous simulation. In this work, we developed an advanced electrochemical physics-based simulation method for Li-ion batteries that enabled a quasi-3D simulation of charge/discharge using only a single 2D slice image. The governing equations were based on typical theories of electrochemical reactions and ion transport. From referencing the 2D plane, the model was able to simulate both the Li concentration in the active material and the Li-ion concentration in the electrolyte for their subsequent consideration in a virtual 3D structure. To confirm the validity of our proposed model, a full 3D discharge simulation with randomly packed active material particles was performed and compared with the results of the quasi-3D model and a simple-2D model. Results indicated that the quasi-3D model properly reproduced the sliced Li and Li-ion concentrations simulated by the full 3D model in the charge/discharge process, whereas the simple-2D simulation partially overestimated or underestimated these concentrations. In addition, the quasi-3D model made it possible to dramatically decrease the computation time compared to the full-3D model. Finally, we applied the model to an actual scanning electron microscopy equipped with a focused ion beam (FIB-SEM) image of a positive electrode. Graphic abstract

scholarly journals Quasi-3D Modeling of Li-ion Batteries Based on Single 2D Image

2021 ◽  
Author(s):  
Yoichi Takagishi ◽  
Tatsuya Yamaue ◽  
Takumi Yamanaka
Keyword(s):  
3D Model ◽  
Ion Beam ◽  
Active Material ◽  
3D Structure ◽  
Simulation Method ◽  
Ion Concentration ◽  
Discharge Process ◽  
Li Ion Batteries ◽  
Li Ion ◽  
Charge Discharge

In this work, we developed an advanced electrochemical physics-based simulation method for Li-ion batteries that enabled a quasi-3D simulation of charge/discharge using only a single 2D slice image. The governing equations are based on typical theories of electrochemical reactions and ion transport. From referencing the 2D plane, the model was able to simulate both the Li concentration in the active material and the Li-ion concentration in the electrolyte for their subsequent consideration in a virtual 3D structure. To confirm the validity of our proposed model, a full 3D discharge simulation with randomly packed active material particles was performed and compared with the results of the quasi-3D model and a simple-2D model. Results indicated that the quasi-3D model properly reproduced the sliced Li and Li-ion concentrations simulated by the full 3D model in the charge/discharge process, whereas the simple-2D simulation partially overestimated or underestimated these concentrations. Finally, we applied the model to an actual Scanning Electron Microscopy equipped with a Focused Ion Beam (FIB-SEM) image of a positive electrode.

scholarly journals Electrochemical Performance of Graphene blended NiFe2O4 Composite

2019 ◽  
Vol 9 (2S2) ◽  
pp. 245-248
Keyword(s):  
Nickel Ferrite ◽  
Electrochemical Impedance ◽  
Reversible Capacity ◽  
Li Ion Batteries ◽  
Visible Spectroscopy ◽  
Li Ion ◽  
Activating Agent ◽  
Uv Visible ◽  
Cyclic Voltammeter ◽  
Charge Discharge

Graphene was blended with Nickel ferrite in the form of nanocomposite, which was prepared by solid state synthesis using tartaric acid as an activating agent. The nanocomposite was characterized by XRD, SEM, FTIR and UV Visible spectroscopy. Unlike the other composite materials, the Graphene – Nickel ferrite composite (GNFC) showed high specific reversible capacity, which has been studied by the cyclic voltammeter. The electrochemical impedance studies of GNFC proved that such material can be useful for the anode material of the Li-ion batteries. The fast charge-discharge property may be due to the heteroarchitechure of the GNFC..

scholarly journals Quasi-3D Modeling of Li-ion Batteries Based on Single 2D Image

2021 ◽  
Author(s):  
Yoichi Takagishi ◽  
Tatsuya Yamaue ◽  
Takumi Yamanaka
Keyword(s):  
3D Model ◽  
Ion Beam ◽  
Active Material ◽  
3D Structure ◽  
Simulation Method ◽  
Ion Concentration ◽  
Discharge Process ◽  
Li Ion Batteries ◽  
Li Ion ◽  
Charge Discharge

In this work, we developed an advanced electrochemical physics-based simulation method for Li-ion batteries that enabled a quasi-3D simulation of charge/discharge using only a single 2D slice image. The governing equations are based on typical theories of electrochemical reactions and ion transport. From referencing the 2D plane, the model was able to simulate both the Li concentration in the active material and the Li-ion concentration in the electrolyte for their subsequent consideration in a virtual 3D structure. To confirm the validity of our proposed model, a full 3D discharge simulation with randomly packed active material particles was performed and compared with the results of the quasi-3D model and a simple-2D model. Results indicated that the quasi-3D model properly reproduced the sliced Li and Li-ion concentrations simulated by the full 3D model in the charge/discharge process, whereas the simple-2D simulation partially overestimated or underestimated these concentrations. Finally, we applied the model to an actual Scanning Electron Microscopy equipped with a Focused Ion Beam (FIB-SEM) image of a positive electrode.

scholarly journals Analysis of processes in Li-ion batteries by time-of-flight neutron diffraction

2014 ◽  
Vol 70 (a1) ◽  
pp. C359-C359
Author(s):  
Ivan Bobrikov ◽  
Anatoly Balagurov ◽  
Chih-Wei Hu ◽  
Chih-Hao Lee ◽  
Sangaa Deleg
Keyword(s):  
Neutron Diffraction ◽  
Time Of Flight ◽  
Ex Situ ◽  
Discharge Process ◽  
Li Ion Batteries ◽  
Pulsed Reactor ◽  
In Situ Experiments ◽  
Li Ion ◽  
Charge Discharge

Ex-situ and in-situ neutron diffraction experiments were performed at HRFD time-of-flight (TOF) diffractometer (IBR-2 long-pulsed reactor, JINR) to characterize the entire battery system based on LiFePO4 and V-added LiFePO4 electrodes during electrochemical cycling and to find additional information about crystal structure of electrodes. Another purpose of this work was checking possibilities for in-situ experiments with real Li-ion batteries at the IBR-2 pulsed reactor. An important advantage of TOF method is the possibility to work at the fixed geometry of the experiment, which allows selecting the optimal battery orientation relative to the directions of the incident and scattered neutron beams and, thus, to minimize the difficulties associated with complex internal structure of the battery. It was shown that charge/discharge process of Li-based real Li-ion battery can be effectively studied by TOF technique at the IBR-2 pulsed reactor. Three full charge/discharge cycles were realized at room temperature (~170C) with slow rate. The step-like appearance of several LiCn phases was observed and the volume fractions of LiFePO4 and FePO4 structural phases at different states of charge were determined. The analysis of changes in cathode material microstructure when doped with vanadium showed a significant increase in the density of defects, which correlates with better electrochemical properties of V-added LiFePO4 compared to pure LiFePO4.

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