Formation of Mono/Bi-Layer Iron Phosphate 2D-Sheets and Generation of LiFePO4 Nano-Crystals in Charge/Discharge Process for High Performance Li-Ion Batteries

2016 ◽  
Keyword(s):  
High Performance ◽  
Iron Phosphate ◽  
Discharge Process ◽  
Li Ion Batteries ◽  
Li Ion ◽  
Layer Iron ◽  
Charge Discharge

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 Non-stoichiometric carbon-coated LiFexPO4as cathode materials for high-performance Li-ion batteries

RSC Advances ◽  
2017 ◽  
Vol 7 (53) ◽  
pp. 33544-33551 ◽  
Author(s):  
Ying Feng ◽  
Junjie Gu ◽  
Feng Yu ◽  
Chunfu Lin ◽  
Jinli Zhang ◽  
...  
Keyword(s):  
Cathode Materials ◽  
High Performance ◽  
Lithium Iron Phosphate ◽  
Iron Phosphate ◽  
Lattice Parameters ◽  
Li Ion Batteries ◽  
Carbon Coated ◽  
Li Ion ◽  
Work First

This work first discloses the evolution of lattice parameters of the non-stoichiometric lithium iron phosphate crystals.

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 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.

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