Structural Analysis during Charge-Discharge Process of Li2FeSiO4Synthesized by Molten Carbonate Flux Method

2012 ◽  
Vol 159 (5) ◽  
pp. A525-A531 ◽  
Author(s):  
Akira Kojima ◽  
Toshikatsu Kojima ◽  
Tetsuo Sakai
Keyword(s):  
Structural Analysis ◽  
Discharge Process ◽  
Molten Carbonate ◽  
Flux Method ◽  
Carbonate Flux ◽  
Charge Discharge

scholarly journals Phase Transformation in the Charge-Discharge Process and the Structural Analysis by Synchrotron XAFS and XRD for Nickel Hydroxide Electrode

2008 ◽  
Vol 76 (11) ◽  
pp. 802-807 ◽  
Author(s):  
Masanori MORISHITA ◽  
Seijiro OCHIAI ◽  
Tadashi KAKEYA ◽  
Tetsuya OZAKI ◽  
Yoshiteru KAWABE ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Structural Analysis ◽  
Nickel Hydroxide ◽  
Discharge Process ◽  
Charge Discharge

Synthesis of Li2MnSiO4Cathode Material Using Molten Carbonate Flux Method with High Capacity and Initial Efficiency

2012 ◽  
Vol 159 (5) ◽  
pp. A532-A537 ◽  
Author(s):  
Akira Kojima ◽  
Toshikatsu Kojima ◽  
Mitsuharu Tabuchi ◽  
Tetsuo Sakai
Keyword(s):  
High Capacity ◽  
Molten Carbonate ◽  
Flux Method ◽  
Carbonate Flux

Single atom catalysts supported on N-doped graphene toward fast kinetic Li−S batteries: a theoretical study

2021 ◽  
Author(s):  
Xu Han ◽  
Zeyun Zhang ◽  
Xuefei Xu
Keyword(s):  
Theoretical Study ◽  
Single Atom ◽  
Discharge Process ◽  
Fast Kinetics ◽  
Shuttle Effect ◽  
Sufficient Stability ◽  
Doped Graphene ◽  
Fast Kinetic ◽  
Kinetics Of ◽  
Charge Discharge

To suppress the shuttle effect of lithium polysulfides and promote fast kinetics of charge−discharge process in Li−S batteries, it is essential to search promising catalysts with sufficient stability and high...

scholarly journals Two-Electron Reaction without Structural Phase Transition in Nanoporous Cathode Material

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Tomoyuki Matsuda ◽  
Yutaka Moritomo
Keyword(s):  
Phase Transition ◽  
Cathode Material ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Discharge Process ◽  
Charge Capacity ◽  
High Charge ◽  
Valence States ◽  
X Ray Absorption ◽  
Charge Discharge

We investigated the charge/discharge properties, valence states, and structural properties of a nanoporous cathode materialLixMn[Fe(CN)6]0.83·3.5H2O. The film-type electrode ofLixMn[Fe(CN)6]0.83·3.5H2Oexhibited a high charge capacity(=128 mAh g-1)and a good cyclability (87% of the initial value after 100 cycles) and is one of the promising candidates for Li-ion battery cathode. X-ray absorption spectra near the Fe and Mn K-edges revealed that the charge/discharge process is a two-electron reaction; that is,MnII–NC–FeII,MnII–NC–FeIII, andMnIII–NC–FeIII. We further found that the crystal structure remains cubic throughout the charge/discharge process. The lattice constant slightly increased during the[FeII(CN)6]4-/[FeIII(CN)6]3-oxidization reaction while decreased during theMnII/MnIIIoxidization reaction. The two-electron reaction without structural phase transition is responsible for the high charge capacity and the good cyclability.

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 Electrochemical Performance of Molybdenum Disulfide Supercapacitor Electrode in Potassium Hydroxide and Sodium Sulfate Electrolytes

2020 ◽  
Vol 8 (6) ◽  
pp. 5499-5503
Keyword(s):  
Molybdenum Disulfide ◽  
Active Material ◽  
Current Collector ◽  
Future Application ◽  
Energy Storage Materials ◽  
Discharge Process ◽  
Supercapacitor Electrode ◽  
Optical And Mechanical Properties ◽  
Interest In Research ◽  
Charge Discharge

Two-dimensional materials have attracted growing interest in research because of their specific electronic, physical, optical and mechanical properties. Molybdenum disulfide was theoretically investigated as novel energy storage materials because of its unusual physicochemical properties. This paper describes easy approach to fabricate molybdenum disulfide (MoS2 ) electrode using slurry technique on conducting substrate namely Ni foam as current collector for supercapacitor device application. This MoS2 electrode exhibits relatively good specific gravimetric capacitance, (Csp) of 11.12 to 12.38 Fg -1 at 1 mVs -1 scan rate. Moreover, galvanostatic charge-discharge displays symmetrical triangular curves which attributed to the fast charge-discharge process (in seconds). These results show that MoS2 active material can be charged and discharged reversibly between 0.2 and 1.0 V (in 6 M KOH) and between 0.3 and 1.0 V (in 0.5 M Na2SO4 ). From cyclic stability test exhibits capacitance retention of up to 83% and 64% after 1000 cycles in 6 M KOH and 0.5 M Na2SO4 , respectively. The MoS2 electrode is thus a promising material for future application of the supercapacitor.

In situ TEM visualization of single atom catalysis in solid-state Na-O2 nanobatteries

2021 ◽  
Author(s):  
Haiming Sun ◽  
Qiunan Liu ◽  
Zhiying Gao ◽  
Lin Geng ◽  
Yanshuai Li ◽  
...  
Keyword(s):  
Solid State ◽  
Catalytic Mechanism ◽  
Single Atom ◽  
In Situ Tem ◽  
Discharge Process ◽  
Catalytic Activities ◽  
Charge Discharge

Single-atom catalysts (SACs) exhibit high catalytic activities in many systems including metal-air batteries. However, the fundamental catalytic mechanism of SACs during charge/discharge process are still unclear. Herein, we report a...

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