scholarly journals Effect of the pyrolysis temperature after hydrothermal reaction on the structure of electrode material LiFexCo1􀀀xPO4 (0.1 x 0.5) and electrochemical evaluation of this material in Li-ion half-cell

Author(s):  
Quang Đại Tran ◽  
Hoang Van Nguyen ◽  
Mẫn Văn Trần ◽  
Phụng Mỹ Loan Lê

High voltage cathode LiCoPO4 has been taken great interest for high power Li-ion batteries (LIBs). Though Co enhance the cyclability, capacity of materials, Co concentration should be reduced in electrode materials due to its high cost and toxic. In this work, the solvo-thermal reaction following by pyrolysis in inert Ar was investigated to synthesize the electrode materials LiFexCo1-xPO4 (0.1 <= x <= 0.5) for LIBs. The structure of the materials after calcinated at 600 oC, 700 oC and 800 oC was analyzed by X-ray diffraction (XRD). The results indicated that the olivine structure was obtained for all Fe contents, except for x = 0.5. At the content of 0.1 and 0.5, the intensity of impurity peaks in the samples increased with the pyrolysis temperature. Meanwhile, other samples did not display the obvious change of olivine structure. Electrochemical properties of the materials were evaluated via cyclic voltammetry (CV) and Galvanostatic charging-discharging. CV curves of the samples with Fe content of 0.2x0.4 all displayed high intensity and reversible redox peak of Co3+/Co2+ locating at 4.8 V and another peak of Fe3+/Fe2+ locating at 3.5 V. As the Fe content increased, the former peaks decreased while the latter increased due to the change of active species concentrations. Unfortunately, the specific capacities obtained for Fe-substituted materials were lower than the pristine material (70 mAh/g versus 120 mAh/g) and gradually declined during cycling. The results could be due to the electrolyte decomposition in the first charging. However, the sample with x = 0.1 exhibited the best performance with discharge capacity of 70 mAh/g and 73% capacity retention obtained after 25 cycles, which was better than the sample with x = 0.2 and unsubstituted sample.

2020 ◽  
Author(s):  
Alae Eddine Lakraychi ◽  
Simon De Kreijger ◽  
Deepak Gupta ◽  
Benjamin Elias ◽  
Alexandru Vlad

<i>1,10-Phenanthroline-5,6-dione (Phendione) - based transition metal complexes are known for their use in pharmacological and catalysis applications. However, their application in electrochemical energy storage has not been investigated thus far. Herein we prove the feasibility of employing phendione - transition metal complexes for electrochemical charge storage by taking advantage of the reversible redox of both, carbonyl groups and transition metal center, contributing thus to augmented charge storage. Interestingly, the chemistry of the counter ion in the studied complexes effectively tunes the solubility and improves the cycling stability. Whereas further studies are required to limit the solubility and active species shuttle, this study explores the bottlenecks of phendione - transition metal complexes as electrode materials for solid electrode format batteries. </i>


2020 ◽  
Author(s):  
Alae Eddine Lakraychi ◽  
Simon De Kreijger ◽  
Deepak Gupta ◽  
Benjamin Elias ◽  
Alexandru Vlad

<i>1,10-Phenanthroline-5,6-dione (Phendione) - based transition metal complexes are known for their use in pharmacological and catalysis applications. However, their application in electrochemical energy storage has not been investigated thus far. Herein we prove the feasibility of employing phendione - transition metal complexes for electrochemical charge storage by taking advantage of the reversible redox of both, carbonyl groups and transition metal center, contributing thus to augmented charge storage. Interestingly, the chemistry of the counter ion in the studied complexes effectively tunes the solubility and improves the cycling stability. Whereas further studies are required to limit the solubility and active species shuttle, this study explores the bottlenecks of phendione - transition metal complexes as electrode materials for solid electrode format batteries. </i>


Author(s):  
Mardia T. El Sayed ◽  
Ibrahim H.I. Habib ◽  
Nermien M. Sabry ◽  
Sergey A. Pisarev ◽  
Mohamed El-Naggar ◽  
...  

Absorption spectra of tetrahydro[3,2-b]indolo-carbazoles (THICZs) with various molecular size and alkyl tails have been recorded in various solvents in the range between 200 to 600 nm. The photo physical behaviour of dissolved THICZs depends on the nature of its environment. The solvatochromic behaviours of THICZs and solvent solute interactions can be analysed by means of linear solvation energy relationships concept proposed by Kamlet and Taft. Compound 4 show excellent properties for sensing small molecules. The electrochemical behaviour of some THICZs was investigated at carbon paste electrode where two electrode reactions were involved, irreversible oxidation-one electron transfer and quasi-reversible redox reactions forming phenolic followed by quinolone moiety electro active species. The DFT-calculated molecular orbital energies (B3LYP/6-31G) and HOMO-LUMO gaps for some presented indolocarbazoles have been performed.


2021 ◽  
Vol 86 (3) ◽  
Author(s):  
Jeffery M. Allen ◽  
Justin Chang ◽  
Francois L. E. Usseglio-Viretta ◽  
Peter Graf ◽  
Kandler Smith

AbstractBattery performance is strongly correlated with electrode microstructure. Electrode materials for lithium-ion batteries have complex microstructure geometries that require millions of degrees of freedom to solve the electrochemical system at the microstructure scale. A fast-iterative solver with an appropriate preconditioner is then required to simulate large representative volume in a reasonable time. In this work, a finite element electrochemical model is developed to resolve the concentration and potential within the electrode active materials and the electrolyte domains at the microstructure scale, with an emphasis on numerical stability and scaling performances. The block Gauss-Seidel (BGS) numerical method is implemented because the system of equations within the electrodes is coupled only through the nonlinear Butler–Volmer equation, which governs the electrochemical reaction at the interface between the domains. The best solution strategy found in this work consists of splitting the system into two blocks—one for the concentration and one for the potential field—and then performing block generalized minimal residual preconditioned with algebraic multigrid, using the FEniCS and the Portable, Extensible Toolkit for Scientific Computation libraries. Significant improvements in terms of time to solution (six times faster) and memory usage (halving) are achieved compared with the MUltifrontal Massively Parallel sparse direct Solver. Additionally, BGS experiences decent strong parallel scaling within the electrode domains. Last, the system of equations is modified to specifically address numerical instability induced by electrolyte depletion, which is particularly valuable for simulating fast-charge scenarios relevant for automotive application.


Author(s):  
Kaixiang Zou ◽  
Yuanfu Deng ◽  
Weijing Wu ◽  
Shiwei Zhang ◽  
Guohua Chen

High performance carbon-based materials are ideal electrode materials for Li-ion capacitors (LICs), but there are still many challenges such as the complicated preparation preocesses, high cost and low yield. Also,...


Author(s):  
Kathryn Holguin ◽  
Motahareh Mohammadiroudbari ◽  
Kaiqiang Qin ◽  
Chao Luo

Na-ion batteries (NIBs) are promising alternatives to Li-ion batteries (LIBs) due to the low cost, abundance, and high sustainability of sodium resources. However, the high performance of inorganic electrode materials...


2019 ◽  
Vol 7 (41) ◽  
pp. 23679-23726 ◽  
Author(s):  
Manoj K. Jangid ◽  
Amartya Mukhopadhyay

Monitoring stress development in electrodes in-situ provides a host of real-time information on electro-chemo-mechanical aspects as functions of SOC and electrochemical potential.


ChemPhysChem ◽  
2014 ◽  
Vol 15 (10) ◽  
pp. 1922-1938 ◽  
Author(s):  
Nicolas Dupré ◽  
Marine Cuisinier ◽  
Jean-Frederic Martin ◽  
Dominique Guyomard

Ionics ◽  
2008 ◽  
Vol 14 (5) ◽  
pp. 371-376 ◽  
Author(s):  
K. Zaghib ◽  
A. Mauger ◽  
F. Gendron ◽  
M. Massot ◽  
C. M. Julien

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