| Records |
| Author |
Çakir, D.; Sevik, C.; Gulseren, O.; Peeters, F.M. |
| Title |
Mo2C as a high capacity anode material: a first-principles study |
Type |
A1 Journal article |
| Year |
2016 |
Publication |
Journal of materials chemistry A : materials for energy and sustainability |
Abbreviated Journal |
J Mater Chem A |
| Volume |
4 |
Issue |
16 |
Pages |
6029-6035 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
| Abstract |
The adsorption and diffusion of Li, Na, K and Ca atoms on a Mo2C monolayer are systematically investigated by using first principles methods. We found that the considered metal atoms are strongly bound to the Mo2C monolayer. However, the adsorption energies of these alkali and earth alkali elements decrease as the coverage increases due to the enhanced repulsion between the metal ions. We predict a significant charge transfer from the ad-atoms to the Mo2C monolayer, which indicates clearly the cationic state of the metal atoms. The metallic character of both pristine and doped Mo2C ensures a good electronic conduction that is essential for an optimal anode material. Low migration energy barriers are predicted as small as 43 meV for Li, 19 meV for Na and 15 meV for K, which result in the very fast diffusion of these atoms on Mo2C. For Mo2C, we found a storage capacity larger than 400 mA h g(-1) by the inclusion of multilayer adsorption. Mo2C expands slightly upon deposition of Li and Na even at high concentrations, which ensures the good cyclic stability of the atomic layer. The calculated average voltage of 0.68 V for Li and 0.30 V for Na ions makes Mo2C attractive for low charging voltage applications. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication  |
Cambridge |
Editor |
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| Language |
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Wos |
000374790700033 |
Publication Date |
2016-03-18 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2050-7488; 2050-7496 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
8.867 |
Times cited |
202 |
Open Access |
|
| Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by TUBITAK ULAKBIM, High Performance and Grid Computing Center (TR-Grid e-Infrastructure), and HPC infrastructure of the University of Antwerp (CalcUA) a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. C. S. acknowledges the support from Turkish Academy of Sciences (TUBA-GEBIP). C. S acknowledges the support from Anadolu University (Grant No. 1407F335). We acknowledge the support from TUBITAK, The Scientific and Technological Research Council of Turkey (Grant No. 115F024). ; |
Approved |
Most recent IF: 8.867 |
| Call Number |
UA @ lucian @ c:irua:144763 |
Serial |
4669 |
| Permanent link to this record |
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| Author |
Ben Dkhil, S.; Pfannmöller, M.; Ata, I.; Duche, D.; Gaceur, M.; Koganezawa, T.; Yoshimoto, N.; Simon, J.-J.; Escoubas, L.; Videlot-Ackermann, C.; Margeat, O.; Bals, S.; Bauerle, P.; Ackermann, J. |
| Title |
Time evolution studies of dithieno[3,2-b:2 ',3 '-d] pyrrole-based A-D-A oligothiophene bulk heterojunctions during solvent vapor annealing towards optimization of photocurrent generation |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Journal of materials chemistry A : materials for energy and sustainability |
Abbreviated Journal |
J Mater Chem A |
| Volume |
5 |
Issue |
5 |
Pages |
1005-1013 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
Solvent vapor annealing (SVA) is one of the main techniques to improve the morphology of bulk heterojunction solar cells using oligomeric donors. In this report, we study time evolution of nanoscale morphological changes in bulk heterojunctions based on a well-studied dithienopyrrole-based A-D-A oligothiophene (dithieno[3,2-b: 2',3'-d] pyrrole named here 1) blended with [6,6]-phenyl-C-71-butyric acid methyl ester (PC71BM) to increase photocurrent density by combining scanning transmission electron microscopy and low-energy-loss spectroscopy. Our results show that SVA transforms the morphology of 1 : PC71BM blends by a three-stage mechanism: highly intermixed phases evolve into nanostructured bilayers that correspond to an optimal blend morphology. Additional SVA leads to completely phaseseparated micrometer-sized domains. Optical spacers were used to increase light absorption inside optimized 1 : PC71BM blends leading to solar cells of 7.74% efficiency but a moderate photocurrent density of 12.3 mA cm (-2). Quantum efficiency analyses reveal that photocurrent density is mainly limited by losses inside the donor phase. Indeed, optimized 1 : PC71BM blends consist of large donor-enriched domains not optimal for exciton to photocurrent conversion. Shorter SVA times lead to smaller domains; however they are embedded in large mixed phases suggesting that introduction of stronger molecular packing may help us to better balance phase separation and domain size enabling more efficient bulk heterojunction solar cells. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Cambridge |
Editor |
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| Language |
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Wos |
000394430800018 |
Publication Date |
2016-11-30 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2050-7488; 2050-7496 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
8.867 |
Times cited |
19 |
Open Access |
Not_Open_Access |
| Notes |
; We acknowledge financial support by the French Fond Unique Interministeriel (FUI) under the project “SFUMATO” (Grant number: F1110019V/201308815) as well as by the European Commission under the Project “SUNFLOWER” (FP7-ICT-2011-7, Grant number: 287594). The synchrotron radiation experiments were performed at BL19B2 in SPring-8 with the approval of Japan Synchrotron Radiation Research Institute (JASRI) (Proposal No. 2016A1568). We further acknowledge financial support via ERC Starting Grant Colouratoms (335078). ; |
Approved |
Most recent IF: 8.867 |
| Call Number |
UA @ lucian @ c:irua:142602UA @ admin @ c:irua:142602 |
Serial |
4695 |
| Permanent link to this record |
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| Author |
Aierken, Y.; Sevik, C.; Gulseren, O.; Peeters, F.M.; Çakir, D. |
| Title |
MXenes/graphene heterostructures for Li battery applications : a first principles study |
Type |
A1 Journal article |
| Year |
2018 |
Publication |
Journal of materials chemistry A : materials for energy and sustainability |
Abbreviated Journal |
J Mater Chem A |
| Volume |
6 |
Issue |
5 |
Pages |
2337-2345 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
| Abstract |
MXenes are the newest class of two-dimensional (2D) materials, and they offer great potential in a wide range of applications including electronic devices, sensors, and thermoelectric and energy storage materials. In this work, we combined the outstanding electrical conductivity, that is essential for battery applications, of graphene with MXene monolayers (M2CX2 where M = Sc, Ti, V and X = OH, O) to explore its potential in Li battery applications. Through first principles calculations, we determined the stable stacking configurations of M2CX2/graphene bilayer heterostructures and their Li atom intercalation by calculating the Li binding energy, diffusion barrier and voltage. We found that: (1) for the ground state stacking, the interlayer binding is strong, yet the interlayer friction is small; (2) Li binds more strongly to the O-terminated monolayer, bilayer and heterostructure MXene systems when compared with the OHterminated MXenes due to the H+ induced repulsion to the Li atoms. The binding energy of Li decreases as the Li concentration increases due to enhanced repulsive interaction between the positively charged Li ions; (3) Ti2CO2/graphene and V2CO2/graphene heterostructures exhibit large Li atom binding energies making them the most promising candidates for battery applications. When fully loaded with Li atoms, the binding energy is -1.43 eV per Li atom and -1.78 eV per Li atom for Ti2CO2/graphene and V2CO2/graphene, respectively. These two heterostructures exhibit a nice compromise between storage capacity and kinetics. For example, the diffusion barrier of Li in Ti2CO2/graphene is around 0.3 eV which is comparable to that of graphite. Additionally, the calculated average voltages are 1.49 V and 1.93 V for Ti2CO2/graphene and V2CO2/graphene structures, respectively; (4) a small change in the in-plane lattice parameters (<1%), interatomic bond lengths and interlayer distances (<0.5 angstrom) proves the stability of the heterostructures against Li intercalation, and the impending phase separation into constituent layers and capacity fading during charge-discharge cycles in real battery applications; (5) as compared to bare M2CX2 bilayers, M2CX2/graphene heterostructures have lower molecular mass, offering high storage capacity; (6) the presence of graphene ensures good electrical conductivity that is essential for battery applications. Given these advantages, Ti2CO2/graphene and V2CO2/graphene heterostructures are predicted to be promising for lithium-ion battery applications. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Cambridge |
Editor |
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| Language |
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Wos |
000423981200049 |
Publication Date |
2018-01-02 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
|
| ISSN |
2050-7488; 2050-7496 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
8.867 |
Times cited |
131 |
Open Access |
|
| Notes |
; This work was supported by the bilateral project between the Scientific and Technological Research Council of Turkey (TUBITAK) and FWO-Flanders, Flemish Science Foundation (FWO-Vl) and the Methusalem foundation of the Flemish government. Computational resources were provided by the TUBITAK ULAKBIM, High Performance and Grid Computing Center (TRGrid e-Infrastructure), and HPC infrastructure of the University of Antwerp (CalcUA) a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. We acknowledge the support from the TUBITAK (Grant No. 115F024 and 116F080). Part of this work was supported by the BAGEP Award of the Science Academy. ; |
Approved |
Most recent IF: 8.867 |
| Call Number |
UA @ lucian @ c:irua:149265UA @ admin @ c:irua:149265 |
Serial |
4945 |
| Permanent link to this record |
