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Ulu Okudur, F.; Batuk, M.; Hadermann, J.; Safari, M.; De Sloovere, D.; Kumar Mylavarapu, S.; Joos, B.; D'Haen, J.; Van Bael, M.K.; Hardy, A. |
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Title |
Solution-gel-based surface modification of LiNi0.5Mn1.5O4-δ with amorphous Li-Ti-O coating |
Type |
A1 Journal article |
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Year  |
2023 |
Publication |
RSC advances |
Abbreviated Journal |
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Volume |
13 |
Issue |
47 |
Pages |
33146-33158 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
LNMO (LiNi0.5Mn1.5O4-delta) is a high-energy density positive electrode material for lithium ion batteries. Unfortunately, it suffers from capacity loss and impedance rise during cycling due to electrolyte oxidation and electrode/electrolyte interface instabilities at high operating voltages. Here, a solution-gel synthesis route was used to coat 0.5-2.5 mu m LNMO particles with amorphous Li-Ti-O (LTO) for improved Li conduction, surface structural stability and cyclability. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) analysis coupled with energy dispersive X-ray (EDX) showed Ti-rich amorphous coatings/islands or Ti-rich spinel layers on many of the LTO-modified LNMO facets, with a thickness varying from about 1 to 10 nm. The surface modification in the form of amorphous islands was mostly possible on high-energy crystal facets. Physicochemical observations were used to propose a molecular mechanism for the surface modification, combining insights from metalorganic chemistry with the crystallographic properties of LNMO. The improvements in functional properties were investigated in half cells. The cell impedance increased faster for the bare LNMO compared to amorphous LTO modified LNMO, resulting in R-ct values as high as 1247 Omega (after 1000 cycles) for bare LNMO, against 216 Omega for the modified material. At 10C, the modified material boosted a 15% increase in average discharge capacity. The improvements in electrochemical performance were attributed to the increase in electrochemically active surface area, as well as to improved HF-scavenging, resulting in the formation of protective byproducts, generating a more stable interface during prolonged cycling. |
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Wos |
001102666700001 |
Publication Date |
2023-11-09 |
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ISSN |
2046-2069 |
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Additional Links |
UA library record; WoS full record |
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Times cited |
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Open Access |
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no |
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Call Number |
UA @ admin @ c:irua:202091 |
Serial |
9096 |
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Author |
De Sloovere, D.; Safari, M.; Elen, K.; D'Haen, J.; Drozhzhin, O.A.; Abakumov, A.M.; Simenas, M.; Banys, J.; Bekaert, J.; Partoens, B.; Van Bael, M.K.; Hardy, A. |
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Title |
Reduced Na2+xTi4O9 composite : a durable anode for sodium-ion batteries |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
30 |
Issue |
23 |
Pages |
8521-8527 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Sodium-ion batteries (SIBs) are potential cost-effective solutions for stationary energy storage applications. Unavailability of suitable anode materials, however, is one of the important barriers to the maturity of SIBs. Here, we report a Na2+xTi4O9/C composite as a promising anode candidate for SIBs with high capacity and cycling stability. This anode is characterized by a capacity of 124 mAh g(-1) (plus 11 mAh g(-1) contributed by carbon black), an average discharge potential of 0.9 V vs Na/Na+, a good rate capability and a high stability (89% capacity retention after 250 cycles at a rate of 1 degrees C). The mechanisms of sodium insertion/deinsertion and of the formation of Na2+xTi4O9/C are investigated with the aid of various ex/in situ characterization techniques. The in situ formed carbon is necessary for the formation of the reduced sodium titanate. This synthesis method may enable the convenient synthesis of other composites of crystalline phases with amorphous carbon. |
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Wos |
000453489300014 |
Publication Date |
2018-11-29 |
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ISSN |
0897-4756 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
7 |
Open Access |
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Notes |
; This work was supported by the FWO (Research Foundation Flanders, project G040116). O.A.D. and A.M.A. are grateful to the Russian Science Foundation for financial support (Grant 17-73-30006). The authors acknowledge Pieter Samyn for Raman spectroscopy, Fulya Ulu Okudur for preliminary TEM, Bart Ruttens for XRD, Hilde Pellaers for SEM, Tom Haeldermans for elemental analysis, and Karen Leyssen and Vera Meynen for physisorption measurements. ; |
Approved |
Most recent IF: 9.466 |
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Call Number |
UA @ admin @ c:irua:156235 |
Serial |
5227 |
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