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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/25786

Title: Ti surface doping of LiNi0.5Mn1.5O4-δ positive electrodes for lithium ion batteries
Authors: Ulu Okudur, Fulya
D'Haen, Jan
Vranken, Thomas
De Sloovere, Dries
Verheijen, Maarten
Karakulina, M. Olesia
Abakumov, M. Artem
Hadermann, Joke
Van Bael, Marlies K.
Hardy, An
Issue Date: 2018
Citation: RSC Advances, 8(13), p. 7287-7300
Abstract: The particle surface of LiNi0.5Mn1.5O4-δ (LNMO), a Li-ion battery cathode material, has been modified by Ti cation doping through a hydrolysis-condensation reaction followed by an anneal in oxygen. The effect of different annealing temperatures (500-850oC) on the Ti distribution and electrochemical performance of the surface modified LNMO was investigated. Ti cations diffuse from the preformed amorphous ‘TiOx’ layer into the LNMO surface during annealing at 500oC. This results in a 2-4 nm thick Ti-rich spinel surface having lower Mn and Ni content compared to the core of the LNMO particles, which was observed with scanning transmission electron microscopy coupled with compositional EDX mapping. An increase in the annealing temperature promotes the formation of Ti bulk doped LiNi(0.5-w)Mn(1.5+w)-tTitO4 phase and Ti-rich LiNi0.5Mn1.5-yTiyO4 segregates above 750°C. Fourier-transform infrared spectrometry indicates an increasing Ni-Mn ordering withannealing temperature, for both bare and surface modified LNMO. Ti surface modified LNMO annealed at 500oC shows a superior cyclic stability, Coulombic efficiency and rate performance compared to bare LNMO annealed at 500oC when cycled at 3.4-4.9 V vs. Li/Li+. The improvements are probably due to suppressed Ni and Mn dissolution with Ti surface doping.
URI: http://hdl.handle.net/1942/25786
DOI: 10.1039/c7ra12932g
ISI #: 000425508900064
ISSN: 2046-2069
Category: A1
Type: Journal Contribution
Appears in Collections: Research publications

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