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Encasing Si particl...
Encasing Si particles within a versatile TiO2−xFx layer as an extremely reversible anode for high energy-density lithium-ion battery
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- Ma, Yue (författare)
- Uppsala universitet,Strukturkemi
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- Asfaw, Habtom Desta (författare)
- Uppsala universitet,Strukturkemi
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- Liu, Chenjuan (författare)
- Uppsala universitet,Strukturkemi
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- Wei, Bingqing (författare)
- Centre for Nano Energy Materials, State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, China; Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States
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- Edström, Kristina (författare)
- Uppsala universitet,Strukturkemi
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(creator_code:org_t)
- Elsevier BV, 2016
- 2016
- Engelska.
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Ingår i: Nano Energy. - : Elsevier BV. - 2211-2855. ; 30, s. 745-755
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https://uu.diva-port...
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https://doi.org/10.1...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- The chemical phenomena occurring at the electrode-electrolyte interfaces profoundly determine the cycle behavior of a lithium ion battery. In this work, we report that silicon-based anodes can attain enhanced levels of capacity retention, rate performance and lifespan when a versatile protective layer of, F-doped anatase (TiO2−xFx), is applied towards taming the interfacial chemistry of the silicon particles. With careful choice of titanium fluoride as a precursor, internal voids can be generated upon in-situ fluoride etching of the native oxide layer and are used to alleviate the mechanical stress caused by volume expansion of silicon during cycling. In the course of F-doping, part of the Ti4+(d0) ions in anatase are reduced to Ti3+(d1), thereby increasing charge carriers in the crystal structure. Hence, the multifunctional F-doped TiO2−x coating, not only minimizes the direct exposure of the Si surface to the electrolyte, but also improves the electronic conductivity via inter-valence electron hopping. The best-performing composite electrode, Si@TiO2−xFx-3, delivered a satisfactory performance in both half-cell and full-cell configurations. Furthermore, we present a study of 1) the Si valence change at the buried interface using synchrotron based hard X-ray photoelectron spectroscopy, and 2) the phase transformation of the electrode monitored in operando using X-ray diffraction. Based on these characterizations, we observe that the Li+ conducting intermediate phase (LixTiO2−xFx) formed inside the surface coating enables deep lithiation and delithiation of the silicon during battery operation, and thus increase the capacity that can be accessed from the electrodes.
Ämnesord
- NATURVETENSKAP -- Kemi -- Materialkemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences -- Materials Chemistry (hsv//eng)
Nyckelord
- Si anode
- Versatile interfacial layer
- Operando X-ray Diffraction
- Kinetic activation
- High energy-density
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- ref (ämneskategori)
- art (ämneskategori)
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