Depth profiling the solid electrolyte interphase on lithium titanate (Li4Ti5O12) using synchrotron-based photoelectron spectroscopy

Nordh, Tim; Younesi, Reza; Brandell, Daniel; Edström, Kristina

doi:10.1016/j.jpowsour.2015.06.038

Cited by 47 publications

(54 citation statements)

References 30 publications

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“…This observation is also in accordance with the ever-increasing signals of carbon and oxygen (primarily O 1s signals not corresponding to the bulk; Figure SI-3) from electrolyte decomposition products, and with our previous results. [41] The SEI on LTO would be thinner than any SEI found on graphite or silicon electrodes, since bulk peaks can still be observed.…”

Section: Survey Spectramentioning

confidence: 95%

“…In contrast to previous surface studies by our group on LTO (employing PVdF-HFP), the active material content was increased by 15 wt.% to a more sensible amount of 90 wt.% LTO. [41,42] The relative ratio between conductive additive (4 wt.%) and binder (6 wt.%) remained the same, since previous studies have demonstrated that a 2 : 3 ratio (by weight) for carbon black:PVdF provided the best tradeoff with respect to adhesion and coherence of the coating, as well as electronic conductivity. [43,44] It should be noted that these changes might also be reflected in the XPS spectra, with respect to our earlier works.…”

Section: Survey Spectramentioning

confidence: 99%

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Different Shades of Li₄Ti₅O₁₂ Composites: The Impact of the Binder on Interface Layer Formation

et al. 2017

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Replacing the traditional PVdF(‐HFP) electrode binder with water‐soluble alternatives can potentially render electrode fabrication more environmentally benign. Herein, the surface layer formation of stored and cycled samples of two water‐based Li4Ti5O12 composites employing either poly(sodium acrylate) (PAA−Na) or sodium carboxymethyl cellulose (CMC−Na) as binders are studied with X‐ray photoelectron spectroscopy. In all three formulations, the surface layer composition formed upon storage differed notably from the solid‐electrolyte interphase (SEI) layer formed on cycled samples. The surface layer under open‐circuit conditions seems to originate mostly from the electrolyte salt (LiPF6) degradation. The comparison with cycled samples after 10 and 100 cycles shows a continuous build‐up of an SEI layer on PAA−Na and PVdF‐HFP electrodes. In contrast, on CMC−Na containing electrodes the SEI composition remains nearly unchanged. The results correlate well with the electrochemical behavior.

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Section: Survey Spectramentioning

confidence: 95%

Section: Survey Spectramentioning

confidence: 99%

Different Shades of Li₄Ti₅O₁₂ Composites: The Impact of the Binder on Interface Layer Formation

et al. 2017

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“…26 The differences in electrochemical behavior can then more easily be attributed to the modifications on the positive electrode. Even though LTO electrodes generate some electrolyte reduction, 27,28 this cell chemistry can still be considered a good base system to study the effect of electrolyte additives on the cathode side.…”

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confidence: 99%

The Effect of the Fluoroethylene Carbonate Additive in LiNi_0.5Mn_1.5O₄- Li₄Ti₅O₁₂Lithium-Ion Cells

Aktekin

Younesi

Zipprich³

et al. 2017

J. Electrochem. Soc.

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The effect of the electrolyte additive fluoroethylene carbonate (FEC) for Li-ion batteries has been widely discussed in literature in recent years. Here, the additive is studied for the high-voltage cathode LiNi 0.5 Mn 1.5 O 4 (LNMO) coupled to Li 4 Ti 5 O 12 (LTO) to specifically study its effect on the cathode side. Electrochemical performance of full cells prepared by using a standard electrolyte (LP40) with different concentrations of FEC (0, 1 and 5 wt%) were compared and the surface of cycled positive electrodes were analyzed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The results show that addition of FEC is generally of limited use for this battery system. Addition of 5 wt% FEC results in relatively poor cycling performance, while the cells with 1 wt% FEC showed similar behavior compared to reference cells prepared without FEC. SEM and XPS analysis did not indicate the formation of thick surface layers on the LNMO cathode, however, an increase in layer thickness with increased FEC content in the electrolyte could be observed. XPS analysis on LTO electrodes showed that the electrode interactions between positive and negative electrodes occurred as Mn and Ni were detected on the surface of LTO already after 1 cycle. 1 In addition to the high voltage plateau, the intrinsic structure of the spinel phase allows fast lithiation and de-lithiation kinetics 2,3 which is attributed to the 3-D lithium transport among the available tunnels in the crystal. 4 The advantage of higher voltage (thus higher energy density) and good power capability are two main reasons behind the growing interest for this material, especially for electric vehicle applications. However, the electrode material is prone to side reactions with conventional electrolytes, not least electrolyte decomposition at high voltages and transition metal dissolution from the spinel structure, particularly observed at elevated temperatures. These obstacles need to be resolved before wide-scale commercial application of LNMO electrodes. 5,6 One possible approach to overcome these problems is to use electrolyte additives that could ideally form an in-situ passivating layer on the positive electrode surface, similarly to the solid electrolyte interphase (SEI) observed on negative LiB electrodes. 7,8 A number of electrolyte additives have been reported in recent years for the purpose of passivating the cathode/electrolyte interface at high operating voltages.7 Some of these additives include LiBOB, 9 succinic anhydride, 10 HFiP 11 and DMMP. 12 It is important to note that the use of such cathode interface additives should also be compatible with the anode interface in full cells, or vice versa for additives intended for the anode side. Therefore, it is essential to study the effect of anode additives on the cathode side as well, if new fullcell chemistries are to be realized. Fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are common examples of such additives where the former has been used mostly to improve an...

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“…Although some degradation has been observed on LTO electrodes, it is suggested to most likely be formed due to the adsorption of species on the LTO surface, which were formed on the positive electrode . Surface layer formation on LTO has, however, been observed after cycling in a “half‐cell” setup using Li as a negative electrode, thereby showing that adsorption of “cross‐talk” species formed at the positive electrode is not necessary to observe such a phenomenon . Furthermore, it was observed that by soaking the LTO electrodes in an electrolyte, a surface layer was formed without the presence of any other electrode .…”

Section: Introductionmentioning

confidence: 99%

“…[31,32] Furthermore, it was observed that by soaking the LTO electrodes in an electrolyte, a surface layer was formed without the presence of any other electrode. [31] Despite the formation of a surface layer on LTO, it is to a smaller extent than that observed for other negative electrode materials such as graphite or a lithium foil. [33,34] The surface layer on LTO does not necessarily consist of only degraded electrolyte species; also, manganese can be deposited on the surface when LTO has been cycled against LiMn 2 O 4 .…”

Section: Introductionmentioning

confidence: 99%

Temperature Dependence of Electrochemical Degradation in LiNi_1/3Mn_1/3Co_1/3O₂/Li₄Ti₅O₁₂ Cells

et al. 2019

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Aging mechanisms in lithium‐ion batteries are dependent on the operational temperature, but the detailed mechanisms on what processes take place at what temperatures are still lacking. The electrochemical performance and capacity fading of the common cell chemistry LiNi1/3Mn1/3Co1/3O2 (NMC)/Li4Ti5O12 (LTO) pouch cells are studied at temperatures 10, 30, and 55 °C. The full cells are cycled with a moderate upper cutoff potential of 4.3 V versus Li+/Li. The electrode interfaces are characterized postmortem using photoelectron spectroscopy techniques (soft X‐ray photoelectron spectroscopy [SOXPES], hard X‐ray photoelectron spectroscopy [HAXPES], and X‐ray absorption near edge structure [XANES]). Stable cycling at 30 °C is explained by electrolyte reduction forming a stabilizing interphase, thereby preventing further degradation. This initial reaction, between LTO and the electrolyte, seems to be beneficial for the NMC–LTO full cell. At 55 °C, continuous electrolyte reduction and capacity fading are observed. It leads to the formation of a thicker surface layer of organic species on the LTO surface than at 30 °C, contributing to an increased voltage hysteresis. At 10 °C, large cell‐resistances are observed, caused by poor electrolyte conductivity in combination with a relatively thicker and LixPFy‐rich surface layer on LTO, which limit the capacity.

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Depth profiling the solid electrolyte interphase on lithium titanate (Li4Ti5O12) using synchrotron-based photoelectron spectroscopy

Cited by 47 publications

References 30 publications

Different Shades of Li₄Ti₅O₁₂ Composites: The Impact of the Binder on Interface Layer Formation

Different Shades of Li₄Ti₅O₁₂ Composites: The Impact of the Binder on Interface Layer Formation

The Effect of the Fluoroethylene Carbonate Additive in LiNi_0.5Mn_1.5O₄- Li₄Ti₅O₁₂Lithium-Ion Cells

Temperature Dependence of Electrochemical Degradation in LiNi_1/3Mn_1/3Co_1/3O₂/Li₄Ti₅O₁₂ Cells

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Depth profiling the solid electrolyte interphase on lithium titanate (Li4Ti5O12) using synchrotron-based photoelectron spectroscopy

Cited by 47 publications

References 30 publications

Different Shades of Li4Ti5O12 Composites: The Impact of the Binder on Interface Layer Formation

Different Shades of Li4Ti5O12 Composites: The Impact of the Binder on Interface Layer Formation

The Effect of the Fluoroethylene Carbonate Additive in LiNi0.5Mn1.5O4- Li4Ti5O12Lithium-Ion Cells

Temperature Dependence of Electrochemical Degradation in LiNi1/3Mn1/3Co1/3O2/Li4Ti5O12 Cells

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Different Shades of Li₄Ti₅O₁₂ Composites: The Impact of the Binder on Interface Layer Formation

Different Shades of Li₄Ti₅O₁₂ Composites: The Impact of the Binder on Interface Layer Formation

The Effect of the Fluoroethylene Carbonate Additive in LiNi_0.5Mn_1.5O₄- Li₄Ti₅O₁₂Lithium-Ion Cells

Temperature Dependence of Electrochemical Degradation in LiNi_1/3Mn_1/3Co_1/3O₂/Li₄Ti₅O₁₂ Cells