Effect of AlF3Coating on Thermal Behavior of Chemically Delithiated Li0.35[Ni1/3Co1/3Mn1/3]O2

Myung, Seung‐Taek; Lee, Kisoo; Yoon, Chong Seung; Sun, Yang Kook; Amine, Khalil; Yashiro, Hitoshi

doi:10.1021/jp9082322

Cited by 104 publications

(68 citation statements)

References 36 publications

(55 reference statements)

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“…The thermal stability decreases and the temperature of the main exothermic reaction is shifted to~236 • C. The ratio between the exothermic peaks changes and the heat release increases more than twofold. Such differences may be related to the surface and bulk changes of the cathode material upon cycling, and the results obtained correlate well with previous reports [58][59][60][61]. To summarize, the surface modification by AlF 3 coating of these Li-and Mn-rich cathode materials improves their thermal stability in pristine and delithiated states compared to the uncoated electrodes.…”

Section: Modifications Of XLIsupporting

confidence: 89%

Study of Cathode Materials for Lithium-Ion Batteries: Recent Progress and New Challenges

et al. 2017

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Amongst a number of different cathode materials, the layered nickel-rich LiNi y Co x Mn 1−y−x O 2 and the integrated lithium-rich xLi 2 MnO 3 ·(1 − x)Li[Ni a Co b Mn c ]O 2 (a + b + c = 1) have received considerable attention over the last decade due to their high capacities of~195 and~250 mAh·g −1 , respectively. Both materials are believed to play a vital role in the development of future electric vehicles, which makes them highly attractive for researchers from academia and industry alike. The review at hand deals with both cathode materials and highlights recent achievements to enhance capacity stability, voltage stability, and rate capability, etc. The focus of this paper is on novel strategies and established methods such as coatings and dopings.

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Section: Modifications Of XLIsupporting

confidence: 89%

Study of Cathode Materials for Lithium-Ion Batteries: Recent Progress and New Challenges

et al. 2017

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“…In other words, the NMC structure is thermodynamically unstable at high degrees of delithiation, and only retains its oxygen and its layered bulk structure due to the kinetically hindered oxygen diffusion. This hypothesis is supported by the literature, where it is reported that layered NMC 21,25,27,70,71 and NCA 22,25,26,70 structures in the charged state (low lithium content) are not stable at high temperatures (> 170…”

Section: Discussionsupporting

confidence: 74%

Oxygen Release and Its Effect on the Cycling Stability of LiNi_xMn_yCo_zO₂(NMC) Cathode Materials for Li-Ion Batteries

Jung

Metzger

Maglia

et al. 2017

J. Electrochem. Soc.

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Layered LiNi x Mn y Co z O 2 (NMC) is a widely used class of cathode materials with LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC111) being the most common representative. However, Ni-rich NMCs are more and more in the focus of current research due to their higher specific capacity and energy. In this work we will compare LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC111), LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622), and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) with respect to their cycling stability in NMC-graphite full-cells at different end-of-charge potentials. It will be shown that stable cycling is possible up to 4.4 V for NMC111 and NMC622 and only up to 4.0 V for NMC811. At higher potentials, significant capacity fading was observed, which was traced back to an increase in the polarization of the NMC electrode, contrary to the nearly constant polarization of the graphite electrode. Furthermore, we show that the increase in the polarization occurs when the NMC materials are cycled up to a high-voltage feature in the dq/dV plot, which occurs at ∼4.7 V vs. Li/Li + for NMC111 and NMC622 and at ∼4.3 V vs. Li/Li + for NMC811. For the latter material, this feature corresponds to the H2 → H3 phase transition. Contrary to the common understanding that the electrochemical oxidation of carbonate electrolytes causes the CO 2 and CO evolution at potentials above 4.7 V vs. Li/Li + , we believe that the observed CO 2 and CO are mainly due to the chemical reaction of reactive lattice oxygen with the electrolyte. This hypothesis is based on gas analysis using On-line Electrochemical Mass Spectrometry (OEMS), by which we prove that all three materials release oxygen from the particle surface and that the oxygen evolution coincides with the onset of CO 2 and CO evolution. Interestingly, the onsets of oxygen evolution for the different NMCs correlate well with the high-voltage redox feature at ∼4.7 V vs. Li/Li + for NMC111 and NMC622 as well as at ∼4.3 V vs. Li/Li + for NMC811. To support this hypothesis, we show that no CO 2 or CO is evolved for the LiNi 0.43 Mn 1.57 O 4 (LNMO) spinel up to 5 V vs. Li/Li + , consistent with the absence of oxygen release. Lastly, we demonstrate by the use of 13 C labeled conductive carbon that it is the electrolyte rather than the conductive carbon which is oxidized by the released lattice oxygen. Taking these findings into consideration, a mechanism is proposed for the reaction of released lattice oxygen with ethylene carbonate yielding CO 2 , CO, and Li-Ion batteries have recently been used as power supply for electric vehicles (EVs). In order to penetrate the mass market, a significant reduction in costs and further performance improvements have to be achieved to realize a longer driving range of EVs.1 The latter highly depends on the choice of the cathode active material, for which several potential materials exist, 2 of which layered lithium nickel manganese cobalt oxide (LiNi x Mn y Co z O 2 , NMC) is one of the most promising class of cathode materials.3 This is due to the high specific capacity and good stability of the lay...

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“…Due to the large amount of Mn in the shell, the oxidation state of Mn is close to tetravalent and the oxidation state of Ni is close to Ni 2 + , slightly higher than 2 + based on XPS data (Supporting Information, Figure S1) which is similar to our previous results of Li [ [19] We considered two possibilities for cation mixing: i) Li layer occupation of Ni 2 + from the transition metal layer, and ii) site exchange of Li + and Ni 2 + . The latter case always resulted in a smaller intensity of the difference between the observed and calculated patterns and better reliability factors (R wp and R p values), as shown in Table 2 and Table 3.…”

Section: Thermal Lithiation Of Cgcs Hydroxide Composed Of Nanoparticlsupporting

confidence: 89%

Nanorod and Nanoparticle Shells in Concentration Gradient Core–Shell Lithium Oxides for Rechargeable Lithium Batteries

et al. 2014

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The structure, electrochemistry, and thermal stability of concentration gradient core-shell (CGCS) particles with different shell morphologies were evaluated and compared. We modified the shell morphology from nanoparticles to nanorods, because nanorods can result in a reduced surface area of the shell such that the outer shell would have less contact with the corrosive electrolyte, resulting in improved electrochemical properties. Electron microscopy studies coupled with electron probe X-ray micro-analysis revealed the presence of a concentration gradient shell consisting of nanoparticles and nanorods before and after thermal lithiation at high temperature. Rietveld refinement of the X-ray diffraction data and the chemical analysis results showed no variations of the lattice parameters and chemical compositions of both produced CGCS particles except for the degree of cation mixing (or exchange) in Li and transition metal layers. As anticipated, the dense nanorods present in the shell gave rise to a high tap density (2.5 g cm(-3) ) with a reduced pore volume and surface area. Intimate contact among the nanorods is likely to improve the resulting electric conductivity. As a result, the CGCS Li[Ni0.60 Co0.15 Mn0.25 ]O2 with the nanorod shell retained approximately 85.5% of its initial capacity over 150 cycles in the range of 2.7-4.5 V at 60 °C. The charged electrode consisting of Li0.16 [Ni0.60 Co0.15 Mn0.25 ]O2 CGCS particles with the nanorod shell also displayed a main exothermic reaction at 279.4 °C releasing 751.7 J g(-1) of heat. Due to the presence of the nanorod shell in the CGCS particles, the electrochemical and thermal properties are substantially superior to those of the CGCS particles with the nanoparticle shell.

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Effect of AlF₃Coating on Thermal Behavior of Chemically Delithiated Li_0.35[Ni_1/3Co_1/3Mn_1/3]O₂

Cited by 104 publications

References 36 publications

Study of Cathode Materials for Lithium-Ion Batteries: Recent Progress and New Challenges

Study of Cathode Materials for Lithium-Ion Batteries: Recent Progress and New Challenges

Oxygen Release and Its Effect on the Cycling Stability of LiNi_xMn_yCo_zO₂(NMC) Cathode Materials for Li-Ion Batteries

Nanorod and Nanoparticle Shells in Concentration Gradient Core–Shell Lithium Oxides for Rechargeable Lithium Batteries

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Effect of AlF3Coating on Thermal Behavior of Chemically Delithiated Li0.35[Ni1/3Co1/3Mn1/3]O2

Cited by 104 publications

References 36 publications

Study of Cathode Materials for Lithium-Ion Batteries: Recent Progress and New Challenges

Study of Cathode Materials for Lithium-Ion Batteries: Recent Progress and New Challenges

Oxygen Release and Its Effect on the Cycling Stability of LiNixMnyCozO2(NMC) Cathode Materials for Li-Ion Batteries

Nanorod and Nanoparticle Shells in Concentration Gradient Core–Shell Lithium Oxides for Rechargeable Lithium Batteries

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Effect of AlF₃Coating on Thermal Behavior of Chemically Delithiated Li_0.35[Ni_1/3Co_1/3Mn_1/3]O₂

Oxygen Release and Its Effect on the Cycling Stability of LiNi_xMn_yCo_zO₂(NMC) Cathode Materials for Li-Ion Batteries