Safety characteristics of Li(Ni0.8Co0.15Al0.05)O2 and Li(Ni1/3Co1/3Mn1/3)O2

Belharouak, Ilias; Lu, Wenquan; Vissers, D.R.; Amine, Khalil

doi:10.1016/j.elecom.2005.12.007

Cited by 259 publications

(213 citation statements)

References 13 publications

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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: 79%

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.

948

1,278

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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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Section: Discussionsupporting

confidence: 79%

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.

948

1,278

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“…[42][43][44][45] Hwang and coworkers studied the correlation between the gas evolution and phase transition in highly delithiated nickel-rich cathode by conducting combined in situ time resolved-X-ray diffractometer with mass spectroscopy (MS). [46] The points that phase transition occurs (from layered structure to spinel structure and from spinel structure to rock salt structure) precisely coincided with the oxygen gas release peaks.…”

Section: Phase Transitionmentioning

confidence: 99%

Prospect and Reality of Ni‐Rich Cathode for Commercialization

Kim

Lee

Cha

et al. 2017

Advanced Energy Materials

639

582

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practical candidate for the wide application of the LIBs with respect to the reversible capacity, rate capability, and capital cost. [4][5][6][7] In terms of nickel contents, the nickel-rich cathodes with nickel content above 80% have advantages in gravimetric capacity, allowing high gravimetric energy density, compared with the nickel content less than 80%. Currently, the nickel-rich cathodes with the amount of nickel less than 60% are fully commercialized. However, the nickel-rich cathodes with nickel content of ≥80% still have many difficulties in the commercialization with respect to powder properties and electrode fabrication process.The unstable powder properties originate from residual lithium compounds such as LiOH and Li 2 CO 3 that formed by the spontaneous reduction of sensitive trivalent nickel ions during the synthesis process and storage in air. [8][9][10][11] The Li 2 CO 3 significantly promotes the gas evolution and increase the moisture of the cathode powder, which strongly related to the safety issue. [12][13][14] Furthermore, the LiOH on the cathode increases the powder pH value, causing the gelation of the slurry during the electrode fabrication process. The nickel-rich cathode with nickel content of ≤60% have acceptable amount of residual lithium compounds for the practical use. By contrast, the cathode with amount of nickel of ≥80% should be treated by additional process to reduce the residual lithium compounds ( Table 1). Furthermore, other powder properties, such as powder pH and moisture, should be carefully controlled when nickel contents were exceeded of ≥80%. Thus, for the practical application of these cathode materials, most battery companies have adapted the washing process, in which the cathode power was stirred in purified water for 20-40 min. [15,16] The washing process could greatly reduce the residual lithium compounds and powder pH value. [15] However, the washing process not only increases process time and capital cost but also make the nickel-rich cathode more chemically sensitive than nonwashed cathodes. [16] More seriously, the water washing deteriorates the thermal stability of the nickel-rich cathodes, indicating that the washing process should be substituted by other methods for the battery safety.Another important factor for the commercialization of the nickel-rich cathodes is the electrode density directly related to the energy density. In general, the nickel-rich cathodesThe layered nickel-rich cathode materials are considered as promising cathode materials for lithium-ion batteries (LIBs) due to their high reversible capacity and low cost. However, several significant challenges, such as the unstable powder properties and limited electrode density, hindered the practical application of the nickel-rich cathode materials with the nickel content over 80%. Herein, important stability issues and in-depth understanding of the nickel-rich cathode materials on the basis of the industrial electrode fabrication condition for the commercialization of the nickel-rich cathode m...

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“…Fig. 3 shows Nyquist plots of the bare and 0.1 wt% PP-coated NCS electrode in the charged state of 4.3 V. The high-frequency semicircle is attributed to the resistance of the solid electrolyte interphase (SEI) film (R S E I ), and the second semicircle that appears at lower frequency is associated with the charge transfer resistance (R ct ) [10,11]. The SEI film is formed by contact between the oxygen generated in the charging process and the electrolyte.…”

Section: Resultsmentioning

confidence: 99%

Improvement of Electrochemical Properties and Thermal Stability of a Ni-rich Cathode Material by Polypropylene Coating

Yoo¹,

Son²

2016

Journal of Electrochemical Science and Technology

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The interface between the surface of a cathode material and the electrolyte gives rise to surface reactions such as solid electrolyte interface (SEI) and chemical side reactions. These reactions lead to increased surface resistance and charge transfer resistance. It is consequently necessary to improve the electrochemical characteristics by suppressing these reactions. In order to suppress unnecessary surface reactions, we coated cathode material using polypropylene (PP). The PP coating layer effectively reduced the SEI film that is generated after a 4.3 V initial charging process. By mitigating the formation of the SEI film, the PP-coated Li[(Ni 0.6 Co 0.1 Mn 0.3 ) 0.36 (Ni 0.80 Co 0.15 Al 0.05 ) 0.64 )]O 2 (NCS) electrode provided enhanced transport of Li + ions due to reduced SEI resistance (R SEI ) and charge transfer resistance (R ct ). The initial charge and discharge efficiency of the PP-coated NCS electrode was 96.2 % at a current density of 17 mA/g in a voltage range of 3.0 ~ 4.3 V, whereas the efficiency of the NCS electrode was only 94.7 %. The presence of the protective PP layer on the cathode improved the thermal stability by reducing the generated heat, and this was confirmed via DSC analysis by an increased exothermic peak.

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Safety characteristics of Li(Ni0.8Co0.15Al0.05)O2 and Li(Ni1/3Co1/3Mn1/3)O2

Cited by 259 publications

References 13 publications

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

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

Prospect and Reality of Ni‐Rich Cathode for Commercialization

Improvement of Electrochemical Properties and Thermal Stability of a Ni-rich Cathode Material by Polypropylene Coating

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Safety characteristics of Li(Ni0.8Co0.15Al0.05)O2 and Li(Ni1/3Co1/3Mn1/3)O2

Cited by 259 publications

References 13 publications

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

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

Prospect and Reality of Ni‐Rich Cathode for Commercialization

Improvement of Electrochemical Properties and Thermal Stability of a Ni-rich Cathode Material by Polypropylene Coating

Contact Info

Product

Resources

About

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

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