Tuning the Activity of Oxygen in LiNi0.8Co0.15Al0.05O2 Battery Electrodes

Karki, Khim; Huang, Yiqing; Hwang, Sooyeon; Gamalski, Andrew D.; Whittingham, M. Stanley; Zhou, Guangwen; Stach, Eric A.

doi:10.1021/acsami.6b09585

Cited by 57 publications

(62 citation statements)

References 43 publications

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“…Heat accumulated during electrochemical cycling could lead to a significant temperature increase during battery operation and eventually thermal runaway. Thus, heating-accelerated structural degradation has been accepted as a validated approach for the study of layered cathode using XRD 25–27 and TEM 8,24,28 . Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%

Coupling of electrochemically triggered thermal and mechanical effects to aggravate failure in a layered cathode

et al. 2018

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Electrochemically driven functioning of a battery inevitably induces thermal and mechanical effects, which in turn couple with the electrochemical effect and collectively govern the performance of the battery. However, such a coupling effect, whether favorable or detrimental, has never been explicitly elucidated. Here we use in situ transmission electron microscopy to demonstrate such a coupling effect. We discover that thermally perturbating delithiated LiNi0.6Mn0.2Co0.2O2 will trigger explosive nucleation and propagation of intragranular cracks in the lattice, providing us a unique opportunity to directly visualize the cracking mechanism and dynamics. We reveal that thermal stress associated with electrochemically induced phase inhomogeneity and internal pressure resulting from oxygen release are the primary driving forces for intragranular cracking that resembles a “popcorn” fracture mechanism. The present work reveals that, for battery performance, the intricate coupling of electrochemical, thermal, and mechanical effects will surpass the superposition of individual effects.

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Section: Resultsmentioning

confidence: 99%

Coupling of electrochemically triggered thermal and mechanical effects to aggravate failure in a layered cathode

et al. 2018

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“…The presence of additional rhombohedral phases was also verified by XAS. In contrast to the widely reported core-shell structures, [91,172,177,178] Zhang et al [179] showed that the formation of rock-salt and spinellike phases also occurs in the bulk of Ni-rich layered transition metal oxides, leading to formation of an "anti-core-shell" structure. Figure 7 presents a schematic illustration of the oxidation/ reduction processes occurring in the NCA particles.…”

Section: Crystallographic and Electronic Fatigue Of Ni-rich Layered Omentioning

confidence: 89%

Chemical, Structural, and Electronic Aspects of Formation and Degradation Behavior on Different Length Scales of Ni‐Rich NCM and Li‐Rich HE‐NCM Cathode Materials in Li‐Ion Batteries

et al. 2019

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costs are required. Current state-of-theart LIBs using, e.g., well-established LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM111) cathode material are yet not able to fulfill all these demands. In order to increase the energy density of LIBs, battery produ cers and researchers pursue various strategies. Substitution of expensive Co by Ni to achieve LiNi 1−x−y Co x Mn y O 2 compounds with x < 0.3 in order to increase the structural stability at high state-of-charge (SOC) is one possible approach. Another promising material class is represented by Li-rich high-energy NCM (HE-NCM) materials (cLi 2 MnO 3 ⋅[1 − c]LiTMO 2 [TM = Ni, Co, Mn, etc.]). All of these subgroups of layered oxides have in common a crystal structure that is prone to irreversible changes and fatigue during continuous Li (de-)intercalation. The relevant changes in electronic and crystal structure strongly depend on the particular cathode composition and micro/nanostructure. The development of a target-oriented roadmap to improved LIBs that meet the above requirements must address the underlying mechanisms on different cell levels, i.e., from the atomic level to the electrode level. A comprehensive summary of the properties and developments in the field of Ni-rich NCM [1][2][3][4][5][6][7][8][9] and Li-rich HE-NCM [10][11][12][13][14][15][16] has been presented recently In order to satisfy the energy demands of the electromobility market, both Ni-rich and Li-rich layered oxides of NCM type are receiving much attention as high-energy-density cathode materials for application in Li-ion batteries. However, due to different stability issues, their longevity is limited. During formation and continuous cycling, especially the electronic and crystal structure suffers from various changes, eventually leading to fatigue and mechanical degradation. In recent years, comprehensive battery research has been conducted at Karlsruhe Institute of Technology, mainly aiming at better understanding the primary degradation processes occurring in these layered transition metal oxides. The characteristic process of formation and mechanisms of fatigue are fundamentally characterized and the effect of chemical composition on cell chemistry, electrochemistry, and cycling stability is addressed on different length scales by use of state-of-the-art analytical techniques, ranging from "standard" characterization tools to combinations of advanced in situ and operando methods. Here, the results are presented and discussed within a broader scientific context. by several authors. Here, we focus on the detailed characterization of these materials on different length scales, including the processes during formation and fatigue.After a brief introduction of the different materials addressed here, their characteristic process of formation and mechanisms of fatigue are discussed with respect to cell chemistry, electrochemistry, and cycling stability. Based on the fundamental results of our experimental studies on the material level, the effect of formation and fatigue on different cell levels is evalu...

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“…[66,67] Experiments have found that Li x MnO 2 is particularly susceptible to transformations to spinel (see Section 3.1.3). [129] [66,67] Surface reconstructions are not only controlled by the cathode material itself, they are also strongly coupled to the environmental conditions and interactions with the electrolyte.…”

Section: Wwwadvancedsciencenewscommentioning

confidence: 99%

Narrowing the Gap between Theoretical and Practical Capacities in Li‐Ion Layered Oxide Cathode Materials

Radin

Sina

et al. 2017

Advanced Energy Materials

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491

566

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Although layered lithium oxides have become the cathode of choice for state‐of‐the‐art Li‐ion batteries, substantial gaps remain between the practical and theoretical energy densities. With the aim of supporting efforts to close this gap, this work reviews the fundamental operating mechanisms and challenges of Li intercalation in layered oxides, contrasts how these challenges play out differently for different materials (with emphasis on Ni–Co–Al (NCA) and Ni–Mn–Co (NMC) alloys), and summarizes the extensive corpus of modifications and extensions to the layered lithium oxides. Particular emphasis is given to the fundamental mechanisms behind the operation and degradation of layered intercalation electrode materials as well as novel modifications and extensions, including Na‐ion and cation‐disordered materials.

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Tuning the Activity of Oxygen in LiNi_0.8Co_0.15Al_0.05O₂ Battery Electrodes

Cited by 57 publications

References 43 publications

Coupling of electrochemically triggered thermal and mechanical effects to aggravate failure in a layered cathode

Coupling of electrochemically triggered thermal and mechanical effects to aggravate failure in a layered cathode

Chemical, Structural, and Electronic Aspects of Formation and Degradation Behavior on Different Length Scales of Ni‐Rich NCM and Li‐Rich HE‐NCM Cathode Materials in Li‐Ion Batteries

Narrowing the Gap between Theoretical and Practical Capacities in Li‐Ion Layered Oxide Cathode Materials

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