High Reversibility of Lattice Oxygen Redox Quantified by Direct Bulk Probes of Both Anionic and Cationic Redox Reactions

Dai, Kun; Wu, Jinpeng; Zhuo, Zengqing; Li, Qinghao; Sallis, Shawn; Mao, Jing; Ai, Guo; Sun, Chihang; Li, Zaiyuan; Gent, William E.; Chueh, William C.; Chuang, Yi‐De; Zeng, Rong; Shen, Zhi‐Xun; Yan, Shishen; Piper, Louis F. J.; Hussain, Zahid; Liu, Gao; Yang, Wanli

doi:10.1016/j.joule.2018.11.014

Cited by 256 publications

(419 citation statements)

References 64 publications

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“…Similar absorption and emission features are also seen in Na manganese oxides that exhibit an anomalous capacity. 16,17,58 While the appearance of localized spectroscopic features has been interpreted as the signature of O 2− /O − redox, as noted by Xu et al 31 , it is also consistent with the formation of molecular O2. 41 Similar spectroscopic features have been observed in lithium peroxide.…”

Section: Critical Analysis Of Oxygen Redoxmentioning

confidence: 74%

Manganese oxidation as the origin of the anomalous capacity of Mn-containing Li-excess cathode materials

et al. 2019

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The Li-excess manganese oxides are a candidate cathode material for the next generation of Li-ion batteries because of their ability to reversibly intercalate more Li than traditional cathode materials. While reversible oxidation of lattice oxygen has been proposed as being at the origin of this excess, anomalous capacity, questions about the underlying electrochemical reaction mechanisms remain unresolved . Here we critically analyze the oxygen redox hypothesis and explore alternative explanation s for the origin of the anomalous capacity of Li -excess manganese oxides, including the formation of peroxide ions or trapped oxygen molecules and the oxidation of Mn . Firstprinciples calculations motivated by the Li -Mn-O phase diagram show that the electrochemical behavior of the Li -excess manganese oxides is thermodynamically consistent with the oxidation of Mn from the +4 oxid ation state to the +7 oxidation state and the concomitant migration of Mn from octahedral sites to tetrahedral sites. It is shown that the Mn oxidation hypothesis is capable of explaining poorly understood electrochemical behavior of Li-excess materials, including the activation step, the voltage hysteresis, and voltage fade.

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Section: Critical Analysis Of Oxygen Redoxmentioning

confidence: 74%

Manganese oxidation as the origin of the anomalous capacity of Mn-containing Li-excess cathode materials

et al. 2019

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“…We note that such an important profile is largely missing in the conventional RIXS cuts with coarse step size of excitation energies (Figure 5(b) and (d)). Additionally, as described in Figure 4, the intensity of the oxygen-redox feature varies systematically with electrochemical cycling, which could be quantified to monitor the behavior of oxidized oxygen in battery electrodes [17]. Compared with the signal change of a single RIXS cut, quantifications by integrating the full mRIXS profile along both emission and excitation energies are desirable because of both the improved signal-to-noise ratio and completeness.…”

Section: Discussionmentioning

confidence: 99%

“…Fourth, two associated mRIXS features emerge in the charged electrodes if oxygen redox reactions are involved [8,[17][18][19]. One is a sharp feature at 523.7 eV emission and 531 eV excitation energy (Feature-5), the other is a weak feature close to the elastic line at the same excitation energy (Feature-4).…”

Section: Presentations Of O-k Mrixsmentioning

confidence: 99%

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Fingerprint Oxygen Redox Reactions in Batteries through High-Efficiency Mapping of Resonant Inelastic X-ray Scattering

Sallis

et al. 2019

Condensed Matter

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Realizing reversible reduction-oxidation (Redox) reactions of lattice oxygen in batteries is a promising way to improve the energy and power density. However, conventional oxygen absorption spectroscopy fails to distinguish the critical oxygen chemistry in oxide-based battery electrodes. Therefore, high-efficiency full-range mapping of resonant inelastic X-ray scattering (mRIXS) has been developed as a reliable probe of oxygen redox reactions. Here, based on mRIXS results collected from a series of Li1.17Ni0.21Co0.08Mn0.54O2 electrodes at different electrochemical states and its comparison with peroxides, we provide a comprehensive analysis of five components observed in the mRIXS results. While almost all the components change upon electrochemical cycling, comparison with peroxide species show that only two evolving features correspond to the critical oxidized oxygen states. One is a specific feature at 531.0eV excitation and 523.7eV emission energy, the other is a low-energy loss feature. We show that both features evolve with electrochemical cycling of Li1.17Ni0.21Co0.08Mn0.54O2 electrodes, and could be used for characterizing oxygen redox states in battery electrodes. This work is the first benchmark for a complete assignment of all the important mRIXS features collected from battery materials, which provides guidelines for future studies in characterization, analysis and theoretical calculation for probing and understanding oxygen redox reactions.

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“…[61][62][63][64][65][66] AEI Thickness, Active-Li Trapping, and Transition-Metal Dissolution: The quantification of AEI thickness, which reflects the degree of anode degradation, has been a daunting challenge due to its air sensitivity, vulnerability, and the limitation of techniques available. Initially, a "healthy" graphite AEI is featured with a thin mono-layer architecture.…”

Section: Anode Surface Chemistrymentioning

confidence: 99%

A Comprehensive Analysis of the Interphasial and Structural Evolution over Long‐Term Cycling of Ultrahigh‐Nickel Cathodes in Lithium‐Ion Batteries

Manthiram

2019

Advanced Energy Materials

144

111

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Ultrahigh‐Ni layered oxides hold great promise as high‐energy‐density cathodes at an affordable cost for lithium‐ion batteries, yet their practical application is greatly hampered by the poor cyclability. Herein, by employing LiNi0.94Co0.06O2 as a model cathode in a full‐cell configuration, the interphasial and structural evolution processes of ultrahigh‐Ni layered oxides are systematically investigated over the course of their service life (1500 cycles). By applying advanced analytic techniques (e.g., Li‐isotope labeling, region‐of‐interest method), the dynamic chemical evolution on the cathode surface is revealed with spatial resolution, and the correlation between lattice distortion and cathode surface reactivity is established. Benefiting from in situ X‐ray diffraction (XRD) analysis, the ultrahigh‐Ni layered oxide is demonstrated to undergo dual‐phase reaction mechanisms with huge lattice variation, which leads to a decrease in crystallinity and secondary particle pulverization. Furthermore, the critical impact of cathode surface reaction on the graphite anode–electrolyte interphase (AEI) is revealed at nanometer scale, and a universal chemical/physical evolution process of the AEI is illustrated, for the first time. Finally, the practical viability of ultrahigh‐Ni layered oxides is demonstrated through Al‐doping strategy. This work presents a comprehensive understanding of the structural and interphasial degradation of ultrahigh‐Ni layered oxide cathodes for developing high‐energy‐density lithium‐ion batteries.

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High Reversibility of Lattice Oxygen Redox Quantified by Direct Bulk Probes of Both Anionic and Cationic Redox Reactions

Cited by 256 publications

References 64 publications

Manganese oxidation as the origin of the anomalous capacity of Mn-containing Li-excess cathode materials

Manganese oxidation as the origin of the anomalous capacity of Mn-containing Li-excess cathode materials

Fingerprint Oxygen Redox Reactions in Batteries through High-Efficiency Mapping of Resonant Inelastic X-ray Scattering

A Comprehensive Analysis of the Interphasial and Structural Evolution over Long‐Term Cycling of Ultrahigh‐Nickel Cathodes in Lithium‐Ion Batteries

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