Excess‐Li Localization Triggers Chemical Irreversibility in Li‐ and Mn‐Rich Layered Oxides

Hwang, Jaeseong; Myeong, Seungjun; Jin, Wooyoung; Jang, Haeseong; Nam, Gyutae; Yoon, Moonsu; Kim, Su Hwan; Joo, Se Hun; Kwak, Sang Kyu; Kim, Min; Cho, Jaephil

doi:10.1002/adma.202001944

Cited by 48 publications

(34 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[6] Given that LMRs with a high S-to-V ratio lack material competitiveness and practical feasibility, lowering the S-to-V ratio is a straightforward solution to the impracticality of LMRs. [8] Unfortunately, LMRs with a low S-to-V ratio (i.e., particle size > 500 nm) show significant irreversibility (e.g., reversible capacity < 210 mAh g −1 ), [9] where the origin of this irreversibility has not been sufficiently identified to date. In this regard, our previous study demonstrated that "excess-Li localization in the LMR structure" attenuated the local covalency in transitionmetal-oxygen (TM-O) frameworks, facilitating "lattice-oxygen evolution", with the resulting local structural breakdown into oxygen-deficient phases triggering "overall chemical irreversibility".…”

Section: Introductionmentioning

confidence: 99%

“…In this regard, our previous study demonstrated that "excess-Li localization in the LMR structure" attenuated the local covalency in transitionmetal-oxygen (TM-O) frameworks, facilitating "lattice-oxygen evolution", with the resulting local structural breakdown into oxygen-deficient phases triggering "overall chemical irreversibility". [8] Based on this material understanding, the significant irreversibility in LMRs can possibly be alleviated by modifying the excess-Li distribution; thus, "excess-Li delocalization (i.e., the mitigation of excess-Li localization) in LMRs with a low S-to-V ratio" is expected to be a problem-solving morphological and structural design for satisfying industrial needs with high chemical reversibility (Figure 1a).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Lattice‐Oxygen‐Stabilized Li‐ and Mn‐Rich Cathodes with Sub‐Micrometer Particles by Modifying the Excess‐Li Distribution

et al. 2021

Self Cite

View full text Add to dashboard Cite

In recent years, Li‐ and Mn‐rich layered oxides (LMRs) have been vigorously explored as promising cathodes for next‐generation, Li‐ion batteries due to their high specific energy. Nevertheless, their actual implementation is still far from a reality since the trade‐off relationship between the particle size and chemical reversibility prevents LMRs from achieving a satisfactory, industrial energy density. To solve this material dilemma, herein, a novel morphological and structural design is introduced to Li1.11Mn0.49Ni0.29Co0.11O2, reporting a sub‐micrometer‐level LMR with a relatively delocalized, excess‐Li system. This system exhibits an ultrahigh energy density of 2880 Wh L−1 and a long‐lasting cycle retention of 83.1% after the 100th cycle for 45 °C full‐cell cycling, despite its practical electrode conditions. This outstanding electrochemical performance is a result of greater lattice‐oxygen stability in the delocalized excess‐Li system because of the low amount of highly oxidized oxygen ions. Geometric dispersion of the labile oxygen ions effectively suppresses oxygen evolution from the lattice when delithiated, eradicating the rapid energy degradation in a practical cell system.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lattice‐Oxygen‐Stabilized Li‐ and Mn‐Rich Cathodes with Sub‐Micrometer Particles by Modifying the Excess‐Li Distribution

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Armstrong et al [9] claimed that the capacity loss in the Li-rich layered oxides roots in the irreversible oxygen evolution and the associated deterioration of the surface structure. Cho et al [12] attributed the immoderate oxygen oxidation to the localized LiMn 6 (excess-Li localization) domains; they weaken the TM-O covalency and stability, leading to overall chemical irreversibility. Moreover, it was reported that the oxygen oxidation in the bulk results in more capacity loss than the oxygen release does on the particle surface.…”

mentioning

confidence: 99%

Stacking Faults Hinder Lithium Insertion in Li₂RuO₃

Han

Liu

Shen

et al. 2020

Advanced Energy Materials

View full text Add to dashboard Cite

Both the lithium-stoichiometric transition metal (TM) layered oxides (LiTMO 2) and the Li-rich layered oxides (Li 1+x TM 1−x O 2) cathode materials are promising highenergy cathode materials but suffer from severe initial capacity losses. [2] In addition to the electrolyte decomposition, the irreversible TM migration into the Li layer is the most commonly blamed origin for the capacity loss. It results in surface densification and triggers the layered to rock-salt structural degradation in the nickel-rich LiTMO 2 [3] or the (sub)surface deterioration such as layered to spinel(-like) structural transition [4] and a cation-mixed layered structure in Li 1+x TM 1−x O 2. [5] The anions (O 2−) are oxidized to compensate for the lost charges when more than half of the lithium ions are extracted from the layered LiTMO 2 [6] or when the Lirich Mn-based layered oxides are charged to 4.5 V (vs. Li + /Li) or above. [7] A moderate anionic redox can induce TM migration and deteriorate the lithiation dynamics of the Li-rich layered oxides, [8] whereas an immoderate one may result in oxygen loss and severe structural degradation. [9] For Layered transition metal (TM) oxides have aroused enormous interest in both fundamental and applied cathode material research in the context of high energydensity batteries. Although various mechanisms have been proposed to explain their significant initial capacity losses, the effect of the local structural defects on performance has been largely ignored. Herein, the stacking faults are visualized and their presence is correlated with the incomplete phase transition in Li 2 RuO 3 to understand the significant abnormal capacity loss in the first cycle. The comprehensive performance evaluation, physical characterization and theoretical calculations indicate that the two types of stacking faults, the [100]//[110] boundaries and the [110]//[110] boundaries, lead to sluggish lithium diffusion and increasing stacking faults deteriorates the lithium insertion dynamics. These findings are helpful to understand the performance degradation of the layer-structured oxides in which the anionic redox or the transition metal migration is not involved in electrochemical reactions. It is hoped that this research will also inspire new ideas for designing novel cathode materials and for improving the performance of existing materials by tuning the local structures or minimizing the local structural defects.

show abstract

“…Hwang et al . [ 132 ] used Operando fine‐interval X‐ray absorption spectroscopy near‐edge structure to observe changes in the electronic structure of each TM. Li 1.15 Mn 0.51 Co 0.17 Ni 0.17 O 2 with localized and delocalized excess‐ Li in its lattice system, was named L‐LMR and D‐LMR, respectively.…”

Section: Advanced Characterization Measurementmentioning

confidence: 99%

Section: Advanced Characterization Measurementmentioning

confidence: 99%

Interfacial Degradation and Optimization of Li‐rich Cathode Materials^†

Zhao

Lai

et al. 2021

Chin. J. Chem.

View full text Add to dashboard Cite

High‐energy and safe lithium ion batteries (LIBs) are in increasing need as the rapid development of electronic devices, electric vehicles, as well as energy storage station. Li‐rich oxides have attracted a lot of attention due to their high capacity and low cost as cathode material for LIBs. However, they still suffer from the vulnerable cathode/ electrolyte interface, which presents the huge challenges of surface degradation and gas release, particularly at high state of charge. Some issues of Li‐rich cathode materials, such as moderate cycle stability and voltage decay, are in tight connection with electrode‐electrolyte interfacial side reactions. Research in the area of interfacial degradation mechanism and optimization strategies is of great significance as for Li‐rich cathode, and extensive efforts have been poured. This review aims to understand the degradation mechanism of Li‐rich cathode materials, and summarize the corresponding valuable and effective optimization strategies. Based on these considerations, we also have discussed the remaining challenges and the future research direction.

show abstract

Excess‐Li Localization Triggers Chemical Irreversibility in Li‐ and Mn‐Rich Layered Oxides

Cited by 48 publications

References 44 publications

Lattice‐Oxygen‐Stabilized Li‐ and Mn‐Rich Cathodes with Sub‐Micrometer Particles by Modifying the Excess‐Li Distribution

Lattice‐Oxygen‐Stabilized Li‐ and Mn‐Rich Cathodes with Sub‐Micrometer Particles by Modifying the Excess‐Li Distribution

Stacking Faults Hinder Lithium Insertion in Li₂RuO₃

Interfacial Degradation and Optimization of Li‐rich Cathode Materials^†

Contact Info

Product

Resources

About

Excess‐Li Localization Triggers Chemical Irreversibility in Li‐ and Mn‐Rich Layered Oxides

Cited by 48 publications

References 44 publications

Lattice‐Oxygen‐Stabilized Li‐ and Mn‐Rich Cathodes with Sub‐Micrometer Particles by Modifying the Excess‐Li Distribution

Lattice‐Oxygen‐Stabilized Li‐ and Mn‐Rich Cathodes with Sub‐Micrometer Particles by Modifying the Excess‐Li Distribution

Stacking Faults Hinder Lithium Insertion in Li2RuO3

Interfacial Degradation and Optimization of Li‐rich Cathode Materials†

Contact Info

Product

Resources

About

Stacking Faults Hinder Lithium Insertion in Li₂RuO₃

Interfacial Degradation and Optimization of Li‐rich Cathode Materials^†