Cationic-potential tuned biphasic layered cathodes for stable desodiation/sodiation

Gao, Xu; Liu, Huanqing; Chen, Hongyi; Mei, Yu; Wang, Baowei; Fang, Liang; Chen, Mingzhe; Gao, Jinqiang; Ni, Lianshan; Li, Yang; Tian, Ye; Deng, Wentao; Momen, Roya; Wei, Weifeng; Chen, Libao; Zou, Guoqiang; Hou, Hongshuai; Kang, Yong‐Mook; Ji, Xiaobo

doi:10.1016/j.scib.2022.06.024

Cited by 54 publications

(46 citation statements)

References 61 publications

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“…When the calcination temperature is 800 °C and the sodium content is in the middle (10 � x � 60), P2/O3 composite structure is formed. However, as the calcination temperature increases, the crystal structure of some samples (x = 10, 50 and 60) become single phase, which is consistent with the relationship between crystal structure and thermodynamic driving force studied by Ji et al [103] As for other samples (x = 20, 30 and 40), their cationic potential is close to the boundary of P2 and O3 phase, resulting in a still P2/O3 composite structure even at high calcination temperature. In other words, an appropriate reduction in calcination temperature can increase the inhomogeneity of cationic potential, thus forming a P2/O3 composite structure.…”

Section: Calcination Temperaturesupporting

confidence: 88%

“…Therefore, the materials with small d (cationic potential close to the dividing line) tend to form P2/O3 composite structure, which provides an idea for the design and phase regulation of P2/O3 composite materials. Furthermore, a recent study also confirms the view [103] . The study of Ji et al .…”

Section: Phase Regulationsupporting

confidence: 68%

“…Factors such as precursor, method, calcinating temperature and atmosphere can all have a significant impact on the crystal structure. The regulation of calcination temperature and calcination time can generate inhomogeneity and consequently form P2/O3 composite structure [103] . Another example is that three different crystal structure materials can be prepared by only changing the calcinating temperature and atmosphere.…”

Section: Phase Regulationmentioning

confidence: 99%

“…Furthermore, a recent study also confirms the view. [103] The study of Ji et al reveals that the formation of P2/O3 composite structure is attributed to the inhomogeneity of cationic potential caused by uneven distribution of elements at the micron scale. For the materials with a cationic potential close to the dividing line, the uneven elements distribution can easily lead to the cationic potential of particles located on both sides of the dividing line, resulting in the formation of P2/O3 composite structure.…”

Section: Cationic Potentialmentioning

confidence: 99%

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Sodium Composite Oxide Cathode Materials:Phase Regulation, Electrochemical Performance and Reaction Mechanism

Zhu

Wang

et al. 2022

Batteries & Supercaps

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The abundance of sodium resources provides the basis for the large‐scale application of sodium‐ion batteries (SIBs) in the field of energy storage. Among the cathode candidates for SIBs, oxide materials stand out because of their ease of synthesis, environmental friendliness and high capacity. According to the crystal structure, oxide cathode materials can be mainly classified as P2, P3, O3 and tunnel phases. Benefiting from the combined advantages of different phases, composite oxide cathode materials have been widely studied due to the enhanced both cycling and rate performance. In this review, we analyzed the three key issues of phase regulation, electrochemical performance and reaction mechanism based on the recent progress for composite oxide cathode materials. The composite oxide cathode materials will be one of the most competitive and attractive cathodes for SIBs.

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Section: Calcination Temperaturesupporting

confidence: 88%

Section: Phase Regulationsupporting

confidence: 68%

Section: Phase Regulationmentioning

confidence: 99%

Section: Cationic Potentialmentioning

confidence: 99%

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Sodium Composite Oxide Cathode Materials:Phase Regulation, Electrochemical Performance and Reaction Mechanism

Zhu

Wang

et al. 2022

Batteries & Supercaps

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“…Second, common cationic substitution explored so far is still not able to alleviate the structural distortion induced by Fe 4+ unless reaching a low concentration of Fe. [ 42 ] Conversely, if we expect to further extend the utilization of Fe 3+ /Fe 4+ redox, we have to find efficient ways to suppress P‐O transition or structural distortion in Fe‐rich layered compounds. In contrast to the scenario of suppressing Fe migration, improving the utilization efficiency of Fe 3+ /Fe 4+ redox in the (de)sodiation range without Fe migration seems to be more practical.…”

Section: Discussionmentioning

confidence: 99%

Origin of Fast Capacity Decay in Fe‐Mn Based Sodium Layered Oxides

Gao

Fang

Wang

et al. 2022

Adv Funct Materials

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Fe‐Mn based layered oxides are recognized as promising cathode materials for sodium‐ion batteries (SIBs) with high capacities and earth‐abundant ingredients. However, their real‐world applications are still constrained by fast capacity decay accompanied with the requirements of deeper insights into the principles behind. Herein, taking O3‐NaxFe1/2Mn1/2O2 as a classic sample, the capacity fading mechanism of Fe‐Mn based layered oxides is comprehensively investigated through combined techniques. For the first time, it is revealed that Fe migration is merely triggered after the oxidation of ≈0.3 mol Fe3+ based on solid proofs from ex situ X‐ray absorption spectroscopy and Mössbauer spectroscopy, which implies the crucial role of the accumulated structural distortion induced by Jahn–Teller active Fe4+. O3‐P3 phase transition during cycling is obviously constrained along with Fe migration as evidenced by in situ/ex situ X‐ray diffraction, well interpreting the intensified polarization and the resulting large capacity loss. More importantly, within the desodiation depth (≈80% of sodium extraction) where Fe migration is almost absent, the capacity fading is dominantly rooted in the Fe4+ activated and Mn‐dissolution aggravated surface passivation as confirmed by mass/X‐ray spectroscopies and electrochemical analysis. These renewed understandings of the fast capacity decay in Fe‐Mn based layered oxides offer clearer clues for designing desirable cathodes for SIBs.

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