Charge/discharge mechanism of a new Co-doped Li 2 O cathode material for a rechargeable sealed lithium-peroxide battery analyzed by X-ray absorption spectroscopy

Ogasawara, Yasushi; Hibino, Mitsuhiro; Kobayashi, Hiroaki; Kudo, Tetsuichi; Asakura, Daisuke; Hosono, Eiji; Nagamura, Naoka; Kitada, Yoshimi; Honma, Itaru; Oshima, Masaharu; Okuoka, Shin Ichi; Ono, Hironobu; Yonehara, Koji; Sumida, Yasutaka; Mizuno, Noritaka

doi:10.1016/j.jpowsour.2015.04.050

Cited by 31 publications

(27 citation statements)

References 21 publications

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“…[42][43][44] The difference in the degree of oxygen adsorption in the interior and at the surface of the NS causes some offset of the peak position at ∼ 542.5eV, which was finally confirmed by the XPS analysis of the samples with different etching time (Figure 2d). In Figure 2d As shown in Figure 4a and b, the electrochemical performances for Co3O4 bulk and nanosheets were tested at different current density of 100, 200 and 400 mA g -1 .…”

Section: Resultsmentioning

confidence: 61%

Boosting the Electrocatalytic Activity of Co₃O₄ Nanosheets for a Li-O₂ Battery through Modulating Inner Oxygen Vacancy and Exterior Co³⁺/Co²⁺ Ratio

et al. 2017

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Rechargeable Li-O2 batteries have been considered as the most promising chemical power owing to their ultrahigh specific energy density. But the sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) result in the high overpotential (~1.5V), the poor rate capability and even the short cycle life, which critically hinder their practical applications. Herein, we propose a synergistic strategy to boost the electrocatalytic activity of Co3O4 nanosheets for Li-O2 battery by tuning the inner oxygen vacancies and the exterior Co 3+ /Co 2+ ratio which have been identified by Raman spectroscopy, X-ray photoelectron spectroscopy and X-ray Absorption Near Edge Structure spectroscopy. Operando X-ray diffraction and ex-situ Scanning Electron Microscope are used to probe the evolution of the discharge product. In comparison with bulk Co3O4, the cells catalyzed by Co3O4 nanosheets show a much higher initial capacity (~24051.2mAh g -1 ), better rate capability (8683.3mAh g -1 @400mA g -1 ) and cycling stability (150 cycles@400mA g -1 ), and lower overpotential. The large enhancement of the electrochemical performances can be greatly attributed to the synergistic effect of the architectured 2D nanosheets, the oxygen vacancies and Co 3+ /Co 2+ difference between the surface and the interior.Moreover, the addition of LiI in the electrolyte can further reduce the overpotential making the battery more practical. This study offers some insights into designing high performance electrocatalysts for Li-O2 batteries through the combination of the 2D nanosheets architecture, oxygen vacancy and surface electronic structure regulation.

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Section: Resultsmentioning

confidence: 61%

Boosting the Electrocatalytic Activity of Co₃O₄ Nanosheets for a Li-O₂ Battery through Modulating Inner Oxygen Vacancy and Exterior Co³⁺/Co²⁺ Ratio

et al. 2017

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“…Since catalysts are required to facilitate the lithium–oxygen‐battery reactions, it may be possible to activate oxygen redox in certain electrochemically inactive compounds, such as layered Li 2 TiO 3 and Li 3 NbO 4 , by doping in active metals that exhibit a catalytic effect. The example of Co‐doped Li 2 O as cathode electrode of a lithium‐peroxide battery presents a typical case where Co is utilized to catalyze the oxygen activity in insulative Li 2 O . In addtion to doping, an exterior nanocatalyzer tightly adhered to the electrodes is also feasible for activating anionic redox, as recently shown by nanolithia cathodes with nano‐Co 3 O 4 as the substrate and catalyzer …”

Section: Discussionmentioning

confidence: 99%

Anionic Redox in Rechargeable Lithium Batteries

2017

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The extraordinarily high capacities delivered by lithium-rich oxide cathodes, compared with conventional layered oxide electrodes, are a result of contributions from both cationic and anionic redox processes. This phenomenon has invoked a lot of research exploring new kinds of lithium-rich oxides with multiple-electron redox processes. Though proposed many years ago, anionic redox is now regarded to be crucial in further developing high-capacity electrodes. A basic overview of the previous work on anionic redox is given, and issues related to electronic and geometric structures are discussed, including the principles of activation, reversibility, and the energy barrier of anionic redox. Anionic redox also leads to capacity loss and structural degradation, as well as voltage hysteresis, which shows the importance of controlling anionic redox reactions. Finally, the techniques used for characterizing anionic redox processes are reviewed to aid the rational choice of techniques in future studies. Important perspectives are highlighted, which should instruct future work concerning anionic redox processes.

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“…This will trigger anionic redox activity in light TM chalcogenides, as exemplified by the cases of disordered Li 2 TiS 3 and Li 3 NbS 4 , which exhibit considerable electrochemical activities . To some extent, due to their larger U values, heavy TM ions can be applied as internal catalysts by doping to lower the thermodynamic barrier for anionic redox processes, as shown by Co‐doped Li 2 O in a lithium‐peroxide battery . More amazingly, external catalysts comprising heavy TM ions, such as nano‐Co 3 O 4 , are also available to stimulate oxygen redox activity in Li 2 O, as recently reported …”

Section: Discussionmentioning

confidence: 99%

Thermodynamic Activation of Charge Transfer in Anionic Redox Process for Li‐Ion Batteries

Jiang

Huang

et al. 2017

Adv Funct Materials

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Anionic redox processes are vital to realize high capacity in lithium-rich electrodes of lithium-ion batteries. However, the activation mechanism of these processes remains ambiguous, hampering further implementation in new electrode design. This study demonstrates that the electrochemical activity of inert cubic-Li 2 TiO 3 is triggered by Fe 3+ substitution, to afford considerable oxygen redox activity. Coupled with first principles calculations, it is found that electron holes tend to be selectively generated on oxygen ions bonded to Fe rather than Ti. Subsequently, a thermodynamic threshold is unravelled dictated by the relative values of the Coulomb and exchange interactions (U) and charge-transfer energy (Δ) for the anionic redox electron-transfer process, which is further verified by extension to inactive layered Li 2 TiS 3 , in which the sulfur redox process is activated by Co substitution to form Li 1.2 Ti 0.6 Co 0.2 S 2 . This work establishes general guidance for the design of high-capacity electrodes utilizing anionic redox processes.

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Charge/discharge mechanism of a new Co-doped Li 2 O cathode material for a rechargeable sealed lithium-peroxide battery analyzed by X-ray absorption spectroscopy

Cited by 31 publications

References 21 publications

Boosting the Electrocatalytic Activity of Co₃O₄ Nanosheets for a Li-O₂ Battery through Modulating Inner Oxygen Vacancy and Exterior Co³⁺/Co²⁺ Ratio

Boosting the Electrocatalytic Activity of Co₃O₄ Nanosheets for a Li-O₂ Battery through Modulating Inner Oxygen Vacancy and Exterior Co³⁺/Co²⁺ Ratio

Anionic Redox in Rechargeable Lithium Batteries

Thermodynamic Activation of Charge Transfer in Anionic Redox Process for Li‐Ion Batteries

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Charge/discharge mechanism of a new Co-doped Li 2 O cathode material for a rechargeable sealed lithium-peroxide battery analyzed by X-ray absorption spectroscopy

Cited by 31 publications

References 21 publications

Boosting the Electrocatalytic Activity of Co3O4 Nanosheets for a Li-O2 Battery through Modulating Inner Oxygen Vacancy and Exterior Co3+/Co2+ Ratio

Boosting the Electrocatalytic Activity of Co3O4 Nanosheets for a Li-O2 Battery through Modulating Inner Oxygen Vacancy and Exterior Co3+/Co2+ Ratio

Anionic Redox in Rechargeable Lithium Batteries

Thermodynamic Activation of Charge Transfer in Anionic Redox Process for Li‐Ion Batteries

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Product

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Boosting the Electrocatalytic Activity of Co₃O₄ Nanosheets for a Li-O₂ Battery through Modulating Inner Oxygen Vacancy and Exterior Co³⁺/Co²⁺ Ratio

Boosting the Electrocatalytic Activity of Co₃O₄ Nanosheets for a Li-O₂ Battery through Modulating Inner Oxygen Vacancy and Exterior Co³⁺/Co²⁺ Ratio