Nanoscale Observation of the Electronic and Local Structures of LiCoO<sub>2</sub> Thin Film Electrode by Depth-Resolved X-ray Absorption Spectroscopy

Takamatsu, Daiko; Nakatsutsumi, Takayuki; Mori, Shinichiro; Orikasa, Yuki; Mogi, Masato; Yamashige, Hisao; Satô, Kenji; Fujimoto, Takahiro; Takanashi, Yu; Murayama, Haruno; Oishi, Masatsugu; Tanida, Hajime; Uruga, Tomoya; Arai, Hajime; Uchimoto, Yoshiharu; Ogumi, Zempachi

doi:10.1021/jz2011226

Cited by 53 publications

(60 citation statements)

References 14 publications

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“…Experimental details of the operando DR-XAS and TRF-XAS measurements have been described elsewhere. 15,17 3. Results and Discussion…”

Section: Experimental Methodsmentioning

confidence: 99%

“…23 For the uncoated-LCO, the small arc observed at 4.0 V is drastically enlarged at 4.4 V. This result indicates that an inactive layer is formed on LiCoO 2 due to surface degradation. 17 For the RT-MgO-LCO, the resistance is much greater than that of the uncoated-LCO at first. However the arc is not enlarged at 4.4 V but slightly diminishes.…”

Section: (D)mentioning

confidence: 99%

“…The three thin films were investigated via DR-XAS, which can provide local structural information with a depth resolution of 3-4 nm. 17 While the spectra collected at low-exit angles consist of signals only from the surface of the LiCoO 2 electrode due to self-absorption of fluorescence X-ray from deeper range, the spectra collected at high-exit angles include signals from both the surface and bulk. Local structural parameters, such as the interatomic distances and the Debye-Waller (DW) factors for the Co-O bonds were calculated by EXAFS analysis.…”

Section: Depth-resolved Analysis Of Local Structure Changementioning

confidence: 99%

“…Recently we have developed operando total-reflection fluorescence X-ray absorption spectroscopy (TRF-XAS) 15,16 and operando depthresolved X-ray absorption spectroscopy (DR-XAS). 17,18 TRF-XAS provides surface-sensitive information regarding the electronic structure at the electrode/electrolyte interface. 15,16 DR-XAS provides information about the electronic and local structures from the surface to the bulk at a nanometric resolution.…”

Section: Introductionmentioning

confidence: 99%

“…15,16 DR-XAS provides information about the electronic and local structures from the surface to the bulk at a nanometric resolution. 17,18 These techniques are therefore potent to probe the electronic and local structure of the active material with surface modification under battery operating condition. 19 This study aims on a comprehensive understanding of the surface coating mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Stabilization of the Electronic Structure at the Cathode/Electrolyte Interface via MgO Ultra-thin Layer during Lithium-ions Insertion/Extraction

et al. 2014

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Degradation mechanism of surface coating effects at the cathode/electrolyte interface is investigated using thinfilm model electrodes combined with operando X-ray absorption spectroscopy (XAS). MgO-coated LiCoO 2 thin-film electrodes prepared via pulsed laser deposition at room temperature and high temperature are used as model systems. The MgO coating improves the durability of the cathode during high-potential cycling. Operando total reflection fluorescence XAS reveals that initial deterioration due to reduction of Co ions at the surface of the uncoated-LiCoO 2 thin film upon electrolyte immersion is inhibited by the MgO coating. Operando depth-resolved XAS reveals that the MgO coating suppresses drastic distortions of local structure at the LiCoO 2 surface as observed in the uncoated-LiCoO 2 during charging process. The electronic and local structure changes at the electrode/ electrolyte interface for two types of surface coating morphologies are discussed.

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“…Experimental details of the operando DR-XAS and TRF-XAS measurements have been described elsewhere. 15,17 3. Results and Discussion…”

Section: Experimental Methodsmentioning

confidence: 99%

Section: (D)mentioning

confidence: 99%

Section: Depth-resolved Analysis Of Local Structure Changementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Stabilization of the Electronic Structure at the Cathode/Electrolyte Interface via MgO Ultra-thin Layer during Lithium-ions Insertion/Extraction

et al. 2014

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Lattice‐Matched Interfacial Modulation Based on Olivine Enamel‐Like Front‐Face Fabrication for High‐Voltage LiCoO₂

Yan,

Zhou,

Zheng

et al. 2023

Adv Funct Materials

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The high‐voltage induced undesirable surface passivation bilayer (cathode/electrolyte interface and cation‐densified surface phase) of LiCoO2 inevitably leads to battery degradation. Herein, a continual/uniform enamel‐like olivine layer on LiCoO2 surface is fabricated by employing a high‐speed mechanical fusion method . The enamel‐like layer suppresses interfacial side reactions by tuning EC dehydrogenation, contributing to an ultrathin and stable cathode/electrolyte interface. The strong bonding affinity between LiCoO2 and enamel‐like layer restrains both lattice oxygen loss and associated layered‐to‐spinel structural distortion. Moreover, the thermal stability of highly delithiated LiCoO2 is improved, as both the onset temperatures of layered‐to‐spinel transition and O2 evolution are simultaneously postponed. Stable operation of LiCoO2 at 4.6 V high‐voltage and 55 °C elevated temperature (both >85% capacity retention after 200 cycles) is achieved. This facile and scalable high‐speed solid‐phase coating strategy establishes a technical paradigm to enhance surface/interface stability of high‐energy‐density cathode candidates by constructing an ideal enamel‐like surface layer.

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Origin of Surface Coating Effect for MgO on LiCoO₂ to Improve the Interfacial Reaction between Electrode and Electrolyte

Orikasa

Takamatsu

Yamamoto

et al. 2014

Adv Materials Inter

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Surface coating on lithium‐ion battery cathodes improves their durability at high potentials, which is a well‐known practical application. However, the mechanism is still unclear because the coating influences the electrode/electrolyte interface at a few nanometer‐scale and direct observation of the interface under real operating conditions of a battery is challenging. This study reveals the mechanism of the surface coating effect on lithium‐ion battery cathodes by using in operando X‐ray absorption spectroscopy (XAS) on well‐defined MgO‐coated LiCoO2 thin‐film electrodes prepared via pulsed laser deposition. Total‐reflection in operando XAS measurements reveal that LiCoO2 forms a reductive phase at the interface between the uncoated‐LiCoO2 electrode and the electrolyte, while the MgO coating layer inhibits the redox process, leading to an improvement in the cycle performance of the battery. Depth‐resolved in operando XAS measurements indicate that a solid solution of the magnesium phase forms at the LiCoO2 surface upon MgO coating. Magnesium ions function as pillars to stabilize the layered structure at the interface between the LiCoO2 electrode and the electrolyte for delithiated states upon cycling at potentials.

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Nanoscale Observation of the Electronic and Local Structures of LiCoO₂ Thin Film Electrode by Depth-Resolved X-ray Absorption Spectroscopy

Cited by 53 publications

References 14 publications

Stabilization of the Electronic Structure at the Cathode/Electrolyte Interface via MgO Ultra-thin Layer during Lithium-ions Insertion/Extraction

Stabilization of the Electronic Structure at the Cathode/Electrolyte Interface via MgO Ultra-thin Layer during Lithium-ions Insertion/Extraction

Lattice‐Matched Interfacial Modulation Based on Olivine Enamel‐Like Front‐Face Fabrication for High‐Voltage LiCoO₂

Origin of Surface Coating Effect for MgO on LiCoO₂ to Improve the Interfacial Reaction between Electrode and Electrolyte

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Nanoscale Observation of the Electronic and Local Structures of LiCoO2 Thin Film Electrode by Depth-Resolved X-ray Absorption Spectroscopy

Cited by 53 publications

References 14 publications

Stabilization of the Electronic Structure at the Cathode/Electrolyte Interface via MgO Ultra-thin Layer during Lithium-ions Insertion/Extraction

Stabilization of the Electronic Structure at the Cathode/Electrolyte Interface via MgO Ultra-thin Layer during Lithium-ions Insertion/Extraction

Lattice‐Matched Interfacial Modulation Based on Olivine Enamel‐Like Front‐Face Fabrication for High‐Voltage LiCoO2

Origin of Surface Coating Effect for MgO on LiCoO2 to Improve the Interfacial Reaction between Electrode and Electrolyte

Contact Info

Product

Resources

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Nanoscale Observation of the Electronic and Local Structures of LiCoO₂ Thin Film Electrode by Depth-Resolved X-ray Absorption Spectroscopy

Lattice‐Matched Interfacial Modulation Based on Olivine Enamel‐Like Front‐Face Fabrication for High‐Voltage LiCoO₂

Origin of Surface Coating Effect for MgO on LiCoO₂ to Improve the Interfacial Reaction between Electrode and Electrolyte