Comparative study of GeO2/Ge and SiO2/Si structures on anomalous charging of oxide films upon water adsorption revealed by ambient-pressure X-ray photoelectron spectroscopy

Mori, Daisuke; Oka, Hiroshi; Hosoi, Takuji; Kawai, Kentaro; Morita, Mizuho; Crumlin, Ethan J.; Liu, Zhi; Watanabe, Heiji; Arima, Kenta

doi:10.1063/1.4962202

Cited by 13 publications

(18 citation statements)

References 43 publications

(68 reference statements)

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“…Their shape (i.e., two chemical states with E bin = 33.3 and 34.3 eV due to Sb 3+ and Sb 5+ , respectively, with Sb–S environment) supports the discussion above on the Sb 3d 5/2 spectrum. , The Ge 3d spectrum revealed a single component at E bin = 30.9 eV. The latter binding energy refers to [GeS 4 ] 4– (30.8–30.9 eV) , and is much lower than that expected for GeO 2 (32.4–32.5 eV). , Thus, the presence of oxygenated Ge is rather unlikely.…”

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confidence: 74%

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A High-Entropy Multicationic Substituted Lithium Argyrodite Superionic Solid Electrolyte

Lin

Cherkashinin

Schäfer

et al. 2022

ACS Materials Lett.

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Bulk-type solid-state batteries (SSBs) constitute a promising next-generation technology for electrochemical energy storage. However, in order for SSBs to become competitive with mature battery technologies, (electro)chemically stable, superionic solid electrolytes are much needed. Multicomponent or high-entropy lithium argyrodites have recently attracted attention for their favorable material characteristics. In the present work, we report on increasing the configurational entropy of the Li 6+a P 1−x M x S 5 I solid electrolyte system and examine how this affects the structureconductivity/stability relationships. Using electrochemical impedance spectroscopy and 7 Li pulsed field gradient nuclear magnetic resonance (NMR) spectroscopy, multicationic substitution is demonstrated to result in a very low activation energy for Li diffusion of ∼0.2 eV and a high room-temperature ionic conductivity of ∼13 mS cm −1 (for Li 6.5 [P 0.25 Si 0.25 Ge 0.25 Sb 0.25 ]S 5 I). The transport properties are rationalized from a structural perspective by means of complementary neutron powder diffraction and magic-angle spinning NMR spectroscopy measurements. The Li 6.5 [P 0.25 Si 0.25 Ge 0.25 Sb 0.25 ]S 5 I solid electrolyte was also tested in high-loading SSB cells with a Ni-rich layered oxide cathode and found by X-ray photoelectron spectroscopy to suffer from interfacial side reactions during cycling. Overall, the results of this study indicate that optimization of conductivity is equally important to optimization of stability, and compositionally complex lithium argyrodites represent a new playground for a rational design of (potentially advanced) superionic solid electrolytes.

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confidence: 74%

“…The latter binding energy refers to [GeS 4 ] 4− (30.8−30.9 eV) 42,55 and is much lower than that expected for GeO 2 (32.4−32.5 eV). 56,57 Thus, the presence of oxygenated Ge is rather unlikely.…”

mentioning

confidence: 99%

A High-Entropy Multicationic Substituted Lithium Argyrodite Superionic Solid Electrolyte

Lin

Cherkashinin

Schäfer

et al. 2022

ACS Materials Lett.

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“…While a number of APXPS studies have examined metal oxides in the presence of water vapor, − only a few have reported a sharp onset to hydroxylation on the surfaces of Fe 3 O 4 (001), Al 2 O 3 /NiAl(110), and MgO(100). , In all cases the sharp onset was observed at 10 –2 % RH. An in depth comparison of MgO(100) experiments to molecular simulations in the literature revealed mechanistic insight into the observed sharp onset in hydroxylation .…”

Section: Results and Discussionmentioning

confidence: 99%

“…Herein we investigate the surface chemistry of ZnO(101̅0) for the first time using synchrotron-based ambient pressure XPS (APXPS). APXPS provides insight into how oxide surfaces interact with water vapor at pressures in the Torr range. , APXPS has been used to investigate the interaction of water vapor with various metal oxide surfaces under ambient conditions, including TiO 2 , SiO 2 /Si(111), SiO 2 /Si(100), Cu 2 O, Al 2 O 3 , α-Fe 2 O 3 (0001), MgO(100)/Ag(100), , Fe 3 O 4 (001), FeO/Au(111), Al 2 O 3 /NiAl(110), GeO 2 /Ge(100), , LaMO 3 perovskites, , LaCeO 2 (111), LiNbO 3 , and LaFeO 3 . Herein we report on results of isobar experiments performed at two different pressures (0.07 and 0.3 Torr) and temperatures from 295 to 750 K up to a maximum RH of 2%.…”

Section: Introductionmentioning

confidence: 99%

ZnO(101̅0) Surface Hydroxylation under Ambient Water Vapor

et al. 2017

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The interaction of water vapor with a single crystal ZnO(101̅0) surface was investigated using synchrotron-based ambient pressure X-ray photoelectron spectroscopy (APXPS). Two isobaric experiments were performed at 0.3 and 0.07 Torr water vapor pressure at sample temperatures ranging from 750 to 295 K up to a maximum of 2% relative humidity (RH). Below 10 % RH the ZnO(101̅0) interface is covered with ∼0.25 monolayers of OH groups attributed to dissociation at nonstoichiometric defect sites. At ∼10 % RH there is a sharp onset in increased surface hydroxylation attributed to reaction at stoichiometric terrace sites. The surface saturates with an OH monolayer ∼0.26 nm thick and occurs in the absence of any observable molecularly bound water, suggesting the formation of a 1 × 1 dissociated monolayer structure. This is in stark contrast to ultrahigh vacuum experiments and molecular simulations that show the optimum structure is a 2 × 1 partially dissociated HO/OH monolayer. The sharp onset to terrace site hydroxylation at ∼10 % RH for ZnO(101̅0) contrasts with APXPS observations for MgO(100) which show a sharp onset at 10 % RH. A surface thermodynamic analysis reveals that this shift to lower RH for ZnO(101̅0) compared to MgO(100) is due to a more favorable Gibbs free energy for terrace site hydroxylation.

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“…Even without GO/rGO sheets, the Ge surface was etched slowly in water. This is because dissolved O 2 molecules formed germanium dioxide (GeO 2 ) that absorbs water molecules , and is water-soluble . This natural etching has a rate of 0.46 nm/h at 22 °C, which increased slightly up to 6.2 nm/h at 58 °C.…”

Section: Resultsmentioning

confidence: 99%

Catalytic Properties of Chemically Modified Graphene Sheets to Enhance Etching of Ge Surface in Water

et al. 2020

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We examined chemical etching of the Ge surface assisted by single sheets of chemically modified graphene in O2-containing water. Three types of graphene sheets were used: graphene oxide (GO), hydrazine-reduced GO (hyd-rGO), and hydrothermally treated GO in an ammonia solution (amm-rGO). amm-rGO possessing pyridinic-N atoms produced the highest etching rates of the graphene used for all water temperatures tested. We propose that graphene sheets catalyze Ge oxidation underneath the sheets and that this phenomenon probably originates from the enhanced adsorption of O2 molecules in water at local defects, such as graphene edges and carbon atoms next to pyridinic-N, in the sheets. Because O2 adsorption is the initial step of either the oxygen reduction reaction or direct oxidation, it results in the formation of soluble GeO2 at the graphene/Ge interface, leaving etched hollows under the sheets. In addition, we combined graphene-assisted chemical etching with lithography by using photoresist to fabricate a trench pattern on Ge.

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Comparative study of GeO2/Ge and SiO2/Si structures on anomalous charging of oxide films upon water adsorption revealed by ambient-pressure X-ray photoelectron spectroscopy

Cited by 13 publications

References 43 publications

A High-Entropy Multicationic Substituted Lithium Argyrodite Superionic Solid Electrolyte

A High-Entropy Multicationic Substituted Lithium Argyrodite Superionic Solid Electrolyte

ZnO(101̅0) Surface Hydroxylation under Ambient Water Vapor

Catalytic Properties of Chemically Modified Graphene Sheets to Enhance Etching of Ge Surface in Water

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