Electrochemical Surface Stress Development during CO and NO Oxidation on Pt

Ha, Yeyoung; Zeng, Zhenhua; Cohen, Yair; Greeley, Jeffrey; Gewirth, Andrew A.

doi:10.1021/acs.jpcc.6b00697

Cited by 22 publications

(30 citation statements)

References 87 publications

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“…For AIMD simulations, as we are mainly interested in the structures of local energy minima, which are less sensitive to the thickness than are the energetics themselves (see Supporting Information), calculations are also carried out using six layer slabs. However, for some other properties, such as surface energy (see Supporting information) and surface stress, [64] thicker slabs may be required.…”

Section: Computational Detailsmentioning

confidence: 99%

Characterization of oxygenated species at water/Pt(111) interfaces from DFT energetics and XPS simulations

Zeng

Greeley

2016

Nano Energy

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Determining the atomic-scale structure of oxygenated species at water/Pt(111) interfaces under electrochemical oxygen reduction reaction (ORR) conditions has been a significant, long-term challenge for both experimentalists and theorists. Numerous techniques have elucidated important information about this system, but significant uncertainties relating to the structure and hydration state of adsorbed oxygenated species remain. To resolve some of these questions, an approach based on careful calibration of Density Functional Theory (DFT)determined energetics, as well as detailed simulation of X-ray Photoelectron Spectroscopy (XPS) signatures, is developed. The combined energetic and XPS analysis of various oxygenated species demonstrates that non-hydrated OH, which has been suggested, by analysis of O1s corelevel binding data from state-of-the-art XPS studies, to be an abundant surface species at water/Pt(111) interfaces during ORR, is in fact unlikely to exist at potentials relevant to ORR, although it might be found in other conditions. The OH is more likely present in a fully hydrated state, and the experimentally observed features can be assigned to other oxygen arrangements. This insight about the nature of OH binding at water-Pt interfaces has implications not only for the general understanding of electrified water/Pt interfaces, but also for the design of ORR catalysts with improved performance on the basis of first principles calculations.

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Section: Computational Detailsmentioning

confidence: 99%

Characterization of oxygenated species at water/Pt(111) interfaces from DFT energetics and XPS simulations

Zeng

Greeley

2016

Nano Energy

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“…Density functional theory (DFT) calculations have recently been applied to describe the physics of adsorption-driven surface stress changes in electrocatalytic systems. , Such approaches may also aid in understanding analogous lithiation- or delithation-driven surface stress changes. In combination with theoretical studies, materials characterization and structural analysis of LMO particles may provide additional insights into the surface stresses responsible for particle fracture.…”

Section: Introductionmentioning

confidence: 99%

Oriented LiMn₂O₄ Particle Fracture from Delithiation-Driven Surface Stress

Warburton

Castro

Deshpande

et al. 2020

ACS Appl. Mater. Interfaces

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The insertion and removal of Li + ions into Li-ion battery electrodes can lead to severe mechanical fatigue because of the repeated expansion and compression of the host lattice during electrochemical cycling. In particular, the lithium manganese oxide spinel (LiMn 2 O 4 , LMO) experiences a significant surface stress contribution to electrode chemomechanics upon delithiation that is asynchronous with the potentials where bulk phase transitions occur. In this work, we probe the stress evolution and resulting mechanical fracture from LMO delithation using an integrated approach consisting of cyclic voltammetry, electron microscopy, and density functional theory (DFT) calculations. High-rate electrochemical cycling is used to exacerbate the mechanical deficiencies of the LMO electrode and demonstrates that mechanical degradation leads to slowing of delithiation and lithiation kinetics. These observations are further supported through the identification of significant fracturing in LMO using scanning electron microscopy. DFT calculations are used to model the mechanical response of LMO surfaces to electrochemical delithiation and suggest that particle fracture is unlikely in the [001] direction because of tensile stresses from delithiation near the (001) surface. Transmission electron microscopy and electron backscatter diffraction of the as-cycled LMO particles further support the computational analyses, indicating that particle fracture instead tends to preferentially occur along the {111} planes. This joint computational and experimental analysis provides molecularlevel details of the chemomechanical response of the LMO electrode to electrochemical delithiation and how surface stresses may lead to particle fracture in Li-ion battery electrodes.

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“…We note that a similar effect has been found in our previous calculations of structures formed by stepped Pt(221) surfaces. 45 Comparing the surface stresses of clean Mg surfaces and that of the oxide surface, the MgO(001) surface exhibits more tensile surface stress, 3.28 N/m, than those of the clean Mg surfaces (1.05 N/m for Mg(0001) surface and 0.26 N/m for Mg(1010) surface). The larger tensile surface stress of the MgO(001) can be correlated to the stronger Mg-O binding compared to the Mg-Mg bonds on the metal surface.…”

Section: Mg(0001) Mg(1010) and Mgo(001)-mentioning

confidence: 99%

Dynamic Surface Stress Response during Reversible Mg Electrodeposition and Stripping

Ha¹,

Zeng²,

Barile³

et al. 2016

J. Electrochem. Soc.

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Through the use of in situ electrochemical surface stress measurements, Mg deposition and stripping processes in electrolytes for Mg batteries are studied. We examine four electrolytes: PhMgCl+AlCl 3 /THF, (DTBP)MgCl-MgCl 2 /THF, MgCl 2 +AlCl 3 /THF, and Mg(BH 4 ) 2 +LiBH 4 /diglyme. Each of these electrolytes exhibits common surface stress response features, indicating that the mechanisms of Mg deposition and stripping are similar among the different electrolytes. Combining the measurements with density functional theory calculations, each part of the stress-potential curve is assigned to steps in the deposition and stripping reactions. The analysis suggests the following mechanism: (1) Mg 2+ /anion/solvent complexes adsorb on the substrate prior to the deposition; (2) Mg deposits as random nuclei and the deposition continues without a recrystallization process; (3) during the initial stage of Mg stripping, less coordinated Mg(0) is converted to soluble Mg(II) species and to partially oxidized species, MgO x ; (4) as the anodic reactions proceed further, Mg continues to dissolve and MgO x is removed via chemical processes; (5) due to the strong interaction between Mg and the noble metal substrate atoms, the Mg layer directly bound to the substrate are the last to be anodically converted (and desorb There is much interest in developing rechargeable Mg batteries due to the high theoretical volumetric capacity, abundance, and benign nature of Mg. Finding a suitable electrolyte for reversible Mg deposition and dissolution, however, is challenging due to the difficulty in producing soluble Mg 2+ and the formation of passivation films on the electrode surface.1-3 The first reversible Mg deposition and stripping was performed in Grignard solutions, 4-6 which suffer from low anodic stability and poor ionic conductivity. The anodic stability and the Coulombic efficiency is greatly enhanced in electrolytes based on Mg organohaloaluminate, prepared via an acid-base reaction between a MgR 2 Lewis base and an AlCl 3-n R n Lewis acid. 7 An inorganic magnesium aluminum chloride complex from MgCl 2 -and AlCl 3 -based electrolyte exhibits even higher anodic stability and a lower overpotential. 8,9 However, the corrosivity of chloride and the reactivity of Lewis acids have prompted the development of newer, less corrosive electrolytes, including Mg(BH 4 ) 2 based inorganic salts with LiBH 4 additive electrolytes 10,11 and all-magnesium phenolatebased electrolytes.12 Thus, previous work illustrates that several Mg systems exhibit promise as a battery electrolyte; however, their interfacial chemistries are complicated and need to be better understood. [8][9][10][11][12][13] Efficient electrodeposition and stripping reactions are essentials in rechargeable batteries. One of the effective in operando techniques for studying such processes is monitoring the electrochemical surface stresses developed during the deposition and dissolution of metals.14 In situ surface stress measurements are experimentally less demanding compared to oth...

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Electrochemical Surface Stress Development during CO and NO Oxidation on Pt

Cited by 22 publications

References 87 publications

Characterization of oxygenated species at water/Pt(111) interfaces from DFT energetics and XPS simulations

Characterization of oxygenated species at water/Pt(111) interfaces from DFT energetics and XPS simulations

Oriented LiMn₂O₄ Particle Fracture from Delithiation-Driven Surface Stress

Dynamic Surface Stress Response during Reversible Mg Electrodeposition and Stripping

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Electrochemical Surface Stress Development during CO and NO Oxidation on Pt

Cited by 22 publications

References 87 publications

Characterization of oxygenated species at water/Pt(111) interfaces from DFT energetics and XPS simulations

Characterization of oxygenated species at water/Pt(111) interfaces from DFT energetics and XPS simulations

Oriented LiMn2O4 Particle Fracture from Delithiation-Driven Surface Stress

Dynamic Surface Stress Response during Reversible Mg Electrodeposition and Stripping

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Oriented LiMn₂O₄ Particle Fracture from Delithiation-Driven Surface Stress