Water-induced formation of an alkali-ion dimer in cryptomelane nanorods

Cheng, Shaobo; Sharma, Vidushi; Poyraz, Altuğ S.; Li, Xing; Marschilok, Amy C.; Takeuchi, Esther S.; Takeuchi, Kenneth J.; Fernández-Serra, Mariví; Zhu, Yimei

doi:10.1039/d0sc01517b

Cited by 3 publications

(2 citation statements)

References 31 publications

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“…At y = 0.125, the first molecule adsorbed molecularly at the Zn site. The additional H 2 O molecule occupies the 2b site of the neighboring empty 2 × 2 tunnel with y increasing to 0.25, as observed previously. , In both cases, the tunnel remains. At y = 0.375, the added H 2 O favors to share the same 2 × 2 tunnel with the initial H 2 O molecule at y = 0.125, thereby generating a large electrostatic repulsion within the tunnel.…”

Section: Resultssupporting

confidence: 77%

Discharging Behavior of Hollandite α-MnO₂ in a Hydrated Zinc-Ion Battery

Sadique

Housel

et al. 2021

ACS Appl. Mater. Interfaces

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Hollandite, α-MnO2, is of interest as a prospective cathode material for hydrated zinc-ion batteries (ZIBs); however, the mechanistic understanding of the discharge process remains limited. Herein, a systematic study on the initial discharge of an α-MnO2 cathode under a hydrated environment was reported using density functional theory (DFT) in combination with complementary experiments, where the DFT predictions well described the experimental measurements on discharge voltages and manganese oxidation states. According to the DFT calculations, both protons (H+) and zinc ions (Zn2+) contribute to the discharging potentials of α-MnO2 observed experimentally, where the presence of water plays an essential role during the process. This study provides valuable insights into the mechanistic understanding of the discharge of α-MnO2 in hydrated ZIBs, emphasizing the crucial interplay among the H2O molecules, the intercalated Zn2+ or H+ ions, and the Mn4+ ions on the tunnel wall to enhance the stability of discharged states and, thus, the electrochemical performances in hydrated ZIBs.

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Section: Resultssupporting

confidence: 77%

Discharging Behavior of Hollandite α-MnO₂ in a Hydrated Zinc-Ion Battery

Sadique

Housel

et al. 2021

ACS Appl. Mater. Interfaces

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“…Frequently (aqueous) solvated semiconductor surfaces sustain and enhance the formation of such networks 11,[26][27][28][29] , resulting in the ordered formation of surface chains of water molecules. Thus the very welldeveloped network of H-bonds in water plays a fundamental role in not only defining its structural and dynam-ical properties, but also the properties of the material it interacts with 30,31 .…”

Section: Introductionmentioning

confidence: 99%

Proton-transfer dynamics in ionized water chains using real-time Time Dependent Density Functional Theory

Sharma,

Fernández-Serra

2020

Preprint

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In density functional-theoretic studies of photoionized water-based systems, the role of charge localization in proton-transfer dynamics is not well understood. This is due to the inherent complexity in extracting the contributions of coupled electron-nuclear non-adiabatic dynamics in the presence of exchange and correlation functional errors. In this work, we address this problem by simulating a model system of ionized linear H-bonded water clusters using real-time Time Dependent Density Functional Theory (rt-TDDFT)-based Ehrenfest dynamics. Our aim is to understand how selfinteraction error in semilocal exchange and correlation functionals affects the probability of proton transfer. In particular, we show that for H-bonded (H2O) + n chains (with n > 3), the proton-transfer probability attains a maximum, becoming comparable to that predicted by hybrid functionals. This is because the formation of hemibonded-type geometries is largely suppressed in extended H-bonded structures. We also show how the degree of localization of the initial photo-hole is connected to the probability of a proton-transfer reaction, as well as to the separation between electronic and nuclear charge. These results are compared to those obtained with adiabatic dynamics where the initial wavefunction is allowed to relax to the ground state of the ion cluster, explaining why different functionals and dynamical approaches lead to quantitatively different results.

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Proton-transfer dynamics in ionized water chains using real-time time-dependent density functional theory

Sharma

Fernández-Serra

2020

Phys. Rev. Research

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In density functional-theoretic studies of photoionized water-based systems, the role of charge localization in proton-transfer dynamics is not well understood. This is due to the inherent complexity in extracting the contributions of coupled electron-nuclear nonadiabatic dynamics in the presence of exchange and correlation functional errors. In this work we address this problem by simulating a model system of ionized linear Hbonded water clusters using real-time time-dependent density functional theory-based Ehrenfest dynamics. Our aim is to understand how self-interaction error in semilocal exchange and correlation functionals affects the probability of proton transfer. In particular, we show that the proton-transfer probability is largely underestimated for short H-bonded chains but becomes comparable to that predicted by hybrid functionals for (H 2 O) + n chains with n > 3. This is because the formation of hemibonded-type geometries is largely suppressed in extended H-bonded structures. We also show how the degree of localization of the initial photo-hole is connected to the probability of a proton-transfer reaction, as well as to the hole-proton separation. These results are compared to those obtained with adiabatic dynamics where the initial wave function is allowed to relax to the ground state of the ion cluster, explaining why different functionals and dynamical approaches lead to quantitatively different results.

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Water-induced formation of an alkali-ion dimer in cryptomelane nanorods

Abstract:
Water displaces potassium ions and initiates the formation of a homonuclear dimer ion (K²⁺) in the tunnels of hollandite.

Cited by 3 publications

References 31 publications

Discharging Behavior of Hollandite α-MnO₂ in a Hydrated Zinc-Ion Battery

Discharging Behavior of Hollandite α-MnO₂ in a Hydrated Zinc-Ion Battery

Proton-transfer dynamics in ionized water chains using real-time Time Dependent Density Functional Theory

Proton-transfer dynamics in ionized water chains using real-time time-dependent density functional theory

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Water-induced formation of an alkali-ion dimer in cryptomelane nanorods

Abstract: Water displaces potassium ions and initiates the formation of a homonuclear dimer ion (K2+) in the tunnels of hollandite.

Cited by 3 publications

References 31 publications

Discharging Behavior of Hollandite α-MnO2 in a Hydrated Zinc-Ion Battery

Discharging Behavior of Hollandite α-MnO2 in a Hydrated Zinc-Ion Battery

Proton-transfer dynamics in ionized water chains using real-time Time Dependent Density Functional Theory

Proton-transfer dynamics in ionized water chains using real-time time-dependent density functional theory

Contact Info

Product

Resources

About

Abstract:
Water displaces potassium ions and initiates the formation of a homonuclear dimer ion (K²⁺) in the tunnels of hollandite.

Discharging Behavior of Hollandite α-MnO₂ in a Hydrated Zinc-Ion Battery

Discharging Behavior of Hollandite α-MnO₂ in a Hydrated Zinc-Ion Battery