Correlation between thermodynamical stabilities of metal borohydrides and cation electronegativites: First-principles calculations and experiments

Nakamori, Yoshiteru; Miwa, Kenji; Ninomiya, A.; Li, Haiwen; Ohba, Nobuko; Towata, Shin‐ichi; Züttel, Andreas; Orimo, Shin Ichi

doi:10.1103/physrevb.74.045126

Cited by 487 publications

(563 citation statements)

References 47 publications

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“…As in case of the aluminium hydrides there are two different possibilities for substitution in these complex hydrides: cation substitution and anion substitution. Nakamori et al (Nakamori et al, 2006) …”

Section: Borohydridesmentioning

confidence: 99%

Thermodynamics of Metal Hydrides: Tailoring Reaction Enthalpies of Hydrogen Storage Materials

Dornheim¹

2011

Thermodynamics - Interaction Studies - Solids, Liquids and Gases

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Section: Borohydridesmentioning

confidence: 99%

Thermodynamics of Metal Hydrides: Tailoring Reaction Enthalpies of Hydrogen Storage Materials

Dornheim¹

2011

Thermodynamics - Interaction Studies - Solids, Liquids and Gases

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“…Nakamori et al [33] studied theoretically the stabi-lity of metal-borohydrides and found a correlation between the heat of formation and the Pauling electronegativity of the cation. The value reported for LiBH 4 was D f H (0 K)¼ 146 kJ mol 1 .…”

Section: Standard Enthalpy Of Formationmentioning

confidence: 99%

A thermodynamic assessment of LiBH4

Kharbachi

Pinatel

Nuta

et al. 2012

Calphad

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a b s t r a c t Thermodynamic data of the LiBH 4 compound are reviewed and critically assessed. On the basis of literature data of heat capacity, heat of formation, temperature and enthalpy of phase transitions, a CALPHAD optimized Gibbs energy function is derived for the condensed phases i.e. orthorhombic and hexagonal solid phases and the liquid phase. Considering hydrogen as an ideal gas phase, the thermodynamics of decomposition reactions of LiBH 4 is calculated, showing good agreement with existing experimental data.

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“…The ionic radii were taken from literature. [44][45][46][47] The radius of the ion with an underlined name is connected to the horizontal axis. The general trend that is observed in all three series (X + PSS − ; TBA + Y − ; TBA + Z − ) is that an increase in ion size is accompanied by a reduction in the magnitude of the work function modifi cation.…”

Section: Ion Size Effects In Wmlsmentioning

confidence: 99%

Origin of Work Function Modification by Ionic and Amine‐Based Interface Layers

Reenen

Kouijzer

Janssen

et al. 2014

Adv Materials Inter

127

136

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can evolve into a successful thin fi lm photovoltaic technology. To this end, further improvements in the sunlight-toelectricity conversion effi ciency are still needed. To do so, not only the optoelectronic, active layer should be considered, but also the connection between this layer and the electrodes. This connection is facilitated by so-called work function modifi cation layers (WMLs) that serve to align the transport levels in the organic semiconductor and the conductor by modifi cation of the work function. Materials that are often used are poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) for improving hole collection and injection in combination with an indium tin oxide (ITO) electrode and LiF for the electron contact in combination with an Al metal electrode. A new generation of WMLs fi rst introduced by Cao et al. is based on polyelectrolytes or tertiary aliphatic amines, such as poly [(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt -2,7-(9,9-dioctylfluorene)] (PFN) and the corresponding ethyl ammonium bromide. [ 1 ] Although these materials improve carrier injection or extraction in different organic diode devices, [1][2][3][4][5][6][7] the mechanism behind this improvement is not completely clear. This ambiguity hinders design, selection and optimization of new WMLs.Mechanisms that are generally considered to result in electric fi elds and concomitant work function shifts at metal-organic interfaces are doping, charge transfer, and dipole formation. [8][9][10] Regarding the work function modifi cation of amine side-groups, Lindell et al. [ 11 ] found by photoelectron spectroscopy and density functional calculations that the electron donor para-phenylenediamine chemisorbs onto atomically clean Ni in vacuum. [ 12 ] Due to partial electron transfer from the amine unit, a work function reduction of 1.55 eV is achieved, resulting in a less deep Fermi level. This explanation is not likely to hold for the technologically more relevant procedure on which we shall focus, being the deposition of WMLs from solution on a metal at atmospheric pressure: the metal is not atomically clean, which likely inhibits chemisorption. In other work by Zhou et al. [ 13 ] it is shown that the work function reduction, at atmospheric pressure, by the amine groups in poly(ethylenimine ethoxylated) (PEIE), is generally the same on different conductors. Work function modifi cation by polyelectrolytes and tertiary aliphatic amines is found to be due to the formation of a net dipole at the electrode interface, induced by interaction with its own image dipole in the electrode. In polyelectrolytes differences in size and side groups between the moving ions lead to differences in approach distance towards the surface. These differences determine magnitude and direction of the resulting dipole. In tertiary aliphatic amines the lone pairs of electrons are anticipated to shift towards their image when close to the interface rather than the nitrogen nuclei, which are sterically hindered by the alkyl side chains. ...

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Correlation between thermodynamical stabilities of metal borohydrides and cation electronegativites: First-principles calculations and experiments

Cited by 487 publications

References 47 publications

Thermodynamics of Metal Hydrides: Tailoring Reaction Enthalpies of Hydrogen Storage Materials

Thermodynamics of Metal Hydrides: Tailoring Reaction Enthalpies of Hydrogen Storage Materials

A thermodynamic assessment of LiBH4

Origin of Work Function Modification by Ionic and Amine‐Based Interface Layers

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