Screening based approach and dehydrogenation kinetics for MgH2: Guide to find suitable dopant using first-principles approach

Kumar, E. Mathan; Rajkamal, Anand; Thapa, Ranjit

doi:10.1038/s41598-017-15694-x

Cited by 27 publications

(19 citation statements)

References 41 publications

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“…we computed the energy needed to substitute one Nb at a Mg site. It is 1.88 eV, similar to values reported by Kumar et al49 It can be seen inFigure 2that a substitutional Nb atom located at a Mg atom position produces a small local non-symmetrical distortion in the structure, where the most affected atoms are the near neighbors to Nb atom.This geometric rearrangement is a consequence of charge redistribution and different atomic…”

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confidence: 86%

Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations

et al. 2018

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In the present work we considered the effect of Nb and charged vacancies in the properties of magnesium hydride. We performed spin polarized ab initio calculations substituting a Mg atom by a Nb impurity. Then some charged vacancies were included in the MgH 2 +Nb system (V H , V Mg or V Mg-H). In each case three possible charge states were considered (+1, 0 or-1). We computed cohesion and formation energy, bandgap and magnetic moment. We also calculate the transition level energy value and the density of states. Nb states are located in the gap, and a magnetic moment is induced. In the case of the system with charged vacancies we found that the V H + and V H 0 are the more probable formed and the states near the Fermi level (E F) are filled thus getting an important reduction in the bandgap.

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confidence: 86%

Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations

et al. 2018

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“…Magnesium hydrogen (MgH 2 ) light element complex hydrides are considered to be the most promising materials for hydrogen storage . Kumar et al investigated the thermodynamics and kinetics of the bulk and (110) surface of MgH 2 systems with three different types of dopants (neutral, n‐type, and transition metal) using density functional theory (DFT)‐based calculations . H 2 desorption (from surface) barrier energy at the outer two doping layers of MgH 2 (110) showed a significant decrease, whereas doping had no impact on the barrier energy of the third layer.…”

Section: Rational Design Of Anode Materialsmentioning

confidence: 99%

“…A summary of effective methods to enhance the Ni–MH battery cyclability was also provided. Hu et al used the hydrogen adsorption–desorption properties improved Co‐free, cost‐efficient La 2 MgNi 9 alloy as the negative electrode and a sintered Ni electrode as the positive electrode to construct a small prototype Ni–MH cell . The initial discharge capacity of the cell was 760 mAh at 0.2 C, which declined by only 13% after 300 cycles.…”

Section: Device Designmentioning

confidence: 99%

Recent Advances in Rational Electrode Designs for High‐Performance Alkaline Rechargeable Batteries

Huang

Niu

et al. 2019

Adv Funct Materials

160

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In recent years, noticeable progress is achieved regarding alkaline rechargeable batteries (ARBs). Due to their merits of safety and low cost, ARBs are considered promising energy storage sources for large-scale grid energy storage, electric vehicles, and hybrid electric vehicles, as well as wearable and portable devices. While previous reviews have focused on specific topics associated with ARBs, providing a comprehensive review on rechargeable alkaline batteries is both timely and worthwhile. In this review, the recent progress in ARBs is summarized and the strategies underlying rational electrode designs for cathodes and anodes are highlighted, as well as their applications in full cells including flexible batteries. This review may pave the way for further designs of high-performance alkaline batteries. and a LiMn 2 O 4 cathode in 1994. [10] However, the electrolyzation of H 2 O limits the operating voltage window of ARABs, which are stable within ≈1.23 V. Furthermore, the electrode materials should be selected so that they avoid the electrolysis of H 2 O and maintain chemical stability in H 2 O. [3a] However, the preferred LIB cathodes, such as LiCoO 2 , LiMn 2 O 4 , and LiFePO 4 , which display a reversible capacity of 140, [11] 120, [12] and 170 mAh g −1 , [13] respectively, exhibit narrow working potentials and high stability in aqueous solutions but can take part in one-electron reactions at most. In addition, promising anode materials, such as VO 2 , [14] V 2 O 5 , [15] and H 2 V 3 O 8 , [16] possess the theoretical capacity or show the highest reversible capacity of only 161.6, 200, and 234 mAh g −1 , respectively, [3a] thereby leading to a full cell with a low energy density under the limited operating voltage window in aqueous electrolytes. Although the so-called "water-in-salt" electrolyte and its many variations can enable aqueous batteries with an electrochemical stability window of >3.0 V and an energy density of 200 Wh kg −1 , respectively, the ultrahighly concentrated electrolyte makes the cost too high for practical applications. [17] Since the early 20th century, alkaline rechargeable batteries (ARBs) based on nickel-iron (Ni-Fe) and nickel-cadmium (Ni-Cd) have been established and developed by Jüngner and Edison. [18] These batteries, which use alkaline solution as electrolytes, undergo an entirely different storage mechanism from ARABs and involve H + insertion/extraction and conversion processes from the alkali-metal ion insertion/extraction. Take the reaction mechanism of Ni-Fe batteries as an example

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“…[36] and −53.85 kJ/mol·H 2 in Ref. [38]. At the same time, we estimated the decomposition temperature according to the following relationship: ln P P 0 = ∆H RT − ∆S R , where P, P 0 , R, T, and ∆S represent the pressure, the standard pressure, the gas constant, the decomposition temperature, and the entropy change, respectively.…”

Section: Resultsmentioning

confidence: 99%

Stability, Electronic Structure, and Dehydrogenation Properties of Pristine and Doped 2D MgH2 by the First Principles Study

Shao

2018

Metals

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Based on first principles calculations, we theoretically predict the new two-dimensional (2D) MgH 2 . The thermodynamic stability, partial density of states, electron localization function, and Bader charge of pure and the transition metal (Ti, V, and Mn) doped 2D MgH 2 are investigated. The results show that all the systems are dynamically stable, and the dehydrogenation properties indicate that the decomposition temperature can be reduced by introducing the transition metal, and the Mn doped system exhibits good performance for better hydrogen storage and dehydrogenation kinetics. 482 2 of 10 phonon spectra and heat of formation. The calculated heat of formation for pure and Ti/V/Mn doped 2D MgH 2 are −37.57, −25.67, −18.14, and −23.90 kJ/mol·H 2 , respectively, which are significantly lower than that of −75.99 kJ/mol·H 2 of bulk MgH 2 . The electronic structure and hydrogen desorption kinetics results show that the predicted two-dimensional magnesium hydride are promising candidates for hydrogen storage. Computational DetailsThe structural optimization and electronic property calculations were performed using the projector augmented plane-wave method (PAW) based on the density functional theory (DFT) in the Vienna ab initio simulation package (VASP) [18,19]. The exchange-correlation potential was approximated by generalized gradient approximation (GGA) in the Perdew-Burke-Ernzerhof (PBE) form [20,21]. To avoid the interlayer effects of the c-axis, the vacuum region around 15 Å was set in all the systems. The energy cutoff of 600 eV and the 9 × 9 × 1 Γ-centered Monkhorst-Pack k-points [22] were employed for all calculations. The atomic positions were fully relaxed and the force tolerance between each atom was less than 0.01 eV/Å for the structural optimization. The convergence criteria of 10 −6 eV per atom was applied to be self-consistent. Meanwhile, for calculation of electronic structures, we also applied the local density approximation (LDA) [23] and HSE06 [24] was functional. The kinetic stability was discussed using the phonon spectra calculations in PHONOPY code coupled with VASP using the density functional perturbation theory (DFPT) method [25][26][27]. Results and Discussion

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Screening based approach and dehydrogenation kinetics for MgH2: Guide to find suitable dopant using first-principles approach

Cited by 27 publications

References 41 publications

Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations

Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations

Recent Advances in Rational Electrode Designs for High‐Performance Alkaline Rechargeable Batteries

Stability, Electronic Structure, and Dehydrogenation Properties of Pristine and Doped 2D MgH2 by the First Principles Study

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Screening based approach and dehydrogenation kinetics for MgH2: Guide to find suitable dopant using first-principles approach

Cited by 27 publications

References 41 publications

Effects of Native Vacancies on Nb-Doped MgH2 Using Density Functional Theory Calculations

Effects of Native Vacancies on Nb-Doped MgH2 Using Density Functional Theory Calculations

Recent Advances in Rational Electrode Designs for High‐Performance Alkaline Rechargeable Batteries

Stability, Electronic Structure, and Dehydrogenation Properties of Pristine and Doped 2D MgH2 by the First Principles Study

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Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations

Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations