Enhanced Li Adsorption and Diffusion in Single‐Walled Silicon Nanotubes: An ab Initio Study

Phys. Chem. Chem. Phys.

Persson

et al. 2015

Self Cite

378

269

We systematically investigate a novel two-dimensional nanomaterial, phosphorene, as an anode for Na-ion batteries. Using first-principles calculations, we determine the Na adsorption energy, specific capacity and Na diffusion barriers on monolayer phosphorene. We examine the main trends in the electronic structure and mechanical properties as a function of Na concentration. We find a favorable Na-phosphorene interaction with a high theoretical Na storage capacity. We find that Na-phosphorene undergoes semiconductor-metal transition at high Na concentration. Our results show that Na diffusion on phosphorene is fast and anisotropic with an energy barrier of only 0.04 eV. Owing to its high capacity, good stability, excellent electrical conductivity and high Na mobility, monolayer phosphorene is a very promising anode material for Na-ion batteries. The calculated performance in terms of specific capacity and diffusion barriers is compared to other layered 2D electrode materials, such as graphene, MoS2, and polysilane.

Section: Methodsmentioning

confidence: 99%

Phosphorene as an anode material for Na-ion batteries: a first-principles study

Kulish

Phys. Chem. Chem. Phys.

Persson

et al. 2015

Self Cite

378

269

“…The initial guess of the diffusion trajectory is generated by linear interpolations between the initial and final points of the pathway. 80 The NEB method has been used successfully in the previous studies to determine Li diffusion rates in silicon structures, 16,23,25,54,66 as well as various electrode materials. 63,[67][68][69][70][71]…”

Section: Methodsmentioning

confidence: 99%

Controlling Na diffusion by rational design of Si-based layered architectures

Kulish

Phys. Chem. Chem. Phys.

et al. 2014

Self Cite

By means of density functional theory, we systematically investigate the insertion and diffusion of Na and Li in layered Si materials (polysilane and H-passivated silicene), in comparison with bulk Si. It is found that Na binding and mobility can be significantly facilitated in layered Si structures. In contrast to the Si bulk, where Na insertion is energetically unfavorable, Na storage can be achieved in polysilane and silicene. The energy barrier for Na diffusion is reduced from 1.06 eV in the Si bulk to 0.41 eV in polysilane. The improvements in binding energetics and in the activation energy for Na diffusion are attributed to the large surface area and available free volume for the large Na cation. Based on these results, we suggest that polysilane may be a promising anode material for Na-ion and Li-ion batteries with high charge-discharge rates.

“…The difference between chemical potentials of Li in anode and cathode determines the battery voltage [30]. To analyze the insertion of metal atoms into anode materials, recent studies calculated M µ as energy per metal atom in a vacuum [16,21,[35][36][37][38][39][40] or in bulk metal [41,42]. Defect formation energy calculated vs. vacuum or metal reference state is certainly useful.…”

Section: Defect Formation Energiesmentioning

confidence: 99%

Comparative computational study of the energetics of Li, Na, and Mg storage in amorphous and crystalline silicon

Legrain

Computational Materials Science

Manzhos

2014

Self Cite

To assess the potential of amorphous Si (a-Si) as an anode for Li, Na, and Mg-ion batteries, the energetics of Li, Na, and Mg atoms in a-Si are computed from first-principles and compared to those in crystalline Si (c-Si). It is shown that Si preamorphization increases the average anode voltage and reduces the volume expansion of the anode during the insertion of the metal atoms.Analysis of computed formation energies of Li, Na, and Mg defects in a-Si and c-Si suggests that the energetics of the single atoms into a-Si are thermodynamically more favorable. For instance, defect formation energies of Li, Na, and Mg defects in a-Si are respectively 0.71, 1.72, and 1.82 eV lower compared to those in c-Si. Moreover, the defect formation energies of Li, Na, and Mg defects (vs. vacuum reference states) in a-Si are comparable with the metal cohesive energies and consequently the insertion of the metal atoms might be possible with appropriate control of charging process. This is in contrast to c-Si, where the storage of Na and Mg atoms is limited due to high energy cost of Na and Mg insertion into c-Si.