Effects of 30° partial dislocation and stacking fault on Na and Mg storage and diffusion in Si anode

Wang, Chaoying; Li, Hecheng; Li, Chenliang; Wu, Guoxun; Sang, Tianyi; Yang, Lijun; Wang, Zhenqing

doi:10.1016/j.commatsci.2016.03.001

Cited by 5 publications

(2 citation statements)

References 50 publications

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“…15) We clarified experimentally that the SF formation energy is reduced in Si contaminated with Na atoms, as theoretically predicted. 12,13) Once contaminated SFs are formed, Na atoms can diffuse preferentially along the SFs because the activation energy for Na diffusion in the SFs is lower than that in bulk Si. 12) Under a constant PID stress, the expansion rate of SFs determined by the Na diffusion increases with the increasing distance from the SiN x =Si interface, owing to the reduction in the SF formation energy depending on the Fermi level (Fig.…”

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confidence: 99%

Interaction of sodium atoms with stacking faults in silicon with different Fermi levels

Ohno

Morito

Kutsukake

et al. 2018

Appl. Phys. Express

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Variation in the formation energy of stacking faults (SFs) with the contamination of Na atoms was examined in Si crystals with different Fermi levels. Na atoms agglomerated at SFs under an electronic interaction, reducing the SF formation energy. The energy decreased with the decrease of the Fermi level: it was reduced by more than 10 mJ/m 2 in p-type Si, whereas it was barely reduced in n-type Si. Owing to the energy reduction, Na atoms agglomerating at SFs in p-type Si are stable compared with those in n-type Si, and this hypothesis was supported by ab initio calculations.

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confidence: 99%

Interaction of sodium atoms with stacking faults in silicon with different Fermi levels

Ohno

Morito

Kutsukake

et al. 2018

Appl. Phys. Express

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“…However, earlier computational − and experimental studies , with crystalline Si disappointed the community by predicting/indicating that Si might be “inactive” toward hosting Na under the relevant electrochemical conditions. In fact, Kulish et al predicted a fairly large diffusion barrier (1.06 eV) and a positive binding energy (of 0.6 eV) for Na alloying with Si using first-principles calculations, although this conclusion was busted by the more recent studies, including ours, which indicated that it is primarily the limitation of Na transport in the coarser-sized Si particles/films ,,− and crystalline/defect-free nature of Si ,− ,− ,− that cause significant hindrance in Na uptake. In fact, our previously reported studies established that amorphous Si, unlike crystalline Si, does exhibit reversible Na alloying under the electrochemical conditions pertaining to being the anode of Na-ion cells. , Nevertheless, sodiation/desodiation was found to be kinetically more hindered, as compared to Li insertion/removal kinetics, since finer Si dimensions (preferably <∼50 nm) are needed for obtaining practically any useful performance as an anode material.…”

Section: Introductionmentioning

confidence: 72%

Revealing Na-segregation at the Si/Graphene Interface and Its Implications toward the Na-storage Behavior of Si-Based Electrodes

Raghuvanshi

Jangid

Bhattacharya

et al. 2022

ACS Appl. Mater. Interfaces

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The feasibility of reversible alloying of Na with Si has led to Si being considered as a potential anode material for the upcoming Na-ion battery system. However, Si exhibits useful Na-storage capacity and associated electrochemical cyclic stability only in the presence of graphene-based interlayers/additives. Despite this, no knowledge exists concerning the characteristics/phenomena at the Si/graphene interface and the possible influence of the same toward Na-storage behavior/performance. Against this backdrop, a combination of first-principles-based calculations and experimental investigations has revealed here the occurrence of preferential Na-segregation at the Si/graphene interface. Bader charge analysis indicates that when positioned right at the interface, Na undergoes the greatest extent of charge transfer (to become positively charged), with electrons being transferred primarily to the more electronegative C (as compared to Si). More importantly, the binding energy of Na assumes the most negative value at the interface. Furthermore, the overall energy of the Na-Si-graphene system gets minimized to the greatest extent when the Na atom gets located at the Si/graphene interface. The abovementioned predictions have been verified by mapping the Na-concentrations from the surfaces of galvanostatically sodiated amorphous Si films down to bare Cu or graphene-coated Cu substrates (i.e., across Si film thickness) via depth profiling ToF-SIMS. Such measurements indicate that the overall Na-concentration in the sodiated Si film is considerably greater in the presence of a graphene-based interlayer between Si and Cu, thus agreeing with the as-observed enhanced Na-storage capacity. More importantly, the observation of a definite “hump” in the Na-concentration profile very close to the Si/graphene interface, in contrast to almost no Na-concentration close to the Si/Cu interface in the absence of a graphene-based interlayer, is direct evidence for preferential Na-segregation at the Si/graphene interface (unlike at the Si/Cu interface).

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The influence of crack on the Si anode performance in Na- and Mg-ion batteries: An atomic multiscale study

Wang

Zhang

Xue

et al. 2022

Computational Materials Science

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Effects of 30° partial dislocation and stacking fault on Na and Mg storage and diffusion in Si anode

Cited by 5 publications

References 50 publications

Interaction of sodium atoms with stacking faults in silicon with different Fermi levels

Interaction of sodium atoms with stacking faults in silicon with different Fermi levels

Revealing Na-segregation at the Si/Graphene Interface and Its Implications toward the Na-storage Behavior of Si-Based Electrodes

The influence of crack on the Si anode performance in Na- and Mg-ion batteries: An atomic multiscale study

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