Insights into the effects of multi-layered graphene as buffer/interlayer for a-Si during lithiation/delithiation

Jangid, Manoj K.; Sonia, Farjana J.; Kali, Ravi; Ananthoju, Balakrishna; Mukhopadhyay, Amartya

doi:10.1016/j.carbon.2016.10.032

Cited by 59 publications

(103 citation statements)

References 70 publications

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“…Another important observation is that, despite being partly cracked, the films appeared to remain intact and not delaminated even after 100 cycles, unlike observations usually made with such a-Si films upon repeated lithiation/delithiation cycles. 20,21 Overall, the present results/observations indicate in very strong terms that, even though reversible electrochemical Na-alloying is possible in a-Si, dimensional scale of the active material (when used as stand-alone) is a very important criterion with respect to the performance; with preferred dimensions being below ∼50 nm. 23 reported Na diffusivity in crystalline Si (c-Si) to be of the order of ∼ 6 × 10 −16 m 2 s −1 , even at considerably higher temperature of 800…”

Section: Resultsmentioning

confidence: 51%

“…These observations tend to support the hypothesis that the observed 'activation' for the 250 nm film was, at least partly, related to the overall Na transport limitation. In this context, it is also believed that upon electrochemical Na-insertion/removal, the active a-Si film gets cracked (thus partly reducing the Na transport distances) and also 'expanded' irreversibly (similar to that reported in the case of Li-insertion/removal 20 ), thus improving the overall Na transport kinetics with progress in cycling. This, in fact, becomes particularly apparent (and dominant in the initial cycles) for the thickest a-Si film used here (i.e., the ∼250 nm thick film), sodiation/desodiation of which is severely Na transport limited at the beginning, and which also shows greater severity of cracking (compare Figs.…”

Section: Resultsmentioning

confidence: 74%

“…Even though cracks could be observed during SEM observations of all the a-Si films discharged/charged for 100 cycles (after removal of surface films following procedure described earlier 20 ), severity of 'damage' was lesser for the thinner films (see Figs. 3d-3f).…”

Section: Resultsmentioning

confidence: 97%

See 2 more Smart Citations

Feasibility of Reversible Electrochemical Na-Storage and Cyclic Stability of Amorphous Silicon and Silicon-Graphene Film Electrodes

Jangid

Vemulapally

Sonia

et al. 2017

J. Electrochem. Soc.

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The feasibility of reversible electrochemical Na-alloying in amorphous silicon (a-Si), along with influences of transport limitations of Na, dimensional aspects of a-Si and usage of few layers graphene (FLG) as interlayer (between a-Si and current collector) on Na-capacities and cyclic stabilities, have been demonstrated here with the use of continuous film electrodes (sans binder/additive). Systematic variations of a-Si film thicknesses have indicated that electrochemical Na-alloying, even though feasible, is 'transport limited', especially for a-Si dimensions beyond ∼100 nm. Nevertheless, decent performances, such as initial reversible Na-capacities of ∼340 mAh g −1 , with ∼120 mAh g −1 retained after 100 cycles, could be achieved upon reduction of film thickness to 50 nm. Analytical computation studies indicate that overall diffusivity of Na in such a-Si electrodes may be of the order of ∼10 −19 m 2 s −1 . In the presence of FLG interlayer (∼7 well-ordered continuous graphene layers), 'transport limitation' related issues got suppressed even for 250 nm thick a-Si film; viz., leading to considerably enhanced Na-capacities and improved cyclic stabilities. Accordingly, reversible Na-capacities recorded with the 250 and 50 nm a-Si films at the end of 100 cycles were ∼120 and ∼240 mAh g −1 ; which are possibly the best reported to-date for Si-based electrode materials. Due to limited lithium reserves in the world as compared to the more widespread and abundant reserves of sodium, there has been recent surge of interests toward the development of Na-ion batteries (SIBs), possibly in lieu of the Li-ion technology.1,2 However, one of the major issues associated with the Na-ion system is that graphitic carbon, the commonly used anode material for Li-ion batteries (LIBs), possesses reversible Na-capacity of just ∼35 mAh g −1 .1, [3][4][5][6][7][8][9] This is an order of magnitude lower compared to the corresponding Li-capacity; 3,10-12 and is caused by the larger size of the Na-ion. Accordingly, metallic anode materials, such as Ge, Sb and Sn, have been investigated for SIBs, but without much success in terms of cyclic stabilities due to dimensional changes (and detrimental stress developments) upon Na-alloying/dealloying. [3][4][5][6] It is a bit surprising that silicon, which possesses possibly the highest theoretical capacity for Li and extensively investigated for LIBs, was hitherto believed to be 'inactive' toward sodiation via electrochemical routes.6-10,13 Kulish et al., 8 via first principles, showed that sodiation of bulk Si is unfavorable, with Na binding energies being 0.6 eV, along with larger diffusion barrier of 1.06 eV. By contrast, the available Na-Si phase diagram 14 indicates that Na-alloying in Si is possible (up to Na 1 Si phase); with more recent calculations predicting that one Si atom can host at most 0.76 Na (i.e., up to Na 0.76 Si; corresponding to specific capacity of ∼725 mAh g −1 ). 11 Such predicted Na-capacity, even though significantly lesser compared to the Li-capacity, would still be co...

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Section: Resultsmentioning

confidence: 51%

Section: Resultsmentioning

confidence: 74%

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Feasibility of Reversible Electrochemical Na-Storage and Cyclic Stability of Amorphous Silicon and Silicon-Graphene Film Electrodes

Jangid

Vemulapally

Sonia

et al. 2017

J. Electrochem. Soc.

Self Cite

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“…However, the mechanical constraint that stems from such a thin surface layer can dramatically change the lithiation morphology of the SiNW along the radial direction, which indicates that the lithiation-generated Li x Si phase possesses ultrahigh malleability and deformability. With the invasion of Li, the strength of the Si/C interface is continuously reduced, − and the SiNW finds it easier to expand along the axial, rather than radial, direction when the lithiation proceeds to certain extent, leading to enhanced stress toward the end of the SiNW far away from the Li metal counter electrode. This can explain well why the C coating breaks toward the end of the SiNW far away from the Li metal counter electrode, and not at the other locations along the SiNW where the lithiation level is much higher.…”

Section: Results and Discussionmentioning

confidence: 99%

Ultrahigh Malleability of the Lithiation-Induced Li_xSi Phase

Shi

Zhu

Xia

et al. 2018

ACS Appl. Energy Mater.

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Through in situ transmission electron microscopy (TEM) observation, the lithiation behaviors of carboncoated silicon (Si) nanostructures are investigated. Our experimental results reveal that the carbon (C) coating can not only mediate the lithiation kinetics and volume expansion, leading to the retardation or even complete suppression of the lithiation process, but also determine the morphological evolution and final shape of the lithiation products. The lithiation behaviors of C-coated Si nanostructures are further corroborated by chemo-mechanical simulations. Our study consistently demonstrates that the effect of C coating layer on the lithiation behaviors of Si nanostructures is closely related to the ultrahigh malleability and deformability of the lithiation-induced Li x Si phase. The finding of this study sheds light on the rational design of high-performance Si−C composite electrode materials.

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“…[34,61] This geometrical change strains the SEI until it eventually fractures, which leads to formation of new SEI upon direct contact between electrolyte and electrode. [31,[62][63][64] Several groups developed mechanistic models to describe the mechanical response of the SEI on battery cycling. [14,[64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79] However, these models focus on SEI mechanics and incorporate at most simple SEI growth models.…”

Section: Introductionmentioning

confidence: 99%

Chemo‐Mechanical Model of SEI Growth on Silicon Electrode Particles**

Kolzenberg

Latz

Horstmann

2021

Batteries & Supercaps

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Silicon anodes promise high energy densities of next-generation lithium-ion batteries, but suffer from shorter cycle life. The accelerated capacity fade stems from the repeated fracture and healing of the solid-electrolyte interphase (SEI) on the silicon surface. This interplay of chemical and mechanical effects in SEI on silicon electrodes causes a complex aging behavior. However, so far, no model mechanistically captures the interrelation between mechanical SEI deterioration and accelerated SEI growth. In this article, we present a thermodynamically consistent continuum model of an electrode particle surrounded by an SEI layer. The silicon particle model consistently couples chemical reactions, physical transport, and elastic deformation. The SEI model comprises elastic and plastic deformation, fracture, and growth. Capacity fade measurements on graphite anodes and in-situ mechanical SEI measurements on lithium thin films provide parametrization for our model. For the first time, we model the influence of cycling rate on the long-term mechanical SEI deterioration and regrowth. Our model predicts the experimentally observed transition in time dependence from square-root-of-time growth during battery storage to linear-in-time growth during continued cycling. Thereby our model unravels the mechanistic dependence of battery aging on operating conditions and supports the efforts to prolong the battery life of next-generation lithium-ion batteries.

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Insights into the effects of multi-layered graphene as buffer/interlayer for a-Si during lithiation/delithiation

Cited by 59 publications

References 70 publications

Feasibility of Reversible Electrochemical Na-Storage and Cyclic Stability of Amorphous Silicon and Silicon-Graphene Film Electrodes

Feasibility of Reversible Electrochemical Na-Storage and Cyclic Stability of Amorphous Silicon and Silicon-Graphene Film Electrodes

Ultrahigh Malleability of the Lithiation-Induced Li_xSi Phase

Chemo‐Mechanical Model of SEI Growth on Silicon Electrode Particles**

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Insights into the effects of multi-layered graphene as buffer/interlayer for a-Si during lithiation/delithiation

Cited by 59 publications

References 70 publications

Feasibility of Reversible Electrochemical Na-Storage and Cyclic Stability of Amorphous Silicon and Silicon-Graphene Film Electrodes

Feasibility of Reversible Electrochemical Na-Storage and Cyclic Stability of Amorphous Silicon and Silicon-Graphene Film Electrodes

Ultrahigh Malleability of the Lithiation-Induced LixSi Phase

Chemo‐Mechanical Model of SEI Growth on Silicon Electrode Particles**

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Product

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Ultrahigh Malleability of the Lithiation-Induced Li_xSi Phase