Lithium-Ion Model Behavior in an Ethylene Carbonate Electrolyte Using Molecular Dynamics

Kumar, Narendra; Seminario, Jorge M.

doi:10.1021/acs.jpcc.6b03709

Cited by 90 publications

(88 citation statements)

References 58 publications

(107 reference statements)

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“…56 in which, this combination of force elds was used successfully in a Li-ion full nanobattery with Si electrodes, 56 and also with a very similar combined force-eld by Kumar et al 59 in the modelling of Li-diffusion through the electrolyte, obtaining good agreement with experimental results.…”

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confidence: 80%

Dendrite formation in silicon anodes of lithium-ion batteries

Selis

Seminario

2018

RSC Adv.

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Rechargeable lithium-ion batteries require a vigorous improvement if we want to use them massively for high energy applications. Silicon and metal lithium anodes are excellent alternatives because of their large theoretical capacity when compared to graphite used in practically all rechargeable Li-ion batteries.However, several problems need to be addressed satisfactorily before a major fabrication effort can be launched; for instance, the growth of lithium dendrites is one of the most important to take care due to safety issues. In this work we attempt to predict the mechanism of dendrite growth by simulating possible behaviors of charge distributions in the anode of an already cracked solid electrolyte interphase of a nanobattery, which is under the application of an external field representing the charging of the battery; thus, elucidating the conditions for dendrite growth. The extremely slow drift velocity of the Li-ions of $1 mm per hour in a typical commercial Li-ion battery, makes the growth of a dendrite take a few hours; however, once a Li-ion arrives at an active site of the anode, it takes an extremely short time of $1 ps to react. This large difference in time-scales allows us to perform the molecular dynamics simulation of the ions at much larger drift velocities, so we can have valuable results in reasonable computational times. The conditions before the growth are assumed and conditions that do not lead to the growth are ignored. We performed molecular dynamics simulations of a pre-lithiated silicon anode with a Li : Si ratio of 21 : 5, corresponding to a fully charged battery. We simulate the dendrite growth by testing a few charge distributions in a nanosized square representing a crack of the solid electrolyte interphase, which is where the electrolyte solution comes into direct contact with the LiSi alloy anode.Depending on the selected charge distributions for such an anode surface, the dendrites grow during the simulation when an external field is applied. We found that dendrites grow when strong deviations of charge distributions take place on the surface of the crack. Results from this work are important in finding ways to constrain lithium dendrite growth using tailored coatings or pre-coatings covering the LiSi alloy anode.

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confidence: 80%

Dendrite formation in silicon anodes of lithium-ion batteries

Selis

Seminario

2018

RSC Adv.

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“…For example, quantum calculations track electrons and can characterize decomposition of electrolytes at anode surfaces [ 8 , 9 , 22 , 27 , 28 ]. These methods include ab initio molecular dynamics (AIMD), which have the drawback of computational expense and the concomitant limitation to small systems and time scales [ 29 – 31 ]. On the other hand, if chemical changes such as chemical bond rearrangement are essential to the study, AIMD provides natural perspectives on those phenomena.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Simple Models for Molecular Simulation of Ethylene Carbonate and Propylene Carbonate as Solvents for Electrolyte Solutions

et al. 2018

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Progress in understanding liquid ethylene carbonate (EC) and propylene carbonate (PC) on the basis of molecular simulation, emphasizing simple models of interatomic forces, is reviewed. Results on the bulk liquids are examined from the perspective of anticipated applications to materials for electrical energy storage devices. Preliminary results on electrochemical double-layer capacitors based on carbon nanotube forests and on model solid-electrolyte interphase (SEI) layers of lithium ion batteries are considered as examples. The basic results discussed suggest that an empirically parameterized, non-polarizable force field can reproduce experimental structural, thermodynamic, and dielectric properties of EC and PC liquids with acceptable accuracy. More sophisticated force fields might include molecular polarizability and Buckingham-model description of inter-atomic overlap repulsions as extensions to Lennard-Jones models of van der Waals interactions. Simple approaches should be similarly successful also for applications to organic molecular ions in EC/PC solutions, but the important case of Li deserves special attention because of the particularly strong interactions of that small ion with neighboring solvent molecules. To treat the Li ions in liquid EC/PC solutions, we identify interaction models defined by empirically scaled partial charges for ion-solvent interactions. The empirical adjustments use more basic inputs, electronic structure calculations and ab initio molecular dynamics simulations, and also experimental results on Li thermodynamics and transport in EC/PC solutions. Application of such models to the mechanism of Li transport in glassy SEI models emphasizes the advantage of long time-scale molecular dynamics studies of these non-equilibrium materials.

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“…32) and that the distance between Li+ and oxygen of EC or DMC is z0.2 nm. 33 The lithiation-delithiation of LTO is a complex process, which was believed to be kinetically dominated by electronic conductivity. 27 However, it was recently reported that the electronic conductivity is only one of the crucial factors, especially in the case of nanostructured LTO, where Li ion transport ability becomes a predominant or competitive factor along with electronic conductivity.…”

Section: Resultsmentioning

confidence: 99%