SPEs exhibit low volatility and thus increase the safety of Li-based batteries compared to current state-of-the-art Li-ion batteries that use flammable small-molecule electrolytes. Solid polymer electrolyte (SPE) membranes are a critical component of high specific energy rechargeable Li-metal polymer (LMP) batteries. 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. We found that dendrites grow when strong deviations of charge distributions take place on the surface of the crack. Depending on the selected charge distributions for such an anode surface, the dendrites grow during the simulation when an external field is applied.
#EFFECT OF DENDRITE STRUCTURE CRACK#
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. 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. The conditions before the growth are assumed and conditions that do not lead to the growth are ignored. 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 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.
#EFFECT OF DENDRITE STRUCTURE CRACKED#
In this work we attempt to predict the mechanism of dendrite growth by simulating possible behaviors of charge distributions in the more » 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. 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. 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. Rechargeable lithium-ion batteries require a vigorous improvement if we want to use them massively for high energy applications. The simulations suggest that a control of electrolyte parameters that impact lithium diffusion might be an attractive route to controlling dendrite = , We observe a structural change from broccoli to cauliflower shape as the diffusion constant is increased. Additionally, the growth is most pronounced when the applied voltage and diffusion constant are both low. We find that the diffusion constant is the most significant factor, and the inhomogeneity of the electric field does not play a significant role.
Using stochastic dynamics simulations, we investigate the effect of applied voltage and diffusion constant on the growth of dendrites. In this work, we study the growth of dendrites in a simple model system where the solvent is a continuum and the lithium ions are hard spheres that can deposit by sticking to existing spheres or the electrode surface. Lithium dendrites can lead to a short circuit and battery failure, and developing strategies for their suppression is of considerable importance.
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