The influence of stress field on Li electrodeposition in Li-metal battery
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Research Letter
The influence of stress field on Li electrodeposition in Li-metal battery Vitaliy Yurkiv, Tara Foroozan, Ajaykrishna Ramasubramanian, Reza Shahbazian-Yassar, and Farzad Mashayek, Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA Address all correspondence to Vitaliy Yurkiv and Farzad Mashayek at [email protected] and [email protected] (Received 25 May 2018; accepted 18 July 2018)
Abstract Lithium (Li) dendrite formation in Li-metal batteries (LMBs) remains a key obstacle preventing LMBs from their widespread application. This study focuses on the role of the stress field in the Li electrodeposits formation and growth. Coupled electrochemical and mechanical phasefield model (PFM) is used to investigate electrodeposited Li evolution under different conditions. The PFM results, using both the anisotropic elastic properties of Li and the random delivery of Li-ions through the solid electrolyte interface, show a significant local stress development indicating a direct correlation between the stress field and the origin of the undesired Li filaments initiation.
Introduction Lithium (Li)-metal secondary batteries (LMBs) are one of the most promising energy storage technologies to be used in future electric vehicles and grid storage, due to their ultrahigh theoretical capacity (3860 mAh/g) and low redox potential (−3.04 V versus standard hydrogen potential, H2/H+).[1] However, the successful usage of LMBs is limited due to the undesired formation of Li electrodeposits in the form of filaments or dendrites, which cause mechanical deformation of the electrode and in the worst case internal electric short circuit.[2–5] There is significant foregoing research regarding the harmful influence of randomly shaped Li electrodeposits on LMB’s performance, based upon which many experimental methods to suppress undesired dendritic formation have been developed.[6–12] A number of theoretical studies[13–17] have investigated the morphological evolution of Li electrodeposits; however, only one work[16] has included the effect of the stress field in the calculations of Li dendrites/filaments formation. Most of these studies show that the stress field originated from the electrodeposited Li plays a crucial role in the growth rate and morphology of Li electrodeposits. Although these studies discuss the effect of stress on the Li electrodeposition, the clear evidence to what extent the elastic energy contribution influences solid Li growth have not been provided. Only recently, Wang et al.[12] have shown that stiffness of the substrate on which Li electrodeposits has a direct influence on the shape and rate of solid Li deposition. In particular, they show that Li dendrites/filaments formation in the presence of carbonate-based electrolytes can be suppressed by means of soft substrates, where the generated residual stress can be released. It should be noted that the conclusions made by Wang et al. would not be possible without a significant contribution from the prior work by Ku
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