Lithium Dendrite Growth Control Using Local Temperature Variation
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Lithium Dendrite Growth Control Using Local Temperature Variation Asghar Aryanfar1*, AgustÃn J Colussi2 and Michael R. Hoffmann2 1
Mechanical Engineering, 2Environmental Science and Engineering, California Institute of Technology, Pasadena, CA 91125, U.S.A.
ABSTRACT We have quantified lithium dendrite growth in an optically accessible symmetric Limetal cell, charged under imposed temperatures on the electrode surface. We have found that the dendrite length measure is reduced up to 43% upon increasing anodic temperature of about 500C. We have deduced that imposing higher temperature on the electrode surface will augment the reduction rate relative to dendritic peaks and therefore lithium holes can draw near with the sharp deposited tips. We have addressed this mechanism via fundamentals of electrochemical transport.
INTRODUCTION In recent years, wireless revolution and need for harnessing intermittent renewable energy sources, has created an exponential demand for long-lasting and high capacity energy storage devices with high-power delivery, such as batteries [1, 2]. Lithium metal, particularly, as a candidate for anode material with an ideal energy density of 3862 mAh/g, could drastically address this demand. However, it has high propensity to grow dendrites during subsequent charging periods. The dendrites might eventually lead to short-circuit and initiate a current within the cell which causes overheating and ignition of the organic electrolyte solvents commonly used in such devices [3, 4]. The current reports on lithium dendrite have investigated the effect of charging method [5, 6] current density [7-9], electrode morphology[10-12], solvent and electrolyte chemical composition [13-15], and evolution time [16] on dendrite growth. Other methods include the use of powder electrodes [17] and adhesive polymers [18] and describing concentration variations [19, 20]. Existing useful dendrite characterizations naturally involve simplifying assumptions such as one dimensional cell geometry that may have fallen short of capturing the comprehensive essentials of dendrite growth in realistic systems [8, 21]. On the temperature effect, researchers have found that cycling at higher temperatures (from 500C up to 40oC) can, on average, cause more and more frequent short-circuiting events up to a factor of 2 [22]. Other results show that the increasing cell temperature enhances the ionic mobilities in favor of dendritic inception and growth [23]. [19, 24] reported that the higher temperatures extends ion depletion layer length which is in agreement reaction rates (probability of ionic reduction) direction correlation with temperature [25]. In contrast,[26] found that *
Corresponding Author: [email protected]
imposing higher temperatures reduces dendrite growth rate relatively to the electrode surface, and could results in more uniform deposition. Although all those approaches are helpful, it is apparent that further progress in tackling this crucial issue should accrue from a full understanding of the dynamics of dendr
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