In Situ Observation of Dendrite Growth of Electrodeposited Li Metal

Abstract

The dendrite growth behavior of Li metal galvanostatically electrodeposited on Ni substrate in a LiClO 4 -propylene carbonate electrolyte solution was in situ observed by a laser scanning confocal microscope with a metallographic microscope. A Li dendrite precursor is stochastically evolved on Ni substrate probably through a solid electrolyte interphase layer produced by the surface chemical reaction between a reduced Li metal and an organic electrolyte. The measured length of randomly growing Li dendrite arms was statistically analyzed. The initiation period of the dendrite precursor becomes shorter with increasing current density and decreasing LiClO 4 concentration. Once it has been initiated, the ionic mass transfer rate starts to govern the growth process of the dendrite arm length, exceeding over the surface chemistry controlling step. The dendrite arm length averaged over the substrate surface grows linearly proportional to the square root of time. The lower the concentration of LiClO 4 , the steeper the inclination of the line at 5 mA cm −2 , whereas the concentration dependence of inclination is not evident at 0.5 mA cm −2 .

Morphological Variation of Electrodeposited Li in Ionic Liquid

“…In previous report, this model shows good agreement with the measured electrode surface concentration even in the Li electrode system [13][14][15] .…”

“…The electrode thickness was 200 μm enough to rotate for 50 μm dendrite observed in Fig.4. Such a rotating movement during the Li electrodeposition has been also observed in the organic electrolyte system reported in the previous research 16,17 . , 41 (41) 3-10 (2012) phenomenon.…”

“…Such information must help the restriction of Li dendrite growth and realization for the Li metal negative electrode. In our previous reports, the time transient of the surface concentration and the concentration profile in the vicinity of the electrode during the electrodeposition of Li metal in organic electrolytes and ionic liquids was in-situ measured by a holographic interferometry technique [12][13][14][15] . At the initial stage of the electrodeposition, the side reactions which are mainly SEI forming reaction induces the incubation period.…”

Study of the Mechanisms of Internal Short Circuit in a Li/Li Cell by Synchrotron X-ray Phase Contrast Tomography

“…67 The above-observed results agree well with previous simulations. 15,[68][69] Additionally, the direct internal view of the electrochemically short circuited Li/Li-2 cell suggests that the shutdown mechanism proposed by the sandwich structure can hardly provide any protection from a real ISC, i.e. the considerable force accompanied by the growing LmSs and the ISC-induced high Joule heating easily destroy the trilayer separator that is made by laminating PP and PE layers together by adhesion or welding.…”

Quantifying the dependence of dead lithium losses on the cycling period in lithium metal batteries

“…20,[43][44][45] The preceding analysis suggests that thinner i.e., higher curvature necks are produced in the later stages of extended charging cycles, thereby increasing the probability of DLC detachment during discharge. 5,25,30,46,47 The fact that DLCs appear preferentially at longer charging times implies that the root segments (necks) of the dendrite structures produced in later stages are thinner and/or longer. 33 Thinner longer 'necks' have a larger positive (convex) curvature radius, r convex , about their cross sections, and a smaller negative (concave) curvature radius, r concave , about their columns.…”