Low-Temperature Lithium Plating/Corrosion Hazard in Lithium-Ion Batteries: Electrode Rippling, Variable States of Charge, and Thermal and Nonthermal Runaway

Abstract

Spatially dependent low-temperature to roomtemperature degradation mechanisms for Li(Ni 0.5 Mn 0.3 Co 0.2 )O 2 / Li x C 6 (NMC532/graphite) large format 50Ah Li-ion batteries were investigated. First, highly stressed regions of the cathode/ anode are found to be exacerbated by extreme conditions (i.e., lowtemperature cycling). The severe electrochemical polarization of large 50Ah electrodes at low temperature leads to substantial Li 0 deposition and severe gassing at the regions of high stress (i.e., high curvature, edges, and electrode ripples). A series of analytical techniques (e.g., SEM, XPS, GC-MS, and Raman spectroscopy) found that Li 0 plating (charge) or corrosion (storage) leads to severe gassing and decomposition products (including carbides). The expansion/contraction and extreme polarization during lowtemperature cycling, was found to cause a ripple-type Li 0 deposition on the electrode. Multilocation liquid nitrogen (N 2 ) Raman spectroscopy of electrodes indicates significant quantities of Li 0 deposition reside at ripple peaks (high-stress region) and are found negligible at ripple troughs. Postmortem analysis discovered two failure scenarios that originate from low-temperature cycling, either nonthermal runaway venting or an internally shorted thermal runaway. It was found in the first case (storage) that LiC 6 −Li 0 undergoes severe corrosion and gassing during storage conditions (i.e., no movement, current, and temperature) and proceeds to trigger thermal runaway and ejection of materials (∼2 weeks). The second case (RT cycling after low temperature) resulted in nonthermal runaway overpressurized venting of the cell and release of detectable quantities of flammable/toxic gases (e.g., CO 2 , CO, CH 4 , and C 2 H 2 ). The second event was found to be caused by competing reactions (i.e., Li 0 stripping, Li 0 corrosion, and severe gassing). This study finds that low-temperature Li 0 plating and LiC 6 −Li 0 corrosion results in severe gassing, which exacerbates highly stressed regions (i.e., electrode buckling) and greatly compromises safety of the application via nonthermal runaway venting when cycled (e.g., stripping of Li 0 and gassing) and catastrophic thermal runaway when resting under storage (e.g., larger quantities of Li x C 6 −Li 0 corrosion).

Alloying Germanium Nanowire Anodes Dramatically Outperform Graphite Anodes in Full-Cell Chemistries over a Wide Temperature Range

“… 62 Carbide formation at low temperatures can be attributed to lithium decomposition at the anode’s edge. 63 The introduction of PC was found to largely suppress carbide formation and reduce the relative concentration of the carbonate-containing species, indicative of less lithium being consumed at the anode surface. Additionally, PC was found to promote Li ether incorporation in the SEI layer.…”

Research Progress of Lithium Plating on Graphite Anode in Lithium‐Ion Batteries

“…To summarize the above mentioned detecting approaches of Li plating, voltage profiles during charge/discharge [ 55‐56 ] and relaxation [ 28,43‐44,57 ] processes are the main electrochemical characteristics of Li plating, and some physical characterization techniques have been applied to detect Li plating, such as scanning/transmission electron microscopy (SEM/TEM), [ 16,58‐61 ] nuclear magnetic resonance spectroscopy (NMR) [ 28,62 ] and neutron diffraction. [ 44‐45 ] The SEM images of Li plating on graphite anode are represented in Refs [61] and [63]. The Li deposits present whisker and cauliflower‐like morphologies, respectively, as is shown in Figure 5d and Figure 5e.…”

“…(a, b, c) Schematic illustration explaining root growth mechanism of Li deposits [ 65 ] (Copyright 2016, Elsevier) and (d, e) SEM images of Li deposits on graphite anode reported in Ref [61] (Copyright 2016, Elsevier) and [63] (Copyright 2020, American Chemical Society).…”

Lithium Plating Detection Methods in Lithium-Ion Batteries

“…[150] ) and illustrate the increase in plating rate at lower temperatures, consistent with experimental studies. [45,63,93,[154][155][156][157][158] Choe has applied this reduced order model to investigate degradation with the intent of mitigating aging and Li plating due to fast charging. [140,[150][151][152][159][160][161][162][163] This type of approach could be utilized in a battery management system or charge controller to avoid Li plating completely, or to allow for a quantifiable amount of Li plating that could be electrochemically removed later.…”