Size Dependence of Transport Non-Uniformities on Localized Plating in Lithium-Ion Batteries

Abstract

Plating in lithium-ion batteries not only reduces their lifetime, but also raises safety concerns. Preventing metallic lithium from forming is difficult, as the heterogeneity of materials typically used in batteries can create transport non-uniformities, which can lead to unanticipated local plating. Therefore, being able to predict the occurrence of plating due to a non-uniformity of a certain shape and size becomes essential. In this study, we probe the importance of the size scale and geometry on localized plating through numerical simulations and experiments. Using modified separators to create transport non-uniformities, we show that certain geometric features lead to more vulnerability to plating, and localization strongly depends on size. A single large feature in a separator induces more plating than a collection of smaller features with same total area. Our findings help elucidate the fundamentals behind heterogeneous plating, which can provide practical insights into battery safety and product control.

The influence of surface inhomogeneity on the overcharge and lithium plating of graphite electrodes

“…We find that if the amount of deposited Li needed to obtain the activity of bulk Li is significantly less than the capacity of the graphitic host, i.e. if L c , [1][2][3][4][5][6], have assumed that the plated Li does not react directly with graphite vacancies at the interface (see reaction (15)), even though the plated Li resides directly on the graphitic surface ( figure 1(c)), i.e. atoms of deposited Li are within angstroms of vacant sites within the graphite.…”

“…As lithium ion batteries become more prevalent, particularly in automotive electric-traction applications, clarification of phenomena that limit the charge rate of such batteries, including lithium (Li) plating over the graphite negative electrode [1][2][3][4][5][6], is becoming ever more important. The recent paper by researchers at Argonne National Laboratory (ANL) [7] provides a helpful summary of lithium-plating investigations.…”

“…In addition, the use of ceramic materials over the graphite electrode, as employed in ceramicenhanced separators [19], leads to blockage of reactions over portions of the electrode. Insulating contaminants can also occlude portions of the graphite surface [3,5].…”

A Nacre‐Inspired Separator Coating for Impact‐Tolerant Lithium Batteries

“…Under the stress of external shock, the microporous polyolefin separator can easily deform, accompanied with the change of inside porous network, including the pore closure, leading to the inhomogeneous Li + ion flux in the battery . The nonuniform Li + ion flux can then create high local current density to trigger lithium dendrite growth on the electrode, resulting in short circuit and even explosion of lithium batteries …”

“…Although the commercialized separator is protected by the ceramic nanoparticle coating, the stress applied on the surface of polyolefin separator still exhibits highly localized distribution characteristic because the randomly packed ceramic nanoparticle cannot disperse the stress, implying that the catastrophically perforated damage would also occur in the commercialized CNCS ( Figure a). The formed abnormal pore network structure under the compressive stress would cause nonuniform Li + ion flux (red arrow in Figure a) and probably trigger the lithium dendrite growth, inducing short circuit and even explosion of lithium batteries …”