A New Method for Quantitative Marking of Deposited Lithium by Chemical Treatment on Graphite Anodes in Lithium‐Ion Cells

A novel approach for the marking of deposited lithium on graphite anodes from large automotive lithium‐ion cells (≥6 Ah) is presented. Graphite anode samples were extracted from two different formats (cylindrical and pouch cells) of pristine and differently aged lithium‐ion cells. The samples present a variety of anodes with various states of lithium deposition (also known as plating). A chemical modification was performed to metallic lithium deposited on the anode surface due to previous plating with isopropanol (IPA). After this procedure an oxygenated species was detected by scanning electron microscopy (SEM), which later was confirmed as Li₂CO₃ by Fourier transform infrared spectroscopy (FTIR) and X‐ray powder diffraction (XRPD). A valuation of the covered area by Li₂CO₃ was carried out with an image analysis using energy‐dispersive X‐ray spectroscopy (EDX) and quantitative Rietveld refinement.     

On Orthogonal Double Covers of Graphs

An orthogonal double cover (ODC) is a collection of n spanning subgraphs(pages) of the complete graph K _n such that they cover every edge of the completegraph twice and the intersection of any two of them contains exactly one edge. If all the pages are isomorphic tosome graph G, we speak of an ODC by G. ODCs have been studied for almost 25 years, and existenceresults have been derived for many graph classes. We present an overview of the current state of research alongwith some new results and generalizations. As will be obvious, progress made in the last 10 years is in many waysrelated to the work of Ron Mullin. So it is natural and with pleasure that we dedicate this article to Ron, on theoccasion of his 65th birthday.