TY - GEN A1 - Meißner, André A1 - Sieber, Tim A1 - Acker, Jörg ED - Andresen, Birger ED - Rong, Harry ED - Tangstad, Merete ED - Tveit, Halvard ED - Page, Ingrid T1 - Lattice strain and phase transformations in silicon introduced by the precipitation of Cu3Si T2 - Silicon for the Chemical and Solar Industry XV N2 - The reaction of Si with CuCl was studied by a combination of Raman microscopy, confocal microscopy and SEM-EDX. Two reaction pathways were observed to proceed at the same time. The first one is a solid state reaction between Si and Cu or CuCl that leads to a massive nucleation of Cu3Si exactly at the interfacial contacts between CuCl and Si. This study shows how the presence of the Cu3Si phase can be clearly identified and distinguished from areas simply covered with copper by means of Raman microscopic measurements. The second reaction pathway identified proceeds via a short-range gas phase transport of CuCl at low temperatures. The immediate reaction of the transported CuCl to the Si surface causes the massive spread of Cu in the close neighborhood around the CuCl source particles, however, without a nucleation of Cu3Si. The nucleation of Cu3Si precipitates and the short-range transport of CuCl have a tremendous impact on the underlying Si matrix. Tensile- and compressive-strained Si are generated in the immediate vicinity of the precipitates and at their interface to the surrounding silicon. Indications of high-pressure modifications of Si were found. Those areas of the Si surface which are affected by the short-range transport of CuCl and covered with low concentrations of copper exhibit a significant tensile strain. As recently shown, tensile and compressive strain in Si have a significant impact on the reactivity of Si. It might be assumed that Cu3Si-induced lattice strain in Si affects the reactivity of Si in the Direct Reactions in a similar matter. KW - silicon KW - direct synthesis KW - copper silicide KW - cuprous chloride KW - Raman KW - lattice strain KW - reactivity Y1 - 2020 SN - 978-82-997357-9-7 SP - 47 EP - 56 PB - The Norwegian University of Science and Technology CY - Trondheim ER - TY - GEN A1 - Markowski, Jens A1 - Arellano-García, Harvey A1 - Meißner, André A1 - Acker, Jörg T1 - Comparative studies on the quality of recovered secondary graphites from the recycling of lithium-ion traction batteries T2 - Sustainable Minerals N2 - Automotive technology is increasingly determined by drives based on electric motors in combination with batteries. The lithium-ion traction battery is a storage medium that combines high electrical efficiency with compact dimensions and relatively low weight. For the recycling of the cathode coatings (esp. Ni, Mn, Co) and peripheral battery components a variety of recycling options already exist. The graphite coating of the anodes has hardly been the focus of research activities to date. State of the art is currently the melting of the complete Copper-anode foils including graphite coating, whereby the graphite contributes only as a carbon carrier to the recycling of the copper. Separation and reuse of the very high-quality graphite on an industrial scale has not yet taken place. At the BTU, a methodology has been developed, with which recovered anode graphites from traction batteries can be comprehensively characterised chemically and mechanically-physically. On this basis, targeted preparation for secondary applications is possible. The secondary graphites achieve a quality that allows them to be reused as second-use anode material and for other applications. KW - Graphitrecycling KW - Li-Ionen-Traction Batteries Y1 - 2023 UR - https://www.ceecthefuture.org/resource-center/comparative-studies-on-the-quality-of-recovered-secondary-graphites-from-the-recycling-of-lithium-ion-traction-batteries PB - Mining Engineering CY - Falmouth (UK) ER -