Langner Thomas, Sieber Tim, Acker Jörg
Department of Physical Chemistry, Brandenburg University of Technology Cottbus-Senftenberg, 01968, Senftenberg, Germany.
Sci Rep. 2021 Mar 18;11(1):6316. doi: 10.1038/s41598-021-85575-x.
End-of-life lithium-ion batteries represent an important secondary raw material source for nickel, cobalt, manganese and lithium compounds in order to obtain starting materials for the production of new cathode material. Each process step in recycling must be performed in such a way contamination products on the cathode material are avoided or reduced. This paper is dedicated to the first step of each recycling process, the deep discharge of lithium-ion batteries, as a prerequisite for the safe opening and disassembling. If pouch cells with different states of charge are connected in series and deep-discharged together, copper deposition occurs preferably in the cell with the lower charge capacity. The current forced through the cell with a low charge capacity leads, after lithium depletion in the anode and the collapse of the solid-electrolyte-interphase (SEI) to a polarity reversal in which the copper collector of the anode is dissolved and copper is deposited on the cathode surface. Based on measurements of the temperature, voltage drop and copper concentration in the electrolyte at the cell with the originally lower charge capacity, the point of dissolution and incipient deposition of copper could be identified and a model of the processes during deep discharge could be developed.
报废锂离子电池是镍、钴、锰和锂化合物的重要二次原料来源，可用于获取生产新型阴极材料的起始原料。回收过程中的每个工艺步骤都必须以避免或减少阴极材料上的污染产物的方式进行。本文致力于每个回收过程的第一步，即锂离子电池的深度放电，这是安全打开和拆解的前提条件。如果将不同荷电状态的软包电池串联并一起深度放电，铜沉积优选发生在荷电容量较低的电池中。在阳极锂耗尽且固体电解质界面（SEI）崩溃后，通过荷电容量低的电池强制通过的电流会导致极性反转，其中阳极的铜集流体溶解，铜沉积在阴极表面。基于对最初荷电容量较低的电池中电解质的温度、电压降和铜浓度的测量，可以确定铜的溶解点和初始沉积点，并建立深度放电过程的模型。
