Wang Yadong, Du Hao, Zhao Yun, Kang Yuqiong, Zhang Junhao, Xu Jiahui, Huang Yonglin, Jia Tianding, Chen Zhaoyang, Tavajohi Naser, Kang Feiyu, Li Baohua
Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
Department of Chemistry, Umeå University, 90187, Umeå, Sweden.
ChemSusChem. 2025 Jan 14;18(2):e202401458. doi: 10.1002/cssc.202401458. Epub 2024 Oct 25.
Complete discharge of spent lithium-ion batteries (LIBs) is a crucial step in LIB recycling, with the physical discharge method being particularly noted for its high discharge efficiency and environmental friendliness. However, previous studies and standards have focused on the performances of the discharge methods, neglecting the battery materials changes caused by discharge. Here we demonstrate that although prolonged discharge of spent batteries keeps the voltage around 0 V, an obvious current flow can be still observed, resulting from the dissolution and subsequent deposition of the copper foil. The deposited copper, primarily in the forms of Cu, CuO, and CuO, shows a gradient distribution on the surface of the anode and cathode active materials. This copper deposition significantly compromises the electrochemical performance of the discharged battery, with evident deterioration observed in the first charge-discharge capacity, cycling performance, and coulombic efficiency when compared to the original battery. This study provides guidance for the discharge methods and offers new insights into the materials failure mechanisms during discharge of spent batteries.
废旧锂离子电池（LIBs）的完全放电是LIB回收过程中的关键步骤，物理放电方法因其高放电效率和环境友好性而备受关注。然而，以往的研究和标准主要集中在放电方法的性能上，忽略了放电过程中电池材料的变化。在此，我们证明，尽管废旧电池长时间放电会使电压保持在0 V左右，但仍能观察到明显的电流，这是由铜箔的溶解和随后的沉积导致的。沉积的铜主要以Cu、CuO和Cu₂O的形式存在，在阳极和阴极活性材料表面呈现梯度分布。这种铜沉积显著损害了放电后电池的电化学性能，与原始电池相比，首次充放电容量、循环性能和库仑效率均出现明显恶化。本研究为放电方法提供了指导，并为废旧电池放电过程中的材料失效机制提供了新的见解。
