Effective direct recycling of inhomogeneously aged Li-ion battery cathode active materials

There is growing interest in lithium ion battery materials recycling, and specifically direct recycling, wherein the cathode material is harvested and rejuvenated for use in new batteries. A key risk associated with this process is the fact that materials collected from aged batteries will be inhomogeneous due to the variable experience they incur during use, both between cells and even within cells themselves. In this paper, we investigate the direct recycling process factors that address the effect of three properties of aged and harvested LiNi0.815Co0.15Al0.035O2 (NCA) materials: variation of state-of-charge (SoC), the inconsistent existence of a surface reconstruction layer on the material, and the inhomogeneous growth of the solid electrolyte interface (SEI). We will explore how each property impacts the consistency of the recycled NCA in terms of several key materials properties.