Cathode Upcycling for Direct Recycling Using a Rapid Coprecipitation Approach

In line with carbon neutrality goals by 2050, the Li-ion battery market has surged. To enhance battery sustainability and circularity, direct recycling methods aim to recover intact cathode materials. However, end-of-life cathode materials are typically 15-20 years old and often have lower energy density compared to current cathode materials. In response, we have developed a rapid coprecipitation process to boost energy density by converting low Ni-compositions, LiNi_0.33Co_0.33Mn_0.33O₂ (NMC111), into higher Ni-compositions (NMC622). This process forms a Ni-rich coating that diffuses into the core, increasing compositional homogeneity upon high-temperature relithiation. Our technology leverages existing infrastructure, offering low capital cost and minimal additional chemical input. Through ex-situ tomographic transmission X-ray microscopy (TXM) and XANES, we quantify Ni:Co:Mn elemental ratios and Ni valence state, confirming that elemental content evens at the secondary particle level, but elemental gradients remain at the primary particle level upon relithiation. Ex-situ high-resolution and in-situ wide-angle X-ray diffraction reveals concurrent structural changes during the relithiation process. These findings guide further improvements in synthesis for increased initial capacity and retention.