This study introduces a sustainable and environmentally friendly process for selective co-extraction of Ni2+ and Co2+

from leaching solution of spent ternary lithium-ion batteries (LIBs) with neodecanoic acid (V10). The extraction conditions

were systematically optimized, and a process for reducing extractant dissolution loss in the raffinate was specifically

designed, with both the extraction and extractant recovery steps integrated into a continuous mixer-settler operation.

Experimental results showed that under optimal conditions, the extraction efficiency of Ni and Co consistently 

exceeded 99.9%, and the concentrations of Li and Mg in the strip solution remained below 1 mg/L. This process 

achieved both ultra-high extraction of Ni and Co and deep separation from Mg and Li. Furthermore, the chemical 

oxygen demand (COD) of the raffinate was reduced from around 10,000 mg/L to below 1,000 mg/L, demonstrating the 

effectiveness of this method in significantly decreasing COD. In addition, the extraction mechanism and the mechanism 

for reducing extractant dissolution loss were also verified. This work provides insights for developing a potentially 

practical process based on the V10 extraction system to improve selective co-extraction of Ni and Co from complex 

solutions while reducing extractant dissolution loss.