Analysis of NCM concentration and extraction efficiency in the lithium-ion battery extraction process

Abstract

In recent years, with the increasing popularity of portable electronic devices (PEDs) and electric vehicles (EVs), the demand for lithium-ion batteries (LIBs) has continued to expand; however, the supply of raw materials such as nickel cobalt, and manganese (NCM) is limited, and it is essential to develop efficient recycling technologies. Hydrometallurgical methods, particularly extraction processes, can be used to obtain high-grade recycled LIB products with proper control of the process window. This study focused on the separation of NCM from copper (Cu) and aluminum (Al) by diluting the metal concentrations ([Me]) and adjusting the pH (using NH4OH) during extraction. For metal composition analysis, in addition to using inductively coupled plasma mass spectrometry (ICP-MS), ultraviolet–visible (UV–Vis) spectroscopy and colorimetric analysis were also employed to monitor ion concentrations. The change in solution color is directly related to the nickel (Ni) and cobalt (Co) ion concentrations. Moreover, a continuous shift in the Ni ion absorption spectra at different pH values did not occur for the Co ion absorption spectra. According to the extraction efficiency (EE%) results, the lower [Me] resulted in the higher EE% of NCM. The optimal process window was established within the range of 0.025–0.1 M and pH = 6.5–7.4.