Utilization of Ni-rich NCM cathode material as oxidant to control manganese in Li-ion battery waste recycling

Manganese control is a crucial step in lithium-ion battery (LIB) recycling processes. Older cathode active materials (CAM) have manganese concentrations excessively high for modern high‑nickel cathode active materials. This study explores the use of the cathode active materials' oxidative properties for manganese removal during the leaching process utilizing synthetic solutions. Furthermore, delithiated cathode material was utilized to facilitate manganese removal from the NCM622 leachate. Preliminary experiments involved leaching various cathode materials in sulfuric acid without the addition of common reducing agent, such as H 2 O 2 . Results indicated that 35–50 wt-% of the transition metals could be leached from the cathode material in the absence of a reducing agent. Additionally, after approximately 90 wt-% of the lithium had been removed, manganese was effectively employed as a reducing agent for nickel and cobalt. A carefully controlled initial concentration of manganese sulfate achieved >99% leaching yield of Ni and Co, while precipitating MnO 2 with nickel and cobalt impurities below 1 wt-%. Moreover, Ni-rich cathode materials were successfully utilized to control Mn in the NMC622 recycling solution. Manganese removal efficiency was also studied using delithiated cathode materials at different lithium yields. Manganese removal yield was lower, if over 80% delithiation yield was obtained in separate delithiation reaction. • Mn control iscrucial in recycling high-Mn lithium-ion cathodes. • Oxidative CAMs enable Mn removal during leaching without reductant. • Delithiated CAMs enhance Mn removal from NCM622 leachate. • Mn selectively reduces Ni and Co after most lithium is removed. • Ni-rich CAMs improve Mn control in NCM622 recycling.