Regeneration of Nickel-Rich LiNi _0.8 Co _0.1 Mn _0.1 O ₂ Cathode from Spent LiNi _0.5 Co _0.2 Mn _0.3 O ₂ by Low-Carbon and Economical Calcination and Coprecipitation

Recycling spent LiNixCoyMn1–x–yO2 cathode materials has gained significant attention, owing to its cost efficiency and environmental benefits. Nevertheless, several challenges persist, such as complex recycling processes, high costs, and the limited integration of recycling and regeneration technologies. This study proposes a solid-phase sintering approach to recycle the spent LiNi0.5Co0.2Mn0.3O2 (NCM523) material into LiNi0.8Co0.1Mn0.1O2 (NCM811) through an (NH4)2SO4-assisted calcination and coprecipitation (NS-CC) strategy. The NS-CC strategy not only simplifies recycling procedures by avoiding the complex element separation but also achieves a high material recovery rate. At a calcination temperature of 350 °C, recovery rates of Ni, Co, Mn, and Li reach approximately 99%. Under optimal regeneration conditions (pH 11.3 and presintering temperature of 470 °C), the regenerated NCM811 cathode exhibits a high specific capacity of 186.64 mAh·g–1 at 0.1 C, with excellent cycling performance and capacity retention of 85 and 70% after 100 and 200 cycles, respectively. Life cycle assessment and techno-economic analysis demonstrate that the NS-CC strategy exhibits minimal energy consumption, lower CO2 emissions, and high economic viability. This work offers a practical solution for efficiently recycling the spent NCM523 cathode materials and regenerating them into nickel-rich NCM811, advancing the sustainable development of lithium-ion batteries.