Direct regeneration of highly degraded LiNi0.6Co0.2Mn0.2O2 to high-performance single-crystalline cathodes
Zhenzhen Liu, Zongkun Bian, Heng Zhang, Xi Wu, Zhen Fu, Haimin Zhang, Guozhong Wang, Yunxia Zhang, Huijun Zhao
Abstract
The widespread popularization of electric vehicles and portable electronics gives rise to the concomitant surge of spent lithium-ion batteries (LIBs). Considering the resource shortage and environmental concerns, recycling degraded cathode materials is highly desirable to ensure the sustainable development of the whole LIBs industry. To this end, a facile LiBr-LiOH eutectic molten salt strategy is proposed for direct regeneration of highly degraded polycrystalline LiNi 0.6 Co 0.2 Mn 0.2 O 2 (denoted as D-NCM622), which enables efficient renovation of the nonstoichiometric composition and damaged crystal structure in D-NCM622, including full Li-supplement, complete restoration from rock salt/spinel phases to the original layered structure, suppressive cation disorder, and reconstructed single-crystalline nature. Benefiting from these favorable structural characteristics, the regenerated cathodes (R-NCM622) exhibit significantly enhanced electrochemical performance relative to D-NCM622, delivering an initial discharge capacity of 174.0 mAh g −1 at 0.2 C, capacity retention of 82.5 % after 200 cycles at 0.5 C, and excellent rate performance (136.7 mAh g −1 at 5 C), which is comparable to the fresh commercial NCM622 (C-NCM622). More significantly, the current regeneration route possesses the incomparable advantages in economic benefit and environmental impact compared to conventional recycling routes based on techno-economic analysis, ensuring sustainable recycling from highly degraded cathode materials.