Self‐Reconstruction of Highly Degraded LiNi0.8Co0.1Mn0.1O2 toward Stable Single‐Crystalline Cathode

• Published in: Advanced materials (Weinheim) Vol. 36; no. 5
• Main Authors: Qin, Zuoyu, Zhang, Tao, Gao, Xuesong, Luo, Wuqing, Han, Junwei, Lu, Bingan, Zhou, Jiang, Chen, Gen
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.02.2024
• Subjects: batteries recycling; Cathodes; Electrode materials; Lattice vacancies; LiOH‐NaCl system; Lithium-ion batteries; Molten salts; Recrystallization; Recycled materials; Recycling; single‐crystalline; spent LiNi0.8Co0.1Mn0.1O2; Structural stability
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202307091

The ever‐growing demand for resources sustainability has promoted the recycle of spent lithium‐ion batteries to a strategic position. Direct recycle outperforms either hydrometallurgical or pyrometallurgical approaches due to the high added value and facile treatment processes. However, the traditional direct recycling technologies are only applicable for Ni‐poor/middle cathodes. Herein, spent Ni‐rich LiNi0.8Co0.1Mn0.1O2 (S‐NCM) to performance‐enhanced single‐crystalline cathode materials is directly recycled using a simple but effective LiOH‐NaCl molten salt. The evolution process of the Li‐supplement and grain‐recrystallization during regeneration is systematically investigated, and the successful recovery of the highly degraded microstructure is comprehensively proven, including significant elimination of Ni2+ and O vacancies. Beneficial from the favorable reconstructed single‐crystalline particles, the regenerated NCM (R‐NCM) represents remarkably enhanced structural stability, electrochemical activity, O2 and cracks suppression during charge/discharge, thus achieving the excellent performances in long‐term cycling and high‐rate tests. As a result, R‐NCM maintains the 86.5% reversible capacity at 1 C after 200 cycles. Instructively, the present molten salt can be successfully applied for recycling spent NCMs with various Li and Ni compositions (e.g., LiNi0.5Co0.2Mn0.3O2). A simple but effective LiOH‐NaCl molten salt strategy is developed for recycling of highly degraded Ni‐rich cathode (LiNi0.8Co0.1Mn0.1O2) to performance‐enhanced single‐crystalline cathodes. The structural and chemical evolution during the recycling process is revealed. Meanwhile, this approach can also be successfully extended to recycle other cathode materials with varied Li and Ni compositions.