Ling Xin,Meng Ning,Ruimei Xu,Zhijian Huang,Yukai Hua,Xiao Yu,Yong Liu
The closed-loop recovery of valuable metals from spent lithium-ion battery (LIB) cathodes and their regeneration into high-performance cathodes are crucial for resource efficiency. However, conventional closed-loop processes use acids for leaching and strong alkalis for coprecipitation, which prevents true integration. Here, a cascading closed-loop strategy is proposed to leach metal ions from the spent LiNi0.5Co0.2Mn0.3O2 (NCM523) ternary material using organic acid and then produce NCM523 ternary material in the acidic leachate through a cation chelation and reassembly process. The entire process is carried out in an open vessel under ambient conditions within 40 min. The closed-loop process-derived NCM523 (CLP-NCM523) has the target stoichiometry and a one-dimensional quasi-single crystal structure, which enhances Li+ diffusion kinetics. The leaching efficiencies for Ni, Co, and Mn are 98.37%, 98.39%, and 99.43%, respectively, and the recovery efficiencies are 83.71%, 86.29%, and 81.61%, respectively. CLP-NCM523 cathodes exhibit superior electrochemical performance, particularly at high rates: 101.4 mA h g–1 at 10C (vs 69.5 mA h g–1 for commercial NCM523) and 86.7% capacity retention after 200 cycles. This strategy reduces the costs of converting acidic leachate to alkaline solution and avoids uneven element distribution in the precursor that occurs in coprecipitation-based closed-loop processes, demonstrating high potential for sustainable LIB recycling.
Inflammatory bowel disease (IBD) is characterized by the upregulation of reactive oxygen species (ROS) and dysfunction of gut immune system, and microbiota. The conventional treatments mainly focus on symptom control with medication by overuse of drugs. There is an urgent need to develop a closed-loop strategy that combines in situ monitoring and precise treatment. Herein, we innovatively designed the ‘cluster munition structure’ theranostic microgels to realize the monitoring and therapy for ulcerative colitis (a subtype of IBD). The superoxide anion specific probe (tetraphenylethylene-coelenterazine, TPC) and ROS-responsive nanogels consisting of postbiotics urolithin A (UA) were loaded into alginate and ion-crosslinked to obtain the theranostic microgels. The theranostic microgels could be delivered to the inflammatory site, where the environment-triggered breakup of the microgels and release of the nanogels were achieved in sequence. The TPC-UA group had optimal results in reducing inflammation, repairing colonic epithelial tissue, and remodeling microbiota, leading to inflammation amelioration and recovery of tight junction between the colonic epithelium, and maintenance of gut microbiota. During the recovery process, the local chemiluminescence intensity, which is proportional to the degree of inflammation, was gradually inhibited. The cluster munition of theranostic microgels displayed promising outcomes in monitoring inflammation and precise therapy, and demonstrated the potential for inflammatory disease management.
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