Density Functional Theory Study of Selectivity of Crown Ethers to Li^+ in Spent Lithium-Ion Batteries Leaching Solutions

It is a challenge to recover lithium from the leaching solution of spent lithium-ion batteries,and crown ethers are potential extractants due to their selectivity to alkali metal ions.The theoretical calculations for the selectivity of crown ethers with different structures to Li ions in aqueous solutions were carried out based on the density functional theory.The calculated results of geometries,binding energies,and thermodynamic parameters show that 15C5 has the strongest selectivity to Li ions in the three crown ethers of 12C4,15C5,and 18C6.B15C5 has a smaller binding energy but more negative free energy than 15C5 when combined with Li^+,leading to that the lithium ions in aqueous solutions will combine with B15C5 rather than 15C5.The exchange reactions between B15C5 and hydrated Li^+,Co^2+,and Ni^2+were analyzed and the results show that B15C5 is more likely to capture Li^+from the hydrated ions in an aqueous solution containing Li^+,Co^2+,and Ni^2+.This study indicates that it is feasible to extract Li ions selectively using B15C5 as an extractant from the leaching solution of spent lithium-ion batteries.

Research status of peri-menopausal insomnia based on bibliometrics

Objective:To reflect the current situation and development level of the treatment of peri-menopausal insomnia,to provide ideas and basis for the treatment of peri-menopausal insomnia,and to lay a scientific foundation.Methods:The relevant literatures about peri-menopausal insomnia in the past 20 years from January 1,2000 to September 30,2020 were searched in full-text database,and the publication time distribution,periodical distribution and research types were statistically analyzed with the help of NoteExpress 4.2.0,Excel 2010 and UCINET 6.2 software.Bibliometrics and social network analysis were used to grasp the research status and research hotspots.Results:979 articles about insomnia in peri-menopausal period were included.The number of literatures showed an upward trend and decreased from 2018 to 2020.The top three journals are Inner Mongolia traditional Chinese Medicine,Guangming traditional Chinese Medicine and Sichuan traditional Chinese Medicine,with 30,25 and 22 articles respectively.A total of 1,846 authors participated in the publication.The top three authors were Hong Li(14,0.63%),Jun-Shan Huang(9,0.40%)and Ying Chen(9,0.40%).The social network map shows that“insomnia”,“peri-menopausal period”,“perimenopausal insomnia”,“peri-menopausal syndrome”,“traditional Chinese medicine therapy”and“acupuncture”are the research hotspots and have the strongest correlation.Conclusion:The number of articles about peri-menopausal insomnia shows a downward trend in recent years,and the“core author group”has not been formed.The clinical research in this field is relatively perfect,but a more complete theoretical system has not been formed yet.Most of the treatment of insomnia in peri-menopausal period is based on traditional Chinese medicine,which shows that traditional Chinese medicine is more effective in clinical use,and the curative effect of syndrome differentiation of traditional Chinese medicine has been affirmed.However,there are relative deficiencies,such as the lack of strict experimental research and evaluation standards,the lack of unilateral prescription research,and so on.Future researchers should pay more attention to the experimental research of traditional Chinese medicine in the treatment of peri-menopausal insomnia and unilateral empirical prescription research.