采用模板导向法和高温固相法制备尖晶石型八面体结构的Li Mn_2O_4锂离子电池正极材料,研究了该材料的结构和电化学性能。电化学性能研究表明,该电极材料具有良好的循环稳定性和倍率性能,在2.5~4.5 V电压范围,电流密度为100 m A/g时,首...采用模板导向法和高温固相法制备尖晶石型八面体结构的Li Mn_2O_4锂离子电池正极材料,研究了该材料的结构和电化学性能。电化学性能研究表明,该电极材料具有良好的循环稳定性和倍率性能,在2.5~4.5 V电压范围,电流密度为100 m A/g时,首周充放电比容量分别为147和179 m A·h/g,循环50周后,其充放电比容量仍分别保持在180/181 m A·h/g。优良的电化学性能可能归因于尖晶石Li Mn_2O_4的形貌结构特征,该方法为制备锂离子电池正极材料提供了思路和依据。展开更多
The development of new catalytic enantioselective access to stereogenic CF_(3)-containingmolecules is of great interest for expediting the discovery of lead compounds that remain challenging.Specifically,enantioselect...The development of new catalytic enantioselective access to stereogenic CF_(3)-containingmolecules is of great interest for expediting the discovery of lead compounds that remain challenging.Specifically,enantioselective synthesis of valuable ketones featuring stereogenicα-CF_(3) has rarely been reported.We devise a general and modular approach to facilely access enantioenrichedα-CF_(3) ketones via nickel-catalyzed reductive cross-coupling of readily available acid chlorides and racemicα-CF_(3) alkyl bromides in an enantioconvergent fashion under mild conditions.This protocol features neighboring directing group-free,high chemoselectivity,excellent functional group tolerance,facile scale-up,and notable amenability to straightforward downstream elaboration toward pharmaceutically useful enantioenrichedβ-trifluoromethylated secondary and tertiary alcohols,thus constituting a reliable,direct,practical,and efficient synthetic alternative to furnish enantiopureα-CF_(3) carbonyls.Interestingly,an appropriate choice of the phosphine ligand as coligand plays an important role in high efficiency and asymmetric induction.Mechanistic studies suggest a radical chain pathway.展开更多
文摘采用模板导向法和高温固相法制备尖晶石型八面体结构的Li Mn_2O_4锂离子电池正极材料,研究了该材料的结构和电化学性能。电化学性能研究表明,该电极材料具有良好的循环稳定性和倍率性能,在2.5~4.5 V电压范围,电流密度为100 m A/g时,首周充放电比容量分别为147和179 m A·h/g,循环50周后,其充放电比容量仍分别保持在180/181 m A·h/g。优良的电化学性能可能归因于尖晶石Li Mn_2O_4的形貌结构特征,该方法为制备锂离子电池正极材料提供了思路和依据。
基金We gratefully acknowledge funding from the Jiangsu Specially Appointed Professor Plan,National Natural Science Foundation of China(grant no.22071111)Natural Science Foundation of Jiangsu Province of China(grant no.BK20201368).
文摘The development of new catalytic enantioselective access to stereogenic CF_(3)-containingmolecules is of great interest for expediting the discovery of lead compounds that remain challenging.Specifically,enantioselective synthesis of valuable ketones featuring stereogenicα-CF_(3) has rarely been reported.We devise a general and modular approach to facilely access enantioenrichedα-CF_(3) ketones via nickel-catalyzed reductive cross-coupling of readily available acid chlorides and racemicα-CF_(3) alkyl bromides in an enantioconvergent fashion under mild conditions.This protocol features neighboring directing group-free,high chemoselectivity,excellent functional group tolerance,facile scale-up,and notable amenability to straightforward downstream elaboration toward pharmaceutically useful enantioenrichedβ-trifluoromethylated secondary and tertiary alcohols,thus constituting a reliable,direct,practical,and efficient synthetic alternative to furnish enantiopureα-CF_(3) carbonyls.Interestingly,an appropriate choice of the phosphine ligand as coligand plays an important role in high efficiency and asymmetric induction.Mechanistic studies suggest a radical chain pathway.
