In this paper,aromatic nitroso compounds are investigated for their electrochemical performance as organic cathodes for lithium-ion batteries,with an elucidation of their redox mechanism.For the first time,ex situ spe...In this paper,aromatic nitroso compounds are investigated for their electrochemical performance as organic cathodes for lithium-ion batteries,with an elucidation of their redox mechanism.For the first time,ex situ spectroscopic analyses of small-molecule mono-nitroso compounds(including nitrosobenzene,2-nitrosotoluene,4-nitrosobenzoic acid,and lithium 4-nitrosobenzoate)reveal a universal,irreversible transformation of their nitroso dimers to azo species during the first electrochemical cycle,establishing azo groups as the true reversible redox-active centers.Unlike small-molecule analogs that convert rapidly,polymeric 1,4-dinitrosobenzene(DNsB)evolves gradually through azoxy intermediates,accompanied by increased conjugation and enhanced structural stability.To enhance utilization efficiency and cycling stability,DNSB is encapsulated in porous carbons(BP2000,Ketjenblack)via solution infusion,yielding composites with a high initial capacity of 383 mAh g^(-1)and a stable reversible capacity of 102 mAh g^(-1)after 800 cycles at 150 mA g^(-1).Electrochemical impedance spectroscopy confirms reduced charge-transfer resistance and improved interfacial stability.This work uncovers the fundamental nitroso-to-azo conversion mechanism and demonstrates a scalable carbon-confinement strategy to construct durable polymeric azo-type organic electrodes from nitroso compounds for sustainable energy storage.展开更多
基金financially supported by a grant awarded to Z. Y. from the Natural Science and Engineering Research Council (NSERC) of Canada (Grant # RGPIN-2020-05546)
文摘In this paper,aromatic nitroso compounds are investigated for their electrochemical performance as organic cathodes for lithium-ion batteries,with an elucidation of their redox mechanism.For the first time,ex situ spectroscopic analyses of small-molecule mono-nitroso compounds(including nitrosobenzene,2-nitrosotoluene,4-nitrosobenzoic acid,and lithium 4-nitrosobenzoate)reveal a universal,irreversible transformation of their nitroso dimers to azo species during the first electrochemical cycle,establishing azo groups as the true reversible redox-active centers.Unlike small-molecule analogs that convert rapidly,polymeric 1,4-dinitrosobenzene(DNsB)evolves gradually through azoxy intermediates,accompanied by increased conjugation and enhanced structural stability.To enhance utilization efficiency and cycling stability,DNSB is encapsulated in porous carbons(BP2000,Ketjenblack)via solution infusion,yielding composites with a high initial capacity of 383 mAh g^(-1)and a stable reversible capacity of 102 mAh g^(-1)after 800 cycles at 150 mA g^(-1).Electrochemical impedance spectroscopy confirms reduced charge-transfer resistance and improved interfacial stability.This work uncovers the fundamental nitroso-to-azo conversion mechanism and demonstrates a scalable carbon-confinement strategy to construct durable polymeric azo-type organic electrodes from nitroso compounds for sustainable energy storage.
