Bromine-based flow batteries(Br-FBs)are well suitable for stationary energy storage owing to their high energy density and low cost.However,their power density and lifespan are limited by relatively low reaction kinet...Bromine-based flow batteries(Br-FBs)are well suitable for stationary energy storage owing to their high energy density and low cost.However,their power density and lifespan are limited by relatively low reaction kinetics of Br_(2)/Br-couple and serious self-discharge caused by bromine migration.Herein,lamella-like porous carbon nitride nanosheets(PCNS)with adsorption and spatial confinement effects are used to modify cathodes for Br-FBs.The large specific surface area and plentiful N-containing groups enable PCNS with excellent adsorption capacity,which captures bromine species into the pores on PCNS layers.The captured bromine species is subsequently confined in PCNS interlayers due to the strong interaction between bromine species and N-containing groups,thus effectively depressing bromine diffusion/migration.Moreover,the strong bromine adsorption capacity significantly improves the electrochemical activity of PCNS.Consequently,a zinc-bromine flow battery(ZBFB)employing PCNS-modified cathode achieves a high current density of 180 m A cm^(-2),with an ultra-high coulombic efficiency of 99.22%.It also exhibits better self-discharge performance and a long cycle life of 500 cycles.Furthermore,a complexing agent-free ZBFB is successfully realized based on the superior bromineentrapping/retaining capacity of the PCNS-modified cathode.Consequently,this work provides a promising strategy toward electrode modifications for high-performance and long-lifespan Br-FBs.展开更多
The development of solid-state carbon dots with good photoluminescence performance both at room temperature and high temperature is still challenging.Herein,we apply a facile and rapid anti-solventinduced in situ recr...The development of solid-state carbon dots with good photoluminescence performance both at room temperature and high temperature is still challenging.Herein,we apply a facile and rapid anti-solventinduced in situ recrystallization where the carbon dots act as the seeds of heterogeneous nucleation to encapsulate them into barium chloride crystals.Benefiting from the spatial confinement effect of barium chloride,the carbon dots are well separated in the recrystallized barium chloride crystals,thereby inhibiting the non-radiative electron-electron energy interactions between the aggregated carbon dots,presenting a wide-spectrum(FWHM=107 nm)solid-state green-emission.Impressively,the carbon dot@barium chloride shows excellent photoluminescence thermal stability that at 423 K the intensity can maintain∼90%of the initial intensity at room temperature,due to the low electron-electron/electron-phonon non-radiative energy transfer between the carbon dots and barium chloride.Further,the practicability of solid-state carbon dot@barium chloride phosphors was demonstrated by a series of fabricated white light-emitting-diode prototypes,in which the increment in the wide-spectrum green phosphors improved the color rendering index of the prototypes from 78.6 to 89.1.The facile synthesis process and favorable photoluminescence features will shed light on the further development of environment-friendly carbon-dot-based composites for various solid-state optoelectronic devices.展开更多
基金supported by CAS Strategic Leading Science&Technology Program(A)(XDA21070100)CAS Engineering Laboratory for Electrochemical Energy Storage(KFJ-PTXM-027)+1 种基金DICP funding(DICP I202026 DICP I201928)Liaoning Natural Science Foundation(2021-MS-024)。
文摘Bromine-based flow batteries(Br-FBs)are well suitable for stationary energy storage owing to their high energy density and low cost.However,their power density and lifespan are limited by relatively low reaction kinetics of Br_(2)/Br-couple and serious self-discharge caused by bromine migration.Herein,lamella-like porous carbon nitride nanosheets(PCNS)with adsorption and spatial confinement effects are used to modify cathodes for Br-FBs.The large specific surface area and plentiful N-containing groups enable PCNS with excellent adsorption capacity,which captures bromine species into the pores on PCNS layers.The captured bromine species is subsequently confined in PCNS interlayers due to the strong interaction between bromine species and N-containing groups,thus effectively depressing bromine diffusion/migration.Moreover,the strong bromine adsorption capacity significantly improves the electrochemical activity of PCNS.Consequently,a zinc-bromine flow battery(ZBFB)employing PCNS-modified cathode achieves a high current density of 180 m A cm^(-2),with an ultra-high coulombic efficiency of 99.22%.It also exhibits better self-discharge performance and a long cycle life of 500 cycles.Furthermore,a complexing agent-free ZBFB is successfully realized based on the superior bromineentrapping/retaining capacity of the PCNS-modified cathode.Consequently,this work provides a promising strategy toward electrode modifications for high-performance and long-lifespan Br-FBs.
基金Science and Technology Research Project of Guangzhou(Grant No.201804010047)China Scholarship Council(Grant No.201908440070)Research Projects in Guangzhou University(Grant No.YG2020014)。
文摘The development of solid-state carbon dots with good photoluminescence performance both at room temperature and high temperature is still challenging.Herein,we apply a facile and rapid anti-solventinduced in situ recrystallization where the carbon dots act as the seeds of heterogeneous nucleation to encapsulate them into barium chloride crystals.Benefiting from the spatial confinement effect of barium chloride,the carbon dots are well separated in the recrystallized barium chloride crystals,thereby inhibiting the non-radiative electron-electron energy interactions between the aggregated carbon dots,presenting a wide-spectrum(FWHM=107 nm)solid-state green-emission.Impressively,the carbon dot@barium chloride shows excellent photoluminescence thermal stability that at 423 K the intensity can maintain∼90%of the initial intensity at room temperature,due to the low electron-electron/electron-phonon non-radiative energy transfer between the carbon dots and barium chloride.Further,the practicability of solid-state carbon dot@barium chloride phosphors was demonstrated by a series of fabricated white light-emitting-diode prototypes,in which the increment in the wide-spectrum green phosphors improved the color rendering index of the prototypes from 78.6 to 89.1.The facile synthesis process and favorable photoluminescence features will shed light on the further development of environment-friendly carbon-dot-based composites for various solid-state optoelectronic devices.
