The cathode of lithium-oxygen(Li-O_(2))batteries should have large space for high Li_(2)O_(2) uptake and superior electrocatalytic activity to oxygen evolution/reduction for long lifespan.Herein,a high-performance MnO...The cathode of lithium-oxygen(Li-O_(2))batteries should have large space for high Li_(2)O_(2) uptake and superior electrocatalytic activity to oxygen evolution/reduction for long lifespan.Herein,a high-performance MnO_(x)/hCNC cathode was constructed by the defect-induced deposition of manganese oxide(MnOx)nanoparticles on hierarchical carbon nanocages(hCNC).The corresponding Li-O2 battery(MnOx/hCNC@Li-O_(2))exhibited excellent electrocatalytic activity with the low overpotential of 0.73-0.99 V in the current density range of 0.1-1.0 A·g^(-1).The full discharge capacity and cycling life of MnO_(x)/hCNC@Li-O_(2) were increased by~86.7%and~91%,respectively,compared with the hCNC@Li-O_(2) counterpart.The superior performance of MnO_(x)/hCNC cathode was ascribed to(i)the highly dispersed MnO_(x) nanoparticles for boosting the reversibility of oxygen evolution/reduction reactions,(ii)the interconnecting pore structure for increasing Li_(2)O_(2) accommodation and facilitating charge/mass transfer,and(iii)the concealed surface defects of hCNC for suppressing side reactions.This study demonstrated an effective strategy to improve the performance of Li-O_(2) batteries by constructing cathodes with highly dispersed catalytic sites and hierarchical porous structure.展开更多
In the field of perovskite solar cells(PSCs),the research on defects in the buried interface has been relatively limited due to its non-exposure;however,this interface significantly impacts the performance enhancement...In the field of perovskite solar cells(PSCs),the research on defects in the buried interface has been relatively limited due to its non-exposure;however,this interface significantly impacts the performance enhancement of inverted PSCs.This study employs phenylethylammonium chloride(PEACl)molecules as a buffer layer to modify the buried interface of p-i-n structured PSCs,aiming to enhance the uniformity of self-assembled monolayers(SAMs)and facilitate the uniform nucleation and growth of perovskite films on the substrate.Furthermore,the introduction of the PEACl buffer layer effectively passivates defects at the bottom of the perovskite layer and notably enhances the crystal quality of the perovskite film by mitigating residual stress,thereby reducing nonradiative recombination loss.Following these optimizations,the MA-free PSCs treated with PEACl achieve a power conversion efficiency(PCE)of 24.11%,with significant improvements in storage,thermal stability,and operational stability.Particularly noteworthy is the device's performance in an unencapsulated state,whereas after 1,500 hours of continuous light operation stability testing,it retains 97%of its original efficiency.This study not only enriches the systematic understanding of the characteristics of the buried interface in PSCs but also contributes significantly to advancing the commercial production of perovskite photovoltaic technology.展开更多
The indiscriminate utilization of nondegradable polyethylene terephthalate(PET)-based products has triggered serious environmental pollution that has to be resolved vigorously.A simple synthesis of N-doped carbon nano...The indiscriminate utilization of nondegradable polyethylene terephthalate(PET)-based products has triggered serious environmental pollution that has to be resolved vigorously.A simple synthesis of N-doped carbon nanotubes from recycled PET(NCNTs_(r-PET))was developed by a nitric acid-assisted hydrothermal method.Experimental results and theoretical calculations show that the intrinsic defects in CNTs_(r-PET)would induce N-doping by NH_(3)generated from nitric acid during the hydrothermal process,thus producing the NCNTs_(r-PET).The life cycle assessment proves that the developed method for N-doped CNTs using r-PET as the carbon source is more environmentally friendly than the conventional chemical vapor deposition using acetylene as the carbon source.As a typical application,the NCNTs_(r-PET)delivered an impressive sodium storage capacity with an ultralong lifespan.This work not only provides a new route to upcycling waste plastics into valuable carbonaceous materials in an ecofriendly manner,but also reveals a basic understanding of the N-doping mechanism in carbonaceous materials.展开更多
The controllable synthesis of complicated nanostructures in advanced two-dimensional(2D)semiconductors,such as periodic regular hole arrays,is essential and remains immature.Here,we report a green,facile,highly contro...The controllable synthesis of complicated nanostructures in advanced two-dimensional(2D)semiconductors,such as periodic regular hole arrays,is essential and remains immature.Here,we report a green,facile,highly controlled synthetic method to efficiently pattern 2D semiconductors,such as periodic regular hexagonal-shaped hole arrays(HHA),in 2D-TMDs.Combining the production of artificial defect arrays through laser irradiation with anisotropic annealing etching,we created HHA with different arrangements,controlled hole sizes,and densities in bilayer WS_(2).Atomic force microscopy(AFM),Raman,photoluminescence(PL),and scanning transmission electron microscopy(STEM)characterization show that the 2D semiconductors have high quality with atomical clean and sharp edges as well as undamaged crystals in the unetched region.Furthermore,other nanostructures,such as nanoribbons and periodic regular triangular-shaped 2D-TMD arrays,can be fabricated.This kind of 2D semiconductors fabrication strategy is general and can be extended to a series of 2D materials.Density functional theory(DFT)calculations show that one WS_(2)molecule from the edges of the laser-irradiated holed region exhibits a robust etching activation,making selective etching at the artificial defects and the fabrication of regular 2D semiconductors possible.展开更多
基金This work was jointly financed by the National Key Research and Development Program of China(Nos.2018YFA0209100 and 2017YFA0206500)the National Natural Science Foundation of China(NSFC)(Nos.21832003,21972061,and 21773111)the Fundamental Research Funds for the Central Universities(No.020514380237)。
文摘The cathode of lithium-oxygen(Li-O_(2))batteries should have large space for high Li_(2)O_(2) uptake and superior electrocatalytic activity to oxygen evolution/reduction for long lifespan.Herein,a high-performance MnO_(x)/hCNC cathode was constructed by the defect-induced deposition of manganese oxide(MnOx)nanoparticles on hierarchical carbon nanocages(hCNC).The corresponding Li-O2 battery(MnOx/hCNC@Li-O_(2))exhibited excellent electrocatalytic activity with the low overpotential of 0.73-0.99 V in the current density range of 0.1-1.0 A·g^(-1).The full discharge capacity and cycling life of MnO_(x)/hCNC@Li-O_(2) were increased by~86.7%and~91%,respectively,compared with the hCNC@Li-O_(2) counterpart.The superior performance of MnO_(x)/hCNC cathode was ascribed to(i)the highly dispersed MnO_(x) nanoparticles for boosting the reversibility of oxygen evolution/reduction reactions,(ii)the interconnecting pore structure for increasing Li_(2)O_(2) accommodation and facilitating charge/mass transfer,and(iii)the concealed surface defects of hCNC for suppressing side reactions.This study demonstrated an effective strategy to improve the performance of Li-O_(2) batteries by constructing cathodes with highly dispersed catalytic sites and hierarchical porous structure.
基金supported by the Fundamental Research Funds for the Central Universities(2024YJS192)the National Natural Science Foundation of China(62174011)。
文摘In the field of perovskite solar cells(PSCs),the research on defects in the buried interface has been relatively limited due to its non-exposure;however,this interface significantly impacts the performance enhancement of inverted PSCs.This study employs phenylethylammonium chloride(PEACl)molecules as a buffer layer to modify the buried interface of p-i-n structured PSCs,aiming to enhance the uniformity of self-assembled monolayers(SAMs)and facilitate the uniform nucleation and growth of perovskite films on the substrate.Furthermore,the introduction of the PEACl buffer layer effectively passivates defects at the bottom of the perovskite layer and notably enhances the crystal quality of the perovskite film by mitigating residual stress,thereby reducing nonradiative recombination loss.Following these optimizations,the MA-free PSCs treated with PEACl achieve a power conversion efficiency(PCE)of 24.11%,with significant improvements in storage,thermal stability,and operational stability.Particularly noteworthy is the device's performance in an unencapsulated state,whereas after 1,500 hours of continuous light operation stability testing,it retains 97%of its original efficiency.This study not only enriches the systematic understanding of the characteristics of the buried interface in PSCs but also contributes significantly to advancing the commercial production of perovskite photovoltaic technology.
基金National Natural Science Foundation of China,Grant/Award Numbers:22109023,22179022,22209027Industry-University-Research Joint Innovation Project of Fujian Province,Grant/Award Number:2021H6006+2 种基金FuXiaQuan National Independent Innovation Demonstration Zone Collaborative Innovation Platform,Grant/Award Number:2022-P-027Youth Innovation Fund of Fujian Province,Grant/Award Numbers:2021J05043,2022J05046Science and Technology。
文摘The indiscriminate utilization of nondegradable polyethylene terephthalate(PET)-based products has triggered serious environmental pollution that has to be resolved vigorously.A simple synthesis of N-doped carbon nanotubes from recycled PET(NCNTs_(r-PET))was developed by a nitric acid-assisted hydrothermal method.Experimental results and theoretical calculations show that the intrinsic defects in CNTs_(r-PET)would induce N-doping by NH_(3)generated from nitric acid during the hydrothermal process,thus producing the NCNTs_(r-PET).The life cycle assessment proves that the developed method for N-doped CNTs using r-PET as the carbon source is more environmentally friendly than the conventional chemical vapor deposition using acetylene as the carbon source.As a typical application,the NCNTs_(r-PET)delivered an impressive sodium storage capacity with an ultralong lifespan.This work not only provides a new route to upcycling waste plastics into valuable carbonaceous materials in an ecofriendly manner,but also reveals a basic understanding of the N-doping mechanism in carbonaceous materials.
基金National Key R&D Program of the Ministry of Science and Technology of China,Grant/Award Number:2022YFA1203801The National Natural Science Foundation of China,Grant/Award Numbers:51991340,51991343,52221001,62174051+1 种基金The Hunan Key R&D Program Project,Grant/Award Number:2022GK2005Ningbo Natural Science Foundation,Grant/Award Number:2023J023。
文摘The controllable synthesis of complicated nanostructures in advanced two-dimensional(2D)semiconductors,such as periodic regular hole arrays,is essential and remains immature.Here,we report a green,facile,highly controlled synthetic method to efficiently pattern 2D semiconductors,such as periodic regular hexagonal-shaped hole arrays(HHA),in 2D-TMDs.Combining the production of artificial defect arrays through laser irradiation with anisotropic annealing etching,we created HHA with different arrangements,controlled hole sizes,and densities in bilayer WS_(2).Atomic force microscopy(AFM),Raman,photoluminescence(PL),and scanning transmission electron microscopy(STEM)characterization show that the 2D semiconductors have high quality with atomical clean and sharp edges as well as undamaged crystals in the unetched region.Furthermore,other nanostructures,such as nanoribbons and periodic regular triangular-shaped 2D-TMD arrays,can be fabricated.This kind of 2D semiconductors fabrication strategy is general and can be extended to a series of 2D materials.Density functional theory(DFT)calculations show that one WS_(2)molecule from the edges of the laser-irradiated holed region exhibits a robust etching activation,making selective etching at the artificial defects and the fabrication of regular 2D semiconductors possible.
