As an alternative for lithium-ion batteries(LIBs),sodium-ion batteries(SIBs)have lately received tremendous interest due to their abundant reserves as well as low cost.Nevertheless,the lack of suitable anode materials...As an alternative for lithium-ion batteries(LIBs),sodium-ion batteries(SIBs)have lately received tremendous interest due to their abundant reserves as well as low cost.Nevertheless,the lack of suitable anode materials severely hinders the application of sodium-ion batteries.TiS_(2)is elected as a representative material owing to its unique layered structure.But it always suffers from capacity fade due to poor electrochemical kinetics and structural stability.In this work,we fabricate a pre-potassiated TiS_(2)as a host material for sodium storage by an electrochemical pre-potassiation strategy.The intercalation/extraction mechanism,structural changes and reaction kinetics are completely investigated to reveal the outstanding electrochemical property of pre-potassiated TiS_(2)electrode.It turns out that the large interlayer space of pre-potassiated TiS_(2)is conducive to the diffusion of sodium ions,inducing the reduction of entropic barrier for the electrochemical reactions.In addition,the pre-potassiated host structure is still firmly maintained upon repeated cycles.Therefore,the pre-potassiated TiS_(2)presents superior rate capability(165.9 mA h g^(−1) at 1 C and 132.1 mA h g^(−1) at 20 C)and long-term cycling stability(85.3%capacity retention at 5 C after 500 cycles)for SIBs.This research provides an avenue to construct long-life sodium energy storage systems based on pre-potassiated TiS_(2).展开更多
Two-dimensional(2D) semiconductors have captured broad interest as light emitters, due to their unique excitonic effects. These layer-blocks can be integrated through van der Waals assembly, i.e., fabricating homo-or ...Two-dimensional(2D) semiconductors have captured broad interest as light emitters, due to their unique excitonic effects. These layer-blocks can be integrated through van der Waals assembly, i.e., fabricating homo-or heterojunctions, which show novel emission properties caused by interface engineering. In this review, we will first give an overview of the basic strategies that have been employed in interface engineering, including changing components, adjusting interlayer gap, and tuning twist angle. By modifying the interfacial factors, novel emission properties of emerging excitons are unveiled and discussed. Generally, well-tailored interfacial energy transfer and charge transfer within a 2D heterostructure cause static modulation of the brightness of intralayer excitons. As a special case, dynamically correlated dual-color emission in weakly-coupled bilayers will be introduced, which originates from intermittent interlayer charge transfer. For homobilayers and type Ⅱ heterobilayers, interlayer excitons with electrons and holes residing in neighboring layers are another important topic in this review. Moreover, the overlap of two crystal lattices forms moiré patterns with a relatively large period, taking effect on intralayer and interlayer excitons. Particularly, theoretical and experimental progresses on spatially modulated moiré excitons with ultra-sharp linewidth and quantum emission properties will be highlighted. Moiré quantum emitter provides uniform and integratable arrays of single photon emitters that are previously inaccessible, which is essential in quantum many-body simulation and quantum information processing. Benefiting from the optically addressable spin and valley indices, 2D heterostructures have become an indispensable platform for investigating exciton physics, designing and integrating novel concept emitters.展开更多
基金sponsored by NSAF joint Fund(U1830106)Science and Technology Innovation 2025 Major Program of Ningbo(2018B10061)+1 种基金National Natural Science Foundation of China(U1632114,51901205)K.C.Wong Magna Fund in Ningbo University。
文摘As an alternative for lithium-ion batteries(LIBs),sodium-ion batteries(SIBs)have lately received tremendous interest due to their abundant reserves as well as low cost.Nevertheless,the lack of suitable anode materials severely hinders the application of sodium-ion batteries.TiS_(2)is elected as a representative material owing to its unique layered structure.But it always suffers from capacity fade due to poor electrochemical kinetics and structural stability.In this work,we fabricate a pre-potassiated TiS_(2)as a host material for sodium storage by an electrochemical pre-potassiation strategy.The intercalation/extraction mechanism,structural changes and reaction kinetics are completely investigated to reveal the outstanding electrochemical property of pre-potassiated TiS_(2)electrode.It turns out that the large interlayer space of pre-potassiated TiS_(2)is conducive to the diffusion of sodium ions,inducing the reduction of entropic barrier for the electrochemical reactions.In addition,the pre-potassiated host structure is still firmly maintained upon repeated cycles.Therefore,the pre-potassiated TiS_(2)presents superior rate capability(165.9 mA h g^(−1) at 1 C and 132.1 mA h g^(−1) at 20 C)and long-term cycling stability(85.3%capacity retention at 5 C after 500 cycles)for SIBs.This research provides an avenue to construct long-life sodium energy storage systems based on pre-potassiated TiS_(2).
基金supported by the Natural Science Foundation of China(22203042,21873048 and 22173044)。
文摘Two-dimensional(2D) semiconductors have captured broad interest as light emitters, due to their unique excitonic effects. These layer-blocks can be integrated through van der Waals assembly, i.e., fabricating homo-or heterojunctions, which show novel emission properties caused by interface engineering. In this review, we will first give an overview of the basic strategies that have been employed in interface engineering, including changing components, adjusting interlayer gap, and tuning twist angle. By modifying the interfacial factors, novel emission properties of emerging excitons are unveiled and discussed. Generally, well-tailored interfacial energy transfer and charge transfer within a 2D heterostructure cause static modulation of the brightness of intralayer excitons. As a special case, dynamically correlated dual-color emission in weakly-coupled bilayers will be introduced, which originates from intermittent interlayer charge transfer. For homobilayers and type Ⅱ heterobilayers, interlayer excitons with electrons and holes residing in neighboring layers are another important topic in this review. Moreover, the overlap of two crystal lattices forms moiré patterns with a relatively large period, taking effect on intralayer and interlayer excitons. Particularly, theoretical and experimental progresses on spatially modulated moiré excitons with ultra-sharp linewidth and quantum emission properties will be highlighted. Moiré quantum emitter provides uniform and integratable arrays of single photon emitters that are previously inaccessible, which is essential in quantum many-body simulation and quantum information processing. Benefiting from the optically addressable spin and valley indices, 2D heterostructures have become an indispensable platform for investigating exciton physics, designing and integrating novel concept emitters.
