Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(gen...Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(generally 5%–10%)during Li^(+)storage causes unsatisfactory long-term cyclability.Here,“zero-strain”NiNb_(2)O_(6) fibers are explored as a new anode material with comprehensively good electrochemical properties.During Li^(+)storage,the expansion of electrochemical inactive NiO_(6) octahedra almost fully offsets the shrinkage of active NbO_(6) octahedra through reversible O movement.Such superior volume-accommodation capability of the NiO_(6) layers guarantees the“zero-strain”behavior of NiNb_(2)O_(6) in a broad temperature range(0.53%//0.51%//0.74%at 25//−10//60℃),leading to the excellent cyclability of the NiNb_(2)O_(6) fibers(92.8%//99.2%//91.1%capacity retention after 1000//2000//1000 cycles at 10C and 25//−10//60℃).This NiNb_(2)O_(6) material further exhibits a large reversible capacity(300//184//318 mAh g−1 at 0.1C and 25//−10//60℃)and outstanding rate performance(10 to 0.5C capacity percentage of 64.3%//50.0%//65.4%at 25//−10//60℃).Therefore,the NiNb_(2)O_(6) fibers are especially suitable for large-capacity,fast-charging,long-life,and all-climate lithium-ion batteries.展开更多
As a representative transition metal dichalcogenides(TMD),NiTe_(2)has an ultra-fast optical response,high carrier mobility,and excellent environmental stability.It has a broad application prospect in the fields of ene...As a representative transition metal dichalcogenides(TMD),NiTe_(2)has an ultra-fast optical response,high carrier mobility,and excellent environmental stability.It has a broad application prospect in the fields of ener-gy,biomedicine,optoelectronic devices,and so on.At present,there have been scant reports on the application of NiTe_(2)in the field of ultrafast photonics.In this work,NiTe_(2)was synthesized by chemical vapor deposition(CVD)and integrated with a tapered optical fiber to achieve mode-locking in an erbium-doped fiber laser(EDFL)and a thu-lium-doped fiber laser(TDFL).The mode-locked EDFL exhibited a pulse width of 678 fs and an output power of 3.92 mW.The pulse width of mode-locked TDFL was estimated to have a pulse width of 694 fs with an output power of 21.64 mW.These results demonstrate that NiTe_(2)is an effective saturable absorber material with potential applica-tions in the field of ultrafast optics.展开更多
Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection...Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection applications.Additionally,their commendable secondary processing characteristics enable the development of diverse composite materials when integrated with other materials,significantly broadening the potential utilization of ThO_(2)materials and thorium resources in industrial fields.In this work,the ThO_(2)fiber was fabricated by the sol-gel precursor method,and the precursor with good spinnability and excellent stability was synthesized for the first time.The ThO_(2)fiber with a mean diameter of 868 nm is both highly flexible and strong(max.tensile strength 2.21 MPa),capable of bending freely across a wide temperature range from-196℃(in liquid nitrogen)to 1200℃.Meanwhile,it exhibits excellent temperature stability and heat insulation properties.The ThO_(2)nanofiber membranes with layered structure have low density(32-37 mg·cm^(-3)),low thermal conductivity(27.3-30.1 mW·m^(-1)·K^(-1)@25℃).The ThO_(2)nanofiber membranes with 15 mm thickness can reduce the temperature from 1200 to 282℃and maintain a high aspect ratio and bendability after 1200℃@90 min.The results show that the ThO_(2)fiber can be used as a new kind of high-temperature resistant material.展开更多
Chemical vapor deposition is the predominant method to prepare MgAl_(2)O_(4)fibers.However,it faces several challenges,including exorbitantly high reaction temperatures,substantial production costs,and relatively low ...Chemical vapor deposition is the predominant method to prepare MgAl_(2)O_(4)fibers.However,it faces several challenges,including exorbitantly high reaction temperatures,substantial production costs,and relatively low yields.In this study,porous MgAl_(2)O_(4)fibers were fabricated through a solid-state reaction method,utilizing MgSO_(4)·5Mg(OH)_(2)·3H_(2)O whiskers as templates,mixed with either aluminum sol orα-Al_(2)O_(3)micropowder.The impact of various parameters on the synthesis of porous MgAl_(2)O_(4)fibres was systematically investigated,including the heat treatment temperature(1000,1100 and 1300℃),the holding time(3 and 10 h)and the aluminum source(aluminum sol orα-Al_(2)O_(3)micropowder).The results reveal that:(1)in comparison with fibers synthesized usingα-Al_(2)O_(3)as the aluminum source,those prepared with aluminum sol exhibit a significantly higher generation amount of MgAl_(2)O_(4);(2)as the heat treatment temperature increases,Al_(2)O_(3)gradually reacts with MgO,continuously increasing the formation amount of porous MgAl_(2)O_(4)with small and uniformly distributed nanopores,and the synthesized porous MgAl_(2)O_(4)fibres have small and uniform nanopores;(3)the optimal synthesis process involves using aluminum sol as the aluminum source and firing at 1300℃ for 3 h.展开更多
High-performance Ti_(3)C_(2)T_(x)fibers have garnered significant potential for smart fibers enabled fabrics.Nonetheless,a major challenge hindering their widespread use is the lack of strong interlayer interactions b...High-performance Ti_(3)C_(2)T_(x)fibers have garnered significant potential for smart fibers enabled fabrics.Nonetheless,a major challenge hindering their widespread use is the lack of strong interlayer interactions between Ti_(3)C_(2)T_(x)nanosheets within fibers,which restricts their properties.Herein,a versatile strategy is proposed to construct wet-spun Ti_(3)C_(2)T_(x)fibers,in which trace amounts of borate form strong interlayer crosslinking between Ti_(3)C_(2)T_(x)nanosheets to significantly enhance interactions as supported by density functional theory calculations,thereby reducing interlayer spacing,diminishing microscopic voids and promoting orientation of the nanosheets.The resultant Ti_(3)C_(2)T_(x)fibers exhibit exceptional electrical conductivity of 7781 S cm^(-1)and mechanical properties,including tensile strength of 188.72 MPa and Young's modulus of 52.42 GPa.Notably,employing equilibrium molecular dynamics simulations,finite element analysis,and cross-wire geometry method,it is revealed that such crosslinking also effectively lowers interfacial thermal resistance and ultimately elevates thermal conductivity of Ti_(3)C_(2)T_(x)fibers to 13 W m^(-1)K^(-1),marking the first systematic study on thermal conductivity of Ti_(3)C_(2)T_(x)fibers.The simple and efficient interlayer crosslinking enhancement strategy not only enables the construction of thermal conductivity Ti_(3)C_(2)T_(x)fibers with high electrical conductivity for smart textiles,but also offers a scalable approach for assembling other nanomaterials into multifunctional fibers.展开更多
The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory ...The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory fibers.While the reticulospinal tract has been shown to be particularly prone to axonal growth and plasticity following injuries of the spinal cord,the differential capacities of excitatory and inhibitory fibers for plasticity remain unclear.As adaptive axonal plasticity involves a sophisticated interplay between excitatory and inhibitory input,we investigated in this study the plastic potential of glutamatergic(vGlut2)and GABAergic(vGat)fibers originating from the gigantocellular nucleus and the lateral paragigantocellular nucleus,two nuclei important for locomotor function.Using a combination of viral tracing,chemogenetic silencing,and AI-based kinematic analysis,we investigated plasticity and its impact on functional recovery within the first 3 weeks following injury,a period prone to neuronal remodeling.We demonstrate that,in this time frame,while vGlut2-positive fibers within the gigantocellular and lateral paragigantocellular nuclei rewire significantly following cervical spinal cord injury,vGat-positive fibers are rather unresponsive to injury.We also show that the acute silencing of excitatory axonal fibers which rewire in response to lesions of the spinal cord triggers a worsening of the functional recovery.Using kinematic analysis,we also pinpoint the locomotion features associated with the gigantocellular nucleus or lateral paragigantocellular nucleus during functional recovery.Overall,our study increases the understanding of the role of the gigantocellular and lateral paragigantocellular nuclei during functional recovery following spinal cord injury.展开更多
Dual-carbon batteries(DCBs)have emerged as an appealing candidate for large-scale energy storage,yet the common trade-off between active sites and electronic conduction in carbon materials engenders a main challenge t...Dual-carbon batteries(DCBs)have emerged as an appealing candidate for large-scale energy storage,yet the common trade-off between active sites and electronic conduction in carbon materials engenders a main challenge towards efficient DCBs.Here,we introduce a heteroatom-doped sp^(3) /sp^(2) hybridized carbon fiber membrane(cPAN-Gr)as a universal binder-free active electrode that effectively overcomes this trade-off,enabling efficient Li-ion intercalation chemistry for advanced DCBs.By strategically tuning the sp^(3) and sp^(2) carbon hybridization,the interlayer interaction,geometric and electronic structures of c PANGr are simultaneously optimized,which facilitates rapid Li-ion adsorption,smooth interlayer transport,and efficient electron transport by maximizing the synergy between sp^(2) -and sp^(3) -hybridized carbon.This,coupled with a 3D porous network structure,endows the c PAN-Gr with superior Li-ion storage capability and fast reaction kinetics.Therefore,the c PAN-Gr electrode delivers a high reversible capacity of 345 m A h g^(-1),excellent rate capability(50 C),and an ultralong cycle life over 10,000 cycles,outperforming other reported carbon-based electrodes.Moreover,the constructed DCB exhibits a large specific capacity of 135 m A h g^(-1),long-term cyclability over 500 cycles,and a remarkable energy density of 524.4 Wh kg^(-1).The c PAN-Gr electrode can also be expanded to construct a LiFePO_(4)//cPAN-Gr full battery.Combined theoretical and experimental studies reveal the crucial role of an optimized sp^(3) /sp^(2) ratio(79%)with topological defects and pyridine/pyrrolic N sites on the performance enhancement.This work offers new insights into the design of advanced carbon materials for DCBs and beyond.展开更多
基金supported by the National Natural Science Foundation of China(51762014,52231007,12327804,T2321003,22088101)in part by the National Key Research Program of China under Grant 2021YFA1200600.
文摘Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(generally 5%–10%)during Li^(+)storage causes unsatisfactory long-term cyclability.Here,“zero-strain”NiNb_(2)O_(6) fibers are explored as a new anode material with comprehensively good electrochemical properties.During Li^(+)storage,the expansion of electrochemical inactive NiO_(6) octahedra almost fully offsets the shrinkage of active NbO_(6) octahedra through reversible O movement.Such superior volume-accommodation capability of the NiO_(6) layers guarantees the“zero-strain”behavior of NiNb_(2)O_(6) in a broad temperature range(0.53%//0.51%//0.74%at 25//−10//60℃),leading to the excellent cyclability of the NiNb_(2)O_(6) fibers(92.8%//99.2%//91.1%capacity retention after 1000//2000//1000 cycles at 10C and 25//−10//60℃).This NiNb_(2)O_(6) material further exhibits a large reversible capacity(300//184//318 mAh g−1 at 0.1C and 25//−10//60℃)and outstanding rate performance(10 to 0.5C capacity percentage of 64.3%//50.0%//65.4%at 25//−10//60℃).Therefore,the NiNb_(2)O_(6) fibers are especially suitable for large-capacity,fast-charging,long-life,and all-climate lithium-ion batteries.
基金Supported by Guangdong Basic and Applied Basic Research Fund,China(2024A1515012429)。
文摘As a representative transition metal dichalcogenides(TMD),NiTe_(2)has an ultra-fast optical response,high carrier mobility,and excellent environmental stability.It has a broad application prospect in the fields of ener-gy,biomedicine,optoelectronic devices,and so on.At present,there have been scant reports on the application of NiTe_(2)in the field of ultrafast photonics.In this work,NiTe_(2)was synthesized by chemical vapor deposition(CVD)and integrated with a tapered optical fiber to achieve mode-locking in an erbium-doped fiber laser(EDFL)and a thu-lium-doped fiber laser(TDFL).The mode-locked EDFL exhibited a pulse width of 678 fs and an output power of 3.92 mW.The pulse width of mode-locked TDFL was estimated to have a pulse width of 694 fs with an output power of 21.64 mW.These results demonstrate that NiTe_(2)is an effective saturable absorber material with potential applica-tions in the field of ultrafast optics.
基金supported by the National Natural Science Foundation of China(No.52202090)the Fundamental Research Funds for the Central Universities(No.2082019014).
文摘Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection applications.Additionally,their commendable secondary processing characteristics enable the development of diverse composite materials when integrated with other materials,significantly broadening the potential utilization of ThO_(2)materials and thorium resources in industrial fields.In this work,the ThO_(2)fiber was fabricated by the sol-gel precursor method,and the precursor with good spinnability and excellent stability was synthesized for the first time.The ThO_(2)fiber with a mean diameter of 868 nm is both highly flexible and strong(max.tensile strength 2.21 MPa),capable of bending freely across a wide temperature range from-196℃(in liquid nitrogen)to 1200℃.Meanwhile,it exhibits excellent temperature stability and heat insulation properties.The ThO_(2)nanofiber membranes with layered structure have low density(32-37 mg·cm^(-3)),low thermal conductivity(27.3-30.1 mW·m^(-1)·K^(-1)@25℃).The ThO_(2)nanofiber membranes with 15 mm thickness can reduce the temperature from 1200 to 282℃and maintain a high aspect ratio and bendability after 1200℃@90 min.The results show that the ThO_(2)fiber can be used as a new kind of high-temperature resistant material.
文摘Chemical vapor deposition is the predominant method to prepare MgAl_(2)O_(4)fibers.However,it faces several challenges,including exorbitantly high reaction temperatures,substantial production costs,and relatively low yields.In this study,porous MgAl_(2)O_(4)fibers were fabricated through a solid-state reaction method,utilizing MgSO_(4)·5Mg(OH)_(2)·3H_(2)O whiskers as templates,mixed with either aluminum sol orα-Al_(2)O_(3)micropowder.The impact of various parameters on the synthesis of porous MgAl_(2)O_(4)fibres was systematically investigated,including the heat treatment temperature(1000,1100 and 1300℃),the holding time(3 and 10 h)and the aluminum source(aluminum sol orα-Al_(2)O_(3)micropowder).The results reveal that:(1)in comparison with fibers synthesized usingα-Al_(2)O_(3)as the aluminum source,those prepared with aluminum sol exhibit a significantly higher generation amount of MgAl_(2)O_(4);(2)as the heat treatment temperature increases,Al_(2)O_(3)gradually reacts with MgO,continuously increasing the formation amount of porous MgAl_(2)O_(4)with small and uniformly distributed nanopores,and the synthesized porous MgAl_(2)O_(4)fibres have small and uniform nanopores;(3)the optimal synthesis process involves using aluminum sol as the aluminum source and firing at 1300℃ for 3 h.
基金the support from the National Natural Science Foundation of China(52403112,52473083)Natural Science Basic Research Program of Shaanxi(2024JC-TBZC-04)+2 种基金the Innovation Capability Support Program of Shaanxi(2024RS-CXTD-57)Fundamental Research Funds for the Central Universities(D5000240062,D5000240077)Undergraduate Innovation&Business Program in Northwestern Polytechnical University(202410699041)。
文摘High-performance Ti_(3)C_(2)T_(x)fibers have garnered significant potential for smart fibers enabled fabrics.Nonetheless,a major challenge hindering their widespread use is the lack of strong interlayer interactions between Ti_(3)C_(2)T_(x)nanosheets within fibers,which restricts their properties.Herein,a versatile strategy is proposed to construct wet-spun Ti_(3)C_(2)T_(x)fibers,in which trace amounts of borate form strong interlayer crosslinking between Ti_(3)C_(2)T_(x)nanosheets to significantly enhance interactions as supported by density functional theory calculations,thereby reducing interlayer spacing,diminishing microscopic voids and promoting orientation of the nanosheets.The resultant Ti_(3)C_(2)T_(x)fibers exhibit exceptional electrical conductivity of 7781 S cm^(-1)and mechanical properties,including tensile strength of 188.72 MPa and Young's modulus of 52.42 GPa.Notably,employing equilibrium molecular dynamics simulations,finite element analysis,and cross-wire geometry method,it is revealed that such crosslinking also effectively lowers interfacial thermal resistance and ultimately elevates thermal conductivity of Ti_(3)C_(2)T_(x)fibers to 13 W m^(-1)K^(-1),marking the first systematic study on thermal conductivity of Ti_(3)C_(2)T_(x)fibers.The simple and efficient interlayer crosslinking enhancement strategy not only enables the construction of thermal conductivity Ti_(3)C_(2)T_(x)fibers with high electrical conductivity for smart textiles,but also offers a scalable approach for assembling other nanomaterials into multifunctional fibers.
基金supported by the Deutsche Forschungsgemeinschaft(DFG),TRR274(Project ID 408885537,Sy Nergy,EXC 2145/ID 390857198,to FMB)。
文摘The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory fibers.While the reticulospinal tract has been shown to be particularly prone to axonal growth and plasticity following injuries of the spinal cord,the differential capacities of excitatory and inhibitory fibers for plasticity remain unclear.As adaptive axonal plasticity involves a sophisticated interplay between excitatory and inhibitory input,we investigated in this study the plastic potential of glutamatergic(vGlut2)and GABAergic(vGat)fibers originating from the gigantocellular nucleus and the lateral paragigantocellular nucleus,two nuclei important for locomotor function.Using a combination of viral tracing,chemogenetic silencing,and AI-based kinematic analysis,we investigated plasticity and its impact on functional recovery within the first 3 weeks following injury,a period prone to neuronal remodeling.We demonstrate that,in this time frame,while vGlut2-positive fibers within the gigantocellular and lateral paragigantocellular nuclei rewire significantly following cervical spinal cord injury,vGat-positive fibers are rather unresponsive to injury.We also show that the acute silencing of excitatory axonal fibers which rewire in response to lesions of the spinal cord triggers a worsening of the functional recovery.Using kinematic analysis,we also pinpoint the locomotion features associated with the gigantocellular nucleus or lateral paragigantocellular nucleus during functional recovery.Overall,our study increases the understanding of the role of the gigantocellular and lateral paragigantocellular nuclei during functional recovery following spinal cord injury.
基金financial support from Guangdong Basic and Applied Basic Research Foundation(2020B1515420001and 2023B1515040027)Fundamental Research Funds for the Central Universities,Sun Yat-sen University(23yxqntd002)the Postdoctoral Fellowship Program of CPSF(GZC20242066)。
文摘Dual-carbon batteries(DCBs)have emerged as an appealing candidate for large-scale energy storage,yet the common trade-off between active sites and electronic conduction in carbon materials engenders a main challenge towards efficient DCBs.Here,we introduce a heteroatom-doped sp^(3) /sp^(2) hybridized carbon fiber membrane(cPAN-Gr)as a universal binder-free active electrode that effectively overcomes this trade-off,enabling efficient Li-ion intercalation chemistry for advanced DCBs.By strategically tuning the sp^(3) and sp^(2) carbon hybridization,the interlayer interaction,geometric and electronic structures of c PANGr are simultaneously optimized,which facilitates rapid Li-ion adsorption,smooth interlayer transport,and efficient electron transport by maximizing the synergy between sp^(2) -and sp^(3) -hybridized carbon.This,coupled with a 3D porous network structure,endows the c PAN-Gr with superior Li-ion storage capability and fast reaction kinetics.Therefore,the c PAN-Gr electrode delivers a high reversible capacity of 345 m A h g^(-1),excellent rate capability(50 C),and an ultralong cycle life over 10,000 cycles,outperforming other reported carbon-based electrodes.Moreover,the constructed DCB exhibits a large specific capacity of 135 m A h g^(-1),long-term cyclability over 500 cycles,and a remarkable energy density of 524.4 Wh kg^(-1).The c PAN-Gr electrode can also be expanded to construct a LiFePO_(4)//cPAN-Gr full battery.Combined theoretical and experimental studies reveal the crucial role of an optimized sp^(3) /sp^(2) ratio(79%)with topological defects and pyridine/pyrrolic N sites on the performance enhancement.This work offers new insights into the design of advanced carbon materials for DCBs and beyond.
