Neuromorphic devices that mimic the information processing function of biological synapses and neurons have attracted considerable attention due to their potential applications in brain-like perception and computing. ...Neuromorphic devices that mimic the information processing function of biological synapses and neurons have attracted considerable attention due to their potential applications in brain-like perception and computing. In this paper,neuromorphic transistors with W-doped In_(2)O_(3)nanofibers as the channel layers are fabricated and optoelectronic synergistic synaptic plasticity is also investigated. Such nanofiber transistors can be used to emulate some biological synaptic functions, including excitatory postsynaptic current(EPSC), long-term potentiation(LTP), and depression(LTD). Moreover, the synaptic plasticity of the nanofiber transistor can be synergistically modulated by light pulse and electrical pulse.At last, pulsed light learning and pulsed electrical forgetting behaviors were emulated in 5×5 nanofiber device array.Our results provide new insights into the development of nanofiber optoelectronic neuromorphic devices with synergistic synaptic plasticity.展开更多
High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface...High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance.Herein,the thin layer of two-dimensional(2D)graphitic carbon-nitride(g-C_(3)N_(4))is uniformly coated on the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(denoted as NCM811@CN)using a facile chemical vaporization-assisted synthesis method.As an ideal protective layer,the g-C_(3)N_(4)layer effectively avoids direct contact between the NCM811 cathode and the electrolyte,preventing harmful side reactions and inhibiting secondary crystal cracking.Moreover,the unique nanopore structure and abundant nitrogen vacancy edges in g-C_(3)N_(4)facilitate the adsorption and diffusion of lithium ions,which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode.As a result,the NCM811@CN-3wt%cathode exhibits 161.3 mAh g^(−1)and capacity retention of 84.6%at 0.5 C and 55°C after 400 cycles and 95.7 mAh g^(−1)at 10 C,which is greatly superior to the uncoated NCM811(i.e.129.3 mAh g^(−1)and capacity retention of 67.4%at 0.5 C and 55°C after 220 cycles and 28.8 mAh g^(−1)at 10 C).The improved cycle performance of the NCM811@CN-3wt%cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:LLZTO electrolyte membranes,which show 163.8 mAh g^(−1)and the capacity retention of 88.1%at 0.1 C and 30°C after 200 cycles and 95.3 mAh g^(−1)at 1 C.展开更多
N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers have been successfully synthesized according to a facile solvothermal/hydrothermal method. The obtained CNTs@α-Fe_2O_3@C nanofibers composites exhibited spe- cial three-di...N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers have been successfully synthesized according to a facile solvothermal/hydrothermal method. The obtained CNTs@α-Fe_2O_3@C nanofibers composites exhibited spe- cial three-dimensional （3-D） network structure, which endows they promising candidate for anode ma- terials of lithium ion battery. The coaxial property of CNTs@α-Fe_2O_3@C nanofibers could significantly improve the cycling and rate performance owing to the acceleration of charge/electron transfer, improve- ment of conductivity, maintaining of structural integrity and inhibiting the aggregation. The α-Fe_2O_3 nanoparticles with small size and high percentage of N-doped amount could further improve the elec- trochemical performance. As for the CNTs@α-Fe_2O_3@C nanofibers, the capacity presented a high value of 1255.4 mAh/g at 0.1 C, and retained at 1213.4 mAh/g after 60 cycles. Even at high rate of 5 C, the ca- pacity still exhibited as high as 319 mAh/g. The results indicated that the synthesized N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers exhibited high cvcling and rate oerformance.展开更多
Stable and high‐efficiency bifunctional catalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desired for the practical application of Li‐O_(2)batteries with excellent rate performanc...Stable and high‐efficiency bifunctional catalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desired for the practical application of Li‐O_(2)batteries with excellent rate performance and cycle stability.Herein,a novel hybrid bifunctional catalyst with carbon nanofibers inlaid with hollow Co_(3)O_(4)nanoparticles and separate active sites for ORR and OER were prepared and applied in Li‐O_(2)batteries.Benefiting from the synergistic effect of unique porous structural features and high electrocatalytic activity of hollow Co3O4 intimately bound to N‐doped carbon nanofibers,the assembled Li‐O_(2)batteries with novel catalyst exhibited high specific capacity,excellent rate capability,and cycle stability up to 150 cycles under a capacity limitation of 500 mAh g^(–1)at a current density of 100 mA g^(–1).The facile synthesis and preliminary results in this work show the as‐prepared catalyst as a promising bifunctional electrocatalyst for applications in metal‐air batteries,fuel cells,and electrocatalysis.展开更多
SnO_(2)/Co_(3)O_(4)nanofibers(NFs)are synthesized by using a homopolar electrospinning system with double jets of positive polarity electric fields.The morphology and structure of SnO_(2)/Co_(3)O_(4)hetero-nanofibers ...SnO_(2)/Co_(3)O_(4)nanofibers(NFs)are synthesized by using a homopolar electrospinning system with double jets of positive polarity electric fields.The morphology and structure of SnO_(2)/Co_(3)O_(4)hetero-nanofibers are characterized by using field emission scanning electron microscope(FE-SEM),transmission electron microscope(TEM),x-ray diffraction(XRD),and x-ray photoelectron spectrometer(XPS).The analyses of SnO_(2)/Co_(3)O_(4)NFs by EDS and HRTEM show that the cobalt and tin exist on one nanofiber,which is related to the homopolar electrospinning and the crystallization during sintering.As a typical n-type semiconductor,Sn O_(2)has the disadvantages of high optimal operating temperature and poor reproducibility.Comparing with Sn O_(2),the optimal operating temperature of SnO_(2)/Co_(3)O_(4)NFs is reduced from 350℃to 250℃,which may be related to the catalysis of Co_(2)O_(2).The response of SnO_(2)/Co_(3)O_(4)to 100-ppm ethanol at 250℃is 50.9,9 times higher than that of pure Sn O_(2),which may be attributed to the p–n heterojunction between the n-type Sn O_(2)crystalline grain and the p-type Co_(2)O_(2)crystalline grain.The nanoscale p–n heterojunction promotes the electron migration and forms an interface barrier.The synergy effects between Sn O_(2)and Co_(2)O_(2),the crystalline grain p–n heterojunction,the existence of nanofibers and the large specific surface area all jointly contribute to the improved gas sensing performance.展开更多
A thin PVA/FeCl_3 composite fiber was prepared by using sol-gel processing and electrospinning techniques. A nanofiber of α-Fe_2O_3 with the diameter of 50_150 nm was obtained via high temperature calcination of the ...A thin PVA/FeCl_3 composite fiber was prepared by using sol-gel processing and electrospinning techniques. A nanofiber of α-Fe_2O_3 with the diameter of 50_150 nm was obtained via high temperature calcination of the PVA/FeCl_3 composite fiber. The material was characterized by infra-red(IR) spectroscopy, X-ray diffraction(XRD), and scanning electron microscopy(SEM). The results show that the fiber after the calcination at 700 ℃ was a pure α-Fe_2O_3 nanofiber.展开更多
Supported γ-Al2O3 membranes without defects were prepared by the sol-gel procedure. The sol-gel method involved peptization of a boehmite (AlOOH) sol prepared from ammonium aluminium sulphate. The morphology of the s...Supported γ-Al2O3 membranes without defects were prepared by the sol-gel procedure. The sol-gel method involved peptization of a boehmite (AlOOH) sol prepared from ammonium aluminium sulphate. The morphology of the supported membranes was characterized by scanning electron microscopy (SEM) and 3D rotational microscopy. Furthermore, the effects of different preparing conditions on morphological characteristics of the membrane were also investigated. The results show that PVA is a good crack-preventing agent and the morphology of supported membranes is affected by many factors, such as Al2O3 and PVA contents of the sol, drying and sintering procedures and intrinsic defects on the substrate surface.展开更多
Considering the intrinsic advantages of natural copiousness and cost-effectiveness of potassium resource,potassium-ion batteries(KIBs) are booming as prospective alternatives to lithium-ion batteries(LIBs) in large-sc...Considering the intrinsic advantages of natural copiousness and cost-effectiveness of potassium resource,potassium-ion batteries(KIBs) are booming as prospective alternatives to lithium-ion batteries(LIBs) in large-scale energy storage scenarios. Nevertheless, lacking desirable electrodes for reversibly hosting the bulky K+hinders the widespread application of KIBs, and it needs to be urgently solved. Hereon, the porous S-doped Sb_(2)O_(3)-graphene-carbon(SAGC) nanofibers are manufactured through an adjustable and facile approach, which involves electrospinning, in situ etching and sulfuration. The synthesized SAGC is featured by the ultra-small amorphous Sb_(2)O_(3) homogeneously wrapped inside the carbon matrix, as well as the co-incorporation of graphene and sulfur. Tentatively,the SAGC nanofiber sheets are applied as binder-free anodes for KIBs, exhibiting a prominent cycling life(256.72 m Ah·g^(-1) over 150 cycles at 100 m A·g^(-1)) and rate·g^(-1) over 100 cycles at 1 A·g^(-1)). The positive synergy among all the active components accounts for the distinguished performances of the SAGC. By reinforcing the tolerability to the swelling stress, producing the valid electrochemical active sites, and promoting the charge transferring for reversible K+uptake, the SAGC finally renders the excellent cyclability, capacity, and rate capability. Moreover, the extrinsic electrochemical pseudocapacitance characteristics induced by the porous carbon substrate elevate the K-storage capacity of the SAGC as well. It is hoped that the conclusions drawn may offer new insights into a direction for the high-performance binderfree KIB anodes.展开更多
基金Project supported by the National Key Research and Development Program of China (Grant Nos. 2021YFA1200051 and 2019YFB2205400)the National Natural Science Foundation of China (Grant Nos. 62174082 and 62074075)。
文摘Neuromorphic devices that mimic the information processing function of biological synapses and neurons have attracted considerable attention due to their potential applications in brain-like perception and computing. In this paper,neuromorphic transistors with W-doped In_(2)O_(3)nanofibers as the channel layers are fabricated and optoelectronic synergistic synaptic plasticity is also investigated. Such nanofiber transistors can be used to emulate some biological synaptic functions, including excitatory postsynaptic current(EPSC), long-term potentiation(LTP), and depression(LTD). Moreover, the synaptic plasticity of the nanofiber transistor can be synergistically modulated by light pulse and electrical pulse.At last, pulsed light learning and pulsed electrical forgetting behaviors were emulated in 5×5 nanofiber device array.Our results provide new insights into the development of nanofiber optoelectronic neuromorphic devices with synergistic synaptic plasticity.
基金supported by the National Key R&D Program of China(Grant No.2023YFB2503900)the National Natural Science Foundation of China(Grant No.52372203)+1 种基金the National Natural Science Foundation of China(Grant No.52202259)the Shandong Province Natural Science Foundation(ZR2022QE093).
文摘High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance.Herein,the thin layer of two-dimensional(2D)graphitic carbon-nitride(g-C_(3)N_(4))is uniformly coated on the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(denoted as NCM811@CN)using a facile chemical vaporization-assisted synthesis method.As an ideal protective layer,the g-C_(3)N_(4)layer effectively avoids direct contact between the NCM811 cathode and the electrolyte,preventing harmful side reactions and inhibiting secondary crystal cracking.Moreover,the unique nanopore structure and abundant nitrogen vacancy edges in g-C_(3)N_(4)facilitate the adsorption and diffusion of lithium ions,which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode.As a result,the NCM811@CN-3wt%cathode exhibits 161.3 mAh g^(−1)and capacity retention of 84.6%at 0.5 C and 55°C after 400 cycles and 95.7 mAh g^(−1)at 10 C,which is greatly superior to the uncoated NCM811(i.e.129.3 mAh g^(−1)and capacity retention of 67.4%at 0.5 C and 55°C after 220 cycles and 28.8 mAh g^(−1)at 10 C).The improved cycle performance of the NCM811@CN-3wt%cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:LLZTO electrolyte membranes,which show 163.8 mAh g^(−1)and the capacity retention of 88.1%at 0.1 C and 30°C after 200 cycles and 95.3 mAh g^(−1)at 1 C.
基金the National Natural Science Foundation of China (No. 91634108, 21376148 and 61503246)National Key Program(2017FYA0205300)
文摘N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers have been successfully synthesized according to a facile solvothermal/hydrothermal method. The obtained CNTs@α-Fe_2O_3@C nanofibers composites exhibited spe- cial three-dimensional （3-D） network structure, which endows they promising candidate for anode ma- terials of lithium ion battery. The coaxial property of CNTs@α-Fe_2O_3@C nanofibers could significantly improve the cycling and rate performance owing to the acceleration of charge/electron transfer, improve- ment of conductivity, maintaining of structural integrity and inhibiting the aggregation. The α-Fe_2O_3 nanoparticles with small size and high percentage of N-doped amount could further improve the elec- trochemical performance. As for the CNTs@α-Fe_2O_3@C nanofibers, the capacity presented a high value of 1255.4 mAh/g at 0.1 C, and retained at 1213.4 mAh/g after 60 cycles. Even at high rate of 5 C, the ca- pacity still exhibited as high as 319 mAh/g. The results indicated that the synthesized N-doped coaxial CNTs@α-Fe_2O_3@C nanofibers exhibited high cvcling and rate oerformance.
文摘Stable and high‐efficiency bifunctional catalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desired for the practical application of Li‐O_(2)batteries with excellent rate performance and cycle stability.Herein,a novel hybrid bifunctional catalyst with carbon nanofibers inlaid with hollow Co_(3)O_(4)nanoparticles and separate active sites for ORR and OER were prepared and applied in Li‐O_(2)batteries.Benefiting from the synergistic effect of unique porous structural features and high electrocatalytic activity of hollow Co3O4 intimately bound to N‐doped carbon nanofibers,the assembled Li‐O_(2)batteries with novel catalyst exhibited high specific capacity,excellent rate capability,and cycle stability up to 150 cycles under a capacity limitation of 500 mAh g^(–1)at a current density of 100 mA g^(–1).The facile synthesis and preliminary results in this work show the as‐prepared catalyst as a promising bifunctional electrocatalyst for applications in metal‐air batteries,fuel cells,and electrocatalysis.
文摘SnO_(2)/Co_(3)O_(4)nanofibers(NFs)are synthesized by using a homopolar electrospinning system with double jets of positive polarity electric fields.The morphology and structure of SnO_(2)/Co_(3)O_(4)hetero-nanofibers are characterized by using field emission scanning electron microscope(FE-SEM),transmission electron microscope(TEM),x-ray diffraction(XRD),and x-ray photoelectron spectrometer(XPS).The analyses of SnO_(2)/Co_(3)O_(4)NFs by EDS and HRTEM show that the cobalt and tin exist on one nanofiber,which is related to the homopolar electrospinning and the crystallization during sintering.As a typical n-type semiconductor,Sn O_(2)has the disadvantages of high optimal operating temperature and poor reproducibility.Comparing with Sn O_(2),the optimal operating temperature of SnO_(2)/Co_(3)O_(4)NFs is reduced from 350℃to 250℃,which may be related to the catalysis of Co_(2)O_(2).The response of SnO_(2)/Co_(3)O_(4)to 100-ppm ethanol at 250℃is 50.9,9 times higher than that of pure Sn O_(2),which may be attributed to the p–n heterojunction between the n-type Sn O_(2)crystalline grain and the p-type Co_(2)O_(2)crystalline grain.The nanoscale p–n heterojunction promotes the electron migration and forms an interface barrier.The synergy effects between Sn O_(2)and Co_(2)O_(2),the crystalline grain p–n heterojunction,the existence of nanofibers and the large specific surface area all jointly contribute to the improved gas sensing performance.
基金Supported by the Natural Science Foundation of Jilin Province(No.2 0 0 2 0 6 13)
文摘A thin PVA/FeCl_3 composite fiber was prepared by using sol-gel processing and electrospinning techniques. A nanofiber of α-Fe_2O_3 with the diameter of 50_150 nm was obtained via high temperature calcination of the PVA/FeCl_3 composite fiber. The material was characterized by infra-red(IR) spectroscopy, X-ray diffraction(XRD), and scanning electron microscopy(SEM). The results show that the fiber after the calcination at 700 ℃ was a pure α-Fe_2O_3 nanofiber.
基金the National Natural Science Foundation of China (NSFC 20503015)
文摘Supported γ-Al2O3 membranes without defects were prepared by the sol-gel procedure. The sol-gel method involved peptization of a boehmite (AlOOH) sol prepared from ammonium aluminium sulphate. The morphology of the supported membranes was characterized by scanning electron microscopy (SEM) and 3D rotational microscopy. Furthermore, the effects of different preparing conditions on morphological characteristics of the membrane were also investigated. The results show that PVA is a good crack-preventing agent and the morphology of supported membranes is affected by many factors, such as Al2O3 and PVA contents of the sol, drying and sintering procedures and intrinsic defects on the substrate surface.
基金financially supported by the National Natural Science Foundation of China (Nos.51404103,51574117 and 61376073)Hunan Provincial Education Department(No.20C0613)the College Student Innovation and Entrepreneurship Training Program of Hunan Province (No.S2022115350874)。
文摘Considering the intrinsic advantages of natural copiousness and cost-effectiveness of potassium resource,potassium-ion batteries(KIBs) are booming as prospective alternatives to lithium-ion batteries(LIBs) in large-scale energy storage scenarios. Nevertheless, lacking desirable electrodes for reversibly hosting the bulky K+hinders the widespread application of KIBs, and it needs to be urgently solved. Hereon, the porous S-doped Sb_(2)O_(3)-graphene-carbon(SAGC) nanofibers are manufactured through an adjustable and facile approach, which involves electrospinning, in situ etching and sulfuration. The synthesized SAGC is featured by the ultra-small amorphous Sb_(2)O_(3) homogeneously wrapped inside the carbon matrix, as well as the co-incorporation of graphene and sulfur. Tentatively,the SAGC nanofiber sheets are applied as binder-free anodes for KIBs, exhibiting a prominent cycling life(256.72 m Ah·g^(-1) over 150 cycles at 100 m A·g^(-1)) and rate·g^(-1) over 100 cycles at 1 A·g^(-1)). The positive synergy among all the active components accounts for the distinguished performances of the SAGC. By reinforcing the tolerability to the swelling stress, producing the valid electrochemical active sites, and promoting the charge transferring for reversible K+uptake, the SAGC finally renders the excellent cyclability, capacity, and rate capability. Moreover, the extrinsic electrochemical pseudocapacitance characteristics induced by the porous carbon substrate elevate the K-storage capacity of the SAGC as well. It is hoped that the conclusions drawn may offer new insights into a direction for the high-performance binderfree KIB anodes.
