Onedimensional porous carbons bearing high surface areas and sufficient heteroatom doped functionalities are essential for advanced electrochemical energy storage devices,especially for developing freestanding film el...Onedimensional porous carbons bearing high surface areas and sufficient heteroatom doped functionalities are essential for advanced electrochemical energy storage devices,especially for developing freestanding film electrodes.Here we develop a porous,nitrogenenriched,freestanding hollow carbon nanofiber(PNFHCF)electrode material via filtration of polypyrrole(PPy)hollow nanofibers formed by in situ selfdegraded templateassisted strategy,followed by NH3assisted carbonization.The PNFHCF retains the freestanding film morphology that is composed of threedimensional networks from the entanglement of 1D nanofiber and delivers 3.7fold increase in specific surface area(592 m^(2)g^(-1))compared to the carbon without NH_(3)treatment(FHCF).In spite of the enhanced specific surface area,PNFHCF still exhibits comparable high content of surface N functionalities(8.8%,atom fraction)to FHCF.Such developed hierarchical porous structure without sacrificing N doping functionalities together enables the achievement of high capacity,highrate property and good cycling stability when applied as selfsupporting anode in lithiumion batteries,superior to those of FHCF without NH3 treatment.展开更多
MoSe_(2),with high theoretical specific capacity,has attracted a lot of attention.There remains an open challenge to effectively suppress the irreversible selenium dissolution and rapid capacity decrease induced by se...MoSe_(2),with high theoretical specific capacity,has attracted a lot of attention.There remains an open challenge to effectively suppress the irreversible selenium dissolution and rapid capacity decrease induced by severe volume change during cycling.Herein,we synthesize MoSe_(2)nanoflowers dispersed on one-dimensional(1D)N-doped carbon nanofibers(MoSe_(2)@NCNFs)for use as a freestanding electrode.In this unique structure,the 1D N-doped carbon nanofibers are found to not only enhance the conductivity but also ensure the structural integrity during the Li^(+)/Na^(+)insertion/destraction processes.As expected,at 2 A·g^(-1),the specific capacity of the MoSe_(2)@NCNFs is maintained at 180 mAh·g^(-1)after 500 cycles when used in lithium storage applications.Furthermore,in the case of sodium storage,at 1 A·g^(-1),the MoSe_(2)@NCNFs shows a capacity of 122mAh·g^(-1)after 500 cycles.These findings suggest that the MoSe_(2)@NCNF electrodes may be a promising candidate for use in reversible Li/Na storage applications.展开更多
Developing high power and energy supercapacitors(SCs)is a long-pursued goal for the application in transportation and energy storage station.Herein,a rationally-designed Co-doped nickel oxide nanosheets@carbon-welded ...Developing high power and energy supercapacitors(SCs)is a long-pursued goal for the application in transportation and energy storage station.Herein,a rationally-designed Co-doped nickel oxide nanosheets@carbon-welded carbon nanotube foam(Co-doped NiO@WCNTF)as freestanding electrode is successfully prepared for high power and energy SCs.The WCNTF framework with high specific surface area provides three dimensional highly conductive network for fast charge transport and ensures high loading of active materials(9.2 mg/cm2).Moreover,porous Co-doped NiO nanosheets uniformly anchored on the WCNTF framework enable rapid charge kinetics due to the high intrinsic conductivity of Co-doped Ni O nanosheets and their good contact with conductive WCNTF substrate.As a result,the unique integrated electrode with 3D architecture exhibits an ultrahigh specific capacitance of 11.45 F/cm2 at 5 mA/cm2,outstanding rate capability(11.45 F/cm2 at 5 mA/cm2 and a capacitance retention of 86.2%at 30 mA/cm2)and good cycling stability,suggesting great potential for high performance supercapacitor.展开更多
Sb-based materials with high specific capacity have targeted as an alternative anode material for alkali metal ion batteries.Herein,Sb nanoparticles embedded in hollow porous N-doped carbon nanotubes(Sb@N-C nanotubes)...Sb-based materials with high specific capacity have targeted as an alternative anode material for alkali metal ion batteries.Herein,Sb nanoparticles embedded in hollow porous N-doped carbon nanotubes(Sb@N-C nanotubes)are used as freestanding anode for Li-ion batteries(LIBs)and K-ion batteries(PIBs).The Sb@N-C nanotubes demonstrate exceptional reversible capacity of643 mAh·g^(-1)at 0.1 A·g^(-1)with long cycle stability,as well as outstanding rate performance(219.6 mAh·g^(-1)at10 A·g^(-1))in LIBs.As the anode material of PIBs,they reveal impressive capacity of 325.4 mAh·g^(-1)at 0.1 A·g^(-1).The superior electrochemical properties mainly originate from the novel structure.To be specific,the obtained 3D connected network allows for quick ion and electron migration,and prevents the aggregation of Sb nanoparticles.The hollow porous nanotubes can not only accommodate the volume expansion of Sb nanoparticles during cycling,but also facilitate the infiltration of the electrolyte and reduce the ion diffusion length.This work provides a new insight for designing advanced Sb-based anodes for alkali metal ion batteries.展开更多
Constructing 3 D multifunctional conductive framework as stable sulfur cathode contributes to develop advanced lithium-sulfur(Li-S)batteries.Herein,a freestanding electrode with nickel foam framework and nitrogen dope...Constructing 3 D multifunctional conductive framework as stable sulfur cathode contributes to develop advanced lithium-sulfur(Li-S)batteries.Herein,a freestanding electrode with nickel foam framework and nitrogen doped porous carbon(PC)network is presented to encapsulate active sulfur for Li-S batteries.In such a mutually embedded architecture with high stability,the interconnected carbon network and nickel foam matrix can expedite ionic/electro nic tra nsport and sustain volume variations of sulfur.Furthermore,rationally designed porous structures provide sufficient internal space and large surface area for high active sulfur loading and polar polysulfides anchoring.Benefiting from the synergistic superiority,the Ni/PC-S cathode exhibits a high initial capacity of around 1200 mAh/g at 0.2 C,excelle nt rate perfo rmance,and high cycling stability with a low decay rate of 0.059%per cycle after 500 cycles.This work provides a useful strategy to exploit freestanding porous framework for diverse applications.展开更多
Transitional metal selenides have high conductivity,even metal quality,which makes them great for using as electrode materials for fabricating supercapacitors.Here,hierarchical Ni_(3)Se_(2)nanosheet-on-nanorods on Ni ...Transitional metal selenides have high conductivity,even metal quality,which makes them great for using as electrode materials for fabricating supercapacitors.Here,hierarchical Ni_(3)Se_(2)nanosheet-on-nanorods on Ni foam(NSR-Ni_(3)Se_(2)/Ni)was fabricated by a facile three-dimensional(3D)substrate-assisted confinement assembly method,and used as a freestanding electrode material for hybrid supercapacitors(HSCs).In this design,metallic Ni_(3)Se_(2)with hybrid 1D/2D architecture could effectively enhance the active specific surface area of electrode and improve space utilization,as well as significantly facilitate electrons transport,while Ni foam served as the Ni source of Ni_(3)Se_(2)and provided 3D multi-electron transport channels,thus boosting the specific capacity.The constructed hierarchical NSR-Ni_(3)Se_(2)electrode delivered a superior areal specific capacity of 1.068 mAh/cm^(2)(7.69 F/cm^(2))at 2 mA/cm^(2)and retained 68.2%of the initial capacity when the current density increases by 15 times.Furthermore,the as-assembled NSR-Ni_(3)Se_(2)device exhibited an ultrahigh energy density of 56.4 Wh/kg and high power density of 4640.3 W/kg,and a capacity retention of 92.6%even after 6000 cycles.展开更多
基金the National Natural Science Foundation of China(51972270,51702262,51911530212,51872240,51672225,61805201)the China Postdoctoral Science Foundation(2018T111093,2018M643732,2018BSHYDZZ57)+3 种基金the Natural Science Foundation of Shaanxi Province(2020JZ-07)the Key Research and Development Program of Shaanxi Province(2019TSLGY07-03)the Fundamental Research Funds for the Central Universities(3102019JC005 and 3102019ghxm004)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(2019-QZ-03).
文摘Onedimensional porous carbons bearing high surface areas and sufficient heteroatom doped functionalities are essential for advanced electrochemical energy storage devices,especially for developing freestanding film electrodes.Here we develop a porous,nitrogenenriched,freestanding hollow carbon nanofiber(PNFHCF)electrode material via filtration of polypyrrole(PPy)hollow nanofibers formed by in situ selfdegraded templateassisted strategy,followed by NH3assisted carbonization.The PNFHCF retains the freestanding film morphology that is composed of threedimensional networks from the entanglement of 1D nanofiber and delivers 3.7fold increase in specific surface area(592 m^(2)g^(-1))compared to the carbon without NH_(3)treatment(FHCF).In spite of the enhanced specific surface area,PNFHCF still exhibits comparable high content of surface N functionalities(8.8%,atom fraction)to FHCF.Such developed hierarchical porous structure without sacrificing N doping functionalities together enables the achievement of high capacity,highrate property and good cycling stability when applied as selfsupporting anode in lithiumion batteries,superior to those of FHCF without NH3 treatment.
基金supported by the National Natural Science Foundation of China (No.52102296)the Guangzhou Municipal Science and Technology Bureau (No.202102020055)+2 种基金the Science and Technology Program of Guangzhou (No.2019050001)the Outstanding Youth Project of Guangdong Natural Science Foundation (No.2021B1515020051)the Yunnan Expert Workstation (No.202005AF150028)。
文摘MoSe_(2),with high theoretical specific capacity,has attracted a lot of attention.There remains an open challenge to effectively suppress the irreversible selenium dissolution and rapid capacity decrease induced by severe volume change during cycling.Herein,we synthesize MoSe_(2)nanoflowers dispersed on one-dimensional(1D)N-doped carbon nanofibers(MoSe_(2)@NCNFs)for use as a freestanding electrode.In this unique structure,the 1D N-doped carbon nanofibers are found to not only enhance the conductivity but also ensure the structural integrity during the Li^(+)/Na^(+)insertion/destraction processes.As expected,at 2 A·g^(-1),the specific capacity of the MoSe_(2)@NCNFs is maintained at 180 mAh·g^(-1)after 500 cycles when used in lithium storage applications.Furthermore,in the case of sodium storage,at 1 A·g^(-1),the MoSe_(2)@NCNFs shows a capacity of 122mAh·g^(-1)after 500 cycles.These findings suggest that the MoSe_(2)@NCNF electrodes may be a promising candidate for use in reversible Li/Na storage applications.
基金the National Natural Science Foundation of China(U1710122,51862035 and 21773293)the Science and Technology Project of Jiangxi Province(20181ACH80008,20181ACE50012,20192BCD40017 and 20192ACB80002)+1 种基金Jiangxi Double Thousand Talent Program(S2018LQCQ0016)Suzhou Science and Technology Plan Projects(SYG201831)。
文摘Developing high power and energy supercapacitors(SCs)is a long-pursued goal for the application in transportation and energy storage station.Herein,a rationally-designed Co-doped nickel oxide nanosheets@carbon-welded carbon nanotube foam(Co-doped NiO@WCNTF)as freestanding electrode is successfully prepared for high power and energy SCs.The WCNTF framework with high specific surface area provides three dimensional highly conductive network for fast charge transport and ensures high loading of active materials(9.2 mg/cm2).Moreover,porous Co-doped NiO nanosheets uniformly anchored on the WCNTF framework enable rapid charge kinetics due to the high intrinsic conductivity of Co-doped Ni O nanosheets and their good contact with conductive WCNTF substrate.As a result,the unique integrated electrode with 3D architecture exhibits an ultrahigh specific capacitance of 11.45 F/cm2 at 5 mA/cm2,outstanding rate capability(11.45 F/cm2 at 5 mA/cm2 and a capacitance retention of 86.2%at 30 mA/cm2)and good cycling stability,suggesting great potential for high performance supercapacitor.
基金financially supported by the National Key Research and Development Program of China(No.2019YFB2205005)the Natural Science Foundation of Fujian Province(No.2020 JO1050)。
文摘Sb-based materials with high specific capacity have targeted as an alternative anode material for alkali metal ion batteries.Herein,Sb nanoparticles embedded in hollow porous N-doped carbon nanotubes(Sb@N-C nanotubes)are used as freestanding anode for Li-ion batteries(LIBs)and K-ion batteries(PIBs).The Sb@N-C nanotubes demonstrate exceptional reversible capacity of643 mAh·g^(-1)at 0.1 A·g^(-1)with long cycle stability,as well as outstanding rate performance(219.6 mAh·g^(-1)at10 A·g^(-1))in LIBs.As the anode material of PIBs,they reveal impressive capacity of 325.4 mAh·g^(-1)at 0.1 A·g^(-1).The superior electrochemical properties mainly originate from the novel structure.To be specific,the obtained 3D connected network allows for quick ion and electron migration,and prevents the aggregation of Sb nanoparticles.The hollow porous nanotubes can not only accommodate the volume expansion of Sb nanoparticles during cycling,but also facilitate the infiltration of the electrolyte and reduce the ion diffusion length.This work provides a new insight for designing advanced Sb-based anodes for alkali metal ion batteries.
基金financially supported by the National Natural Science Foundation of China(No.21603109)the Henan Joint Fund of theNational Natural Science Foundation of China(No.U1404216)。
文摘Constructing 3 D multifunctional conductive framework as stable sulfur cathode contributes to develop advanced lithium-sulfur(Li-S)batteries.Herein,a freestanding electrode with nickel foam framework and nitrogen doped porous carbon(PC)network is presented to encapsulate active sulfur for Li-S batteries.In such a mutually embedded architecture with high stability,the interconnected carbon network and nickel foam matrix can expedite ionic/electro nic tra nsport and sustain volume variations of sulfur.Furthermore,rationally designed porous structures provide sufficient internal space and large surface area for high active sulfur loading and polar polysulfides anchoring.Benefiting from the synergistic superiority,the Ni/PC-S cathode exhibits a high initial capacity of around 1200 mAh/g at 0.2 C,excelle nt rate perfo rmance,and high cycling stability with a low decay rate of 0.059%per cycle after 500 cycles.This work provides a useful strategy to exploit freestanding porous framework for diverse applications.
基金the financial support from the National Key R&D Program of China(Nos.2017YFB1104300 and 2016YFA0200200)National Natural Science Foundation of China(Nos.21575014,21905025,91963113)。
文摘Transitional metal selenides have high conductivity,even metal quality,which makes them great for using as electrode materials for fabricating supercapacitors.Here,hierarchical Ni_(3)Se_(2)nanosheet-on-nanorods on Ni foam(NSR-Ni_(3)Se_(2)/Ni)was fabricated by a facile three-dimensional(3D)substrate-assisted confinement assembly method,and used as a freestanding electrode material for hybrid supercapacitors(HSCs).In this design,metallic Ni_(3)Se_(2)with hybrid 1D/2D architecture could effectively enhance the active specific surface area of electrode and improve space utilization,as well as significantly facilitate electrons transport,while Ni foam served as the Ni source of Ni_(3)Se_(2)and provided 3D multi-electron transport channels,thus boosting the specific capacity.The constructed hierarchical NSR-Ni_(3)Se_(2)electrode delivered a superior areal specific capacity of 1.068 mAh/cm^(2)(7.69 F/cm^(2))at 2 mA/cm^(2)and retained 68.2%of the initial capacity when the current density increases by 15 times.Furthermore,the as-assembled NSR-Ni_(3)Se_(2)device exhibited an ultrahigh energy density of 56.4 Wh/kg and high power density of 4640.3 W/kg,and a capacity retention of 92.6%even after 6000 cycles.