To promote the energy density of symmetric all-solid-state supercapacitors(SCs),efforts have been dedicated to searching for high-performance electrode materials recently. In this paper,vanadium nitride(VN) nanofibers...To promote the energy density of symmetric all-solid-state supercapacitors(SCs),efforts have been dedicated to searching for high-performance electrode materials recently. In this paper,vanadium nitride(VN) nanofibers with mesoporous structure have been fabricated by a facile electrospinning method. Their crystal structures and morphology features were characterized by X-ray diffraction,scanning electron microscopy,and transmission electron microscopy. The mesoporous structure of VN nanofibers,which can provide short electrolyte diffusion routes and conducting electron transport pathways,is beneficial to their performance as a supercapacitor electrode. Under a stable electrochemical window of 1.0 V,VN nanofibers possess an excellent mass specific capacitance of 110.8 F/g at a scan rate of 5 mV/s. Moreover,the VN nanofibers were further assembled into symmetric all-solid-state SCs,achieving a high energy density of 0.89 mW·h/cm^3 and a high power density of 0.016 W/cm^3 over an operating potential range from 0 to 1.0 V. These results demonstrate that VN nanofibers could be potentially used for energy storage devices.展开更多
Hydrogen isotope permeation through structural materials is a key issue for developing nuclear fusion energy,which will cause fuel loss and radioactive pollution.Developing ceramic coatings with high thermal shock and...Hydrogen isotope permeation through structural materials is a key issue for developing nuclear fusion energy,which will cause fuel loss and radioactive pollution.Developing ceramic coatings with high thermal shock and hydrogen resistance is an effective strategy to solve this issue.In this work,a layer-structured Cr/Cr_(x)N coating was successfully fabricated by a facile electroplatingbased nitridation technique,which is easy,facile,and applicable to coating complex-shaped substrates.The Cr/Cr_(x)N coating,composed of a bottom Fe/Cr interdiffusion zone,a middle Cr layer,and a top Cr_(x)N layer,exhibits high bonding strength,high anti-thermal-shock ability,and high deuterium permeation resistance.Its bonding strength achieves 43.6 MPa.The Cr/Cr_(x)N coating remains intact even after suffering 300 thermal shock cycles under a 600℃–water condition.Through optimizing the nitridation temperature,the Cr/Cr_(x)N coating achieves a deuterium permeation reduction factor(PRF)as high as 3599 at 500℃.Considering its scalable fabrication technique and considerable properties,the developed Cr/Cr_(x)N coating may serve as a novel high-performance hydrogen permeation barrier in various fields.展开更多
Ultrafine silver fiber is an alternative to commercial indium tin oxide(ITO) as a new-generation flexible transparent conductor that can be used in flexible electronics.However,its primary limitation is the unrepeatab...Ultrafine silver fiber is an alternative to commercial indium tin oxide(ITO) as a new-generation flexible transparent conductor that can be used in flexible electronics.However,its primary limitation is the unrepeatable optoelectronic properties due to the disordered distribution of silver fibers.In this work,we report the in-situ direct writing of the silver microfiber pattern with high conductivity and transparency to attain a flexible transparent conductor.The silver network is composed of silver microfibers,which can be artificially designed and regularly patterned under the precise control of the fiber position and shape;this is crucial for regulating its optoelectronic properties.Herein,a high-performance conductor is achieved in the silver network with high stability.This novel conductor has a sheet resistance of 2 Ω sq-1at 90% transparency,which corre sponds to a high Figure of merit σdc/σopt=1742.The in-situ direct writing technique developed here is distinct from other fabrication methods because it requires no transfer steps,templates or heating.Further,this silver network is integrated into a light-printable rewritable device,and can be used as a wearable heater;this heater when driven by a 1.5 V battery attains a temperature of up to 55.6℃.Therefore,in-situ direct writing is expected to offer a new platform for facile,scalable,and ultralow-cost production of high-performance metal networks for flexible transparent conductors.展开更多
基金supported by the Young Elite Scientists Sponsorship Program by CAST (Grant No. 2017QNRC001)the National Natural Science Foundation of China (Grant No. 51402116)
文摘To promote the energy density of symmetric all-solid-state supercapacitors(SCs),efforts have been dedicated to searching for high-performance electrode materials recently. In this paper,vanadium nitride(VN) nanofibers with mesoporous structure have been fabricated by a facile electrospinning method. Their crystal structures and morphology features were characterized by X-ray diffraction,scanning electron microscopy,and transmission electron microscopy. The mesoporous structure of VN nanofibers,which can provide short electrolyte diffusion routes and conducting electron transport pathways,is beneficial to their performance as a supercapacitor electrode. Under a stable electrochemical window of 1.0 V,VN nanofibers possess an excellent mass specific capacitance of 110.8 F/g at a scan rate of 5 mV/s. Moreover,the VN nanofibers were further assembled into symmetric all-solid-state SCs,achieving a high energy density of 0.89 mW·h/cm^3 and a high power density of 0.016 W/cm^3 over an operating potential range from 0 to 1.0 V. These results demonstrate that VN nanofibers could be potentially used for energy storage devices.
基金supported by the National MCF Energy R&D Program(Grant No.2018YFE0313300)the National Natural Science Foundation of China(Grant No.51402116)the Fundamental Research Funds for the Central Universities(Grant Nos.2018KFYYXJJ028 and 2019KFYXMBZ045).
文摘Hydrogen isotope permeation through structural materials is a key issue for developing nuclear fusion energy,which will cause fuel loss and radioactive pollution.Developing ceramic coatings with high thermal shock and hydrogen resistance is an effective strategy to solve this issue.In this work,a layer-structured Cr/Cr_(x)N coating was successfully fabricated by a facile electroplatingbased nitridation technique,which is easy,facile,and applicable to coating complex-shaped substrates.The Cr/Cr_(x)N coating,composed of a bottom Fe/Cr interdiffusion zone,a middle Cr layer,and a top Cr_(x)N layer,exhibits high bonding strength,high anti-thermal-shock ability,and high deuterium permeation resistance.Its bonding strength achieves 43.6 MPa.The Cr/Cr_(x)N coating remains intact even after suffering 300 thermal shock cycles under a 600℃–water condition.Through optimizing the nitridation temperature,the Cr/Cr_(x)N coating achieves a deuterium permeation reduction factor(PRF)as high as 3599 at 500℃.Considering its scalable fabrication technique and considerable properties,the developed Cr/Cr_(x)N coating may serve as a novel high-performance hydrogen permeation barrier in various fields.
基金supported by National MCF Energy R&D Program(No.2018YFE0313300)Young Elite Scientists Sponsorship Program by CAST(No.2017QNRC001)+2 种基金the National Natural Science Foundation of China(No.51402116)the Fundamental Research Funds for the Central Universities(Nos.2018KFYYXJJ028and 2019KFYXMBZ045)the Analytical and Testing Center of Huazhong University of Science and Technology for support。
文摘Ultrafine silver fiber is an alternative to commercial indium tin oxide(ITO) as a new-generation flexible transparent conductor that can be used in flexible electronics.However,its primary limitation is the unrepeatable optoelectronic properties due to the disordered distribution of silver fibers.In this work,we report the in-situ direct writing of the silver microfiber pattern with high conductivity and transparency to attain a flexible transparent conductor.The silver network is composed of silver microfibers,which can be artificially designed and regularly patterned under the precise control of the fiber position and shape;this is crucial for regulating its optoelectronic properties.Herein,a high-performance conductor is achieved in the silver network with high stability.This novel conductor has a sheet resistance of 2 Ω sq-1at 90% transparency,which corre sponds to a high Figure of merit σdc/σopt=1742.The in-situ direct writing technique developed here is distinct from other fabrication methods because it requires no transfer steps,templates or heating.Further,this silver network is integrated into a light-printable rewritable device,and can be used as a wearable heater;this heater when driven by a 1.5 V battery attains a temperature of up to 55.6℃.Therefore,in-situ direct writing is expected to offer a new platform for facile,scalable,and ultralow-cost production of high-performance metal networks for flexible transparent conductors.