In this work, nickel nanopore arrays with a highly-oriented nanoporous structure inherited from por- ous alumina membranes were used as nanostructured current collectors for constructing ultrahigh rate solid-state sup...In this work, nickel nanopore arrays with a highly-oriented nanoporous structure inherited from por- ous alumina membranes were used as nanostructured current collectors for constructing ultrahigh rate solid-state supercapacitors. A thin layer of poly（3,4-ethylenediox- ythiophene） （PEDOT） as electroactive materials was conformally coated onto nickel nanopores to form heterostructured electrodes. The as-prepared electrodes have a large specific surface area to ensure a high capacity, and the highly-oriented nanoporous structure of nickel nanopores reduces the ion transport resistance, allowing the ions in the solid-state electrolytes to quickly access the PEDOT surface during the fast charge-discharge process. As a result, the assembled solid-state supercapacitor in a symmetric configuration exhibits an ideal capacitive behavior and a superior rate capability even at an ultrahigh scan rate of 50 V· s^-1.展开更多
An effective method is designed to construct three-dimensional(3D)Nb_(2)C/reduced graphene oxide(rGO)hybrid aerogels through a low-temperature graphene oxide(GO)-assisted hydrothermal self-assembly followed by freeze-...An effective method is designed to construct three-dimensional(3D)Nb_(2)C/reduced graphene oxide(rGO)hybrid aerogels through a low-temperature graphene oxide(GO)-assisted hydrothermal self-assembly followed by freeze-drying and annealing.The intimately coupled Nb_(2)C/rGO hybrid aerogel combines the advantages of large specific surface area and rich 3D interconnected porous structure of aerogel as well as high conductivity and low potassium diffusion energy barrier of Nb_(2)C,which not only effectively prevents the self-restacking of Nb2C nanosheets to allow more active sites exposed and accommodate the volume change during the charge/discharge process,but also increases the accessibility of electrolyte and promotes the rapid transfer of ions/electrons.As a result,Nb_(2)C/rGO-2 as the anode of potassium ion batteries(KIBs)delivers a large reversible specific capacity(301.7 mAh·g^(−1)after 500 cycles at 2.0 A·g^(−1)),an ultrahigh rate capability(155.5 mAh·g^(−1)at 20 A·g^(−1)),and an excellent long-term large-current cycle stability(198.8 mAh·g^(−1)after 1,000 cycles at 10 A·g^(−1),with a retention of 83.3%).Such a high-level electrochemical performance,especially the ultrahigh rate capability,is the best among transition metal carbides and nitride(MXene)-based materials reported so far for KIBs.The diffusion kinetics of K+is investigated thoroughly,and the synergetic charge–discharge mechanism and the structure–performance relationship of Nb_(2)C/rGO are revealed explicitly.The present work provides a good strategy to solve the self-restacking problem of two-dimensional materials and also enlarges the potential applications of MXenes.展开更多
MXene is a promising energy storage material for miniaturized microbatteries and microsupercapacitors(MSCs).Despite its superior electrochemical performance,only a few studies have reported MXene-based ultrahigh-rate(...MXene is a promising energy storage material for miniaturized microbatteries and microsupercapacitors(MSCs).Despite its superior electrochemical performance,only a few studies have reported MXene-based ultrahigh-rate(>1000 mV s^(−1))on-paper MSCs,mainly due to the reduced electrical conductance of MXene films deposited on paper.Herein,ultrahigh-rate metal-free on-paper MSCs based on heterogeneous MXene/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT:PSS)-stack electrodes are fabricated through the combination of direct ink writing and femtosecond laser scribing.With a footprint area of only 20 mm^(2),the on-paper MSCs exhibit excellent high-rate capacitive behavior with an areal capacitance of 5.7 mF cm^(−2)and long cycle life(>95%capacitance retention after 10,000 cycles)at a high scan rate of 1000 mV s^(−1),outperforming most of the present on-paper MSCs.Furthermore,the heterogeneous MXene/PEDOT:PSS electrodes can interconnect individual MSCs into metal-free on-paper MSC arrays,which can also be simultaneously charged/discharged at 1000 mV s^(−1),showing scalable capacitive performance.The heterogeneous MXene/PEDOT:PSS stacks are a promising electrode structure for on-paper MSCs to serve as ultrafast miniaturized energy storage components for emerging paper electronics.展开更多
针对评估射频识别技术RFID(Radio Frequency Identification)系统性能目标区域识别率的影响因素展开研究,从典型无源超高频RFID系统传播模型出发,讨论分析了影响识别率的主要因素,提出了多标签法和干扰抵消法两种识别率的优化方法。并...针对评估射频识别技术RFID(Radio Frequency Identification)系统性能目标区域识别率的影响因素展开研究,从典型无源超高频RFID系统传播模型出发,讨论分析了影响识别率的主要因素,提出了多标签法和干扰抵消法两种识别率的优化方法。并就两种方法分别进行了实验测试,测试结果表明,采用两种方法目标区域识别率能分别提高11%和7.86%,能有效改善无源超高频RFID系统性能。展开更多
Red phosphorus(RP)is beneficial to industrialization due to its rich resources,chemical stability and environmental friendliness.However,the low electronic conductivity and large volume expansion limit its application...Red phosphorus(RP)is beneficial to industrialization due to its rich resources,chemical stability and environmental friendliness.However,the low electronic conductivity and large volume expansion limit its application for energy storage.Herein,we first used RP to prepare a novel bouquet-like Co_(3)(HPO_(4))_(2)(OH)_(2) by the hydrothermal approach as cathode materials for hybrid supercapacitors(HSC),which delivered a large specific capacity(119.2 mA h g^(−1) at 1 A g^(−1)),a superb rate capability(83.6 mA h g^(−1) at 100 A g^(−1))and a splendid electrochemical stability(92%capacity retention after 5000 cycles at 10 A g^(−1)).Furthermore,a novel HSC device assembled with Co_(3)(HPO_(4))_(2)(OH)_(2) as the cathode,porous carbon(PC)as the anode showed a high energy density of 44.6 W h kg^(−1) and a remarkable power density of 33.75 kW kg^(−1),along with an exceptional cyclic performance(91.8%capacity retention after 10,000 cycles at 3 A g^(−1)).This study not only develops a novel type of high-performance battery-type cathode material,but also provides a new idea for the industrial application of RP.展开更多
文摘In this work, nickel nanopore arrays with a highly-oriented nanoporous structure inherited from por- ous alumina membranes were used as nanostructured current collectors for constructing ultrahigh rate solid-state supercapacitors. A thin layer of poly（3,4-ethylenediox- ythiophene） （PEDOT） as electroactive materials was conformally coated onto nickel nanopores to form heterostructured electrodes. The as-prepared electrodes have a large specific surface area to ensure a high capacity, and the highly-oriented nanoporous structure of nickel nanopores reduces the ion transport resistance, allowing the ions in the solid-state electrolytes to quickly access the PEDOT surface during the fast charge-discharge process. As a result, the assembled solid-state supercapacitor in a symmetric configuration exhibits an ideal capacitive behavior and a superior rate capability even at an ultrahigh scan rate of 50 V· s^-1.
基金the National Natural Science Foundation of China(No.21773116)and Modern Analysis Center of Nanjing University.
文摘An effective method is designed to construct three-dimensional(3D)Nb_(2)C/reduced graphene oxide(rGO)hybrid aerogels through a low-temperature graphene oxide(GO)-assisted hydrothermal self-assembly followed by freeze-drying and annealing.The intimately coupled Nb_(2)C/rGO hybrid aerogel combines the advantages of large specific surface area and rich 3D interconnected porous structure of aerogel as well as high conductivity and low potassium diffusion energy barrier of Nb_(2)C,which not only effectively prevents the self-restacking of Nb2C nanosheets to allow more active sites exposed and accommodate the volume change during the charge/discharge process,but also increases the accessibility of electrolyte and promotes the rapid transfer of ions/electrons.As a result,Nb_(2)C/rGO-2 as the anode of potassium ion batteries(KIBs)delivers a large reversible specific capacity(301.7 mAh·g^(−1)after 500 cycles at 2.0 A·g^(−1)),an ultrahigh rate capability(155.5 mAh·g^(−1)at 20 A·g^(−1)),and an excellent long-term large-current cycle stability(198.8 mAh·g^(−1)after 1,000 cycles at 10 A·g^(−1),with a retention of 83.3%).Such a high-level electrochemical performance,especially the ultrahigh rate capability,is the best among transition metal carbides and nitride(MXene)-based materials reported so far for KIBs.The diffusion kinetics of K+is investigated thoroughly,and the synergetic charge–discharge mechanism and the structure–performance relationship of Nb_(2)C/rGO are revealed explicitly.The present work provides a good strategy to solve the self-restacking problem of two-dimensional materials and also enlarges the potential applications of MXenes.
基金China Scholarship Council,Grant/Award Number:201906230359Vetenskapsrådet,Grant/Award Number:2019-04731+4 种基金HORIZON EUROPE Digital,Industry and Space,Grant/Award Number:101070255Stiftelsen Olle Engkvist Byggmästare,Grant/Award Number:2014/799Swedish National Infrastructure in Advanced Electron Microscopy,Grant/Award Numbers:2021-00171,RIF21-0026KTH Energy Platform,Grant/Award Number:HT2021Swedish Foundation for Strategic Research,Grant/Award Number:STP19-0014。
文摘MXene is a promising energy storage material for miniaturized microbatteries and microsupercapacitors(MSCs).Despite its superior electrochemical performance,only a few studies have reported MXene-based ultrahigh-rate(>1000 mV s^(−1))on-paper MSCs,mainly due to the reduced electrical conductance of MXene films deposited on paper.Herein,ultrahigh-rate metal-free on-paper MSCs based on heterogeneous MXene/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT:PSS)-stack electrodes are fabricated through the combination of direct ink writing and femtosecond laser scribing.With a footprint area of only 20 mm^(2),the on-paper MSCs exhibit excellent high-rate capacitive behavior with an areal capacitance of 5.7 mF cm^(−2)and long cycle life(>95%capacitance retention after 10,000 cycles)at a high scan rate of 1000 mV s^(−1),outperforming most of the present on-paper MSCs.Furthermore,the heterogeneous MXene/PEDOT:PSS electrodes can interconnect individual MSCs into metal-free on-paper MSC arrays,which can also be simultaneously charged/discharged at 1000 mV s^(−1),showing scalable capacitive performance.The heterogeneous MXene/PEDOT:PSS stacks are a promising electrode structure for on-paper MSCs to serve as ultrafast miniaturized energy storage components for emerging paper electronics.
文摘针对评估射频识别技术RFID(Radio Frequency Identification)系统性能目标区域识别率的影响因素展开研究,从典型无源超高频RFID系统传播模型出发,讨论分析了影响识别率的主要因素,提出了多标签法和干扰抵消法两种识别率的优化方法。并就两种方法分别进行了实验测试,测试结果表明,采用两种方法目标区域识别率能分别提高11%和7.86%,能有效改善无源超高频RFID系统性能。
基金financially supported by the National Natural Science Foundation of China(21601057)Hunan Provincial Natural Science Foundation(2021JJ30216)。
文摘Red phosphorus(RP)is beneficial to industrialization due to its rich resources,chemical stability and environmental friendliness.However,the low electronic conductivity and large volume expansion limit its application for energy storage.Herein,we first used RP to prepare a novel bouquet-like Co_(3)(HPO_(4))_(2)(OH)_(2) by the hydrothermal approach as cathode materials for hybrid supercapacitors(HSC),which delivered a large specific capacity(119.2 mA h g^(−1) at 1 A g^(−1)),a superb rate capability(83.6 mA h g^(−1) at 100 A g^(−1))and a splendid electrochemical stability(92%capacity retention after 5000 cycles at 10 A g^(−1)).Furthermore,a novel HSC device assembled with Co_(3)(HPO_(4))_(2)(OH)_(2) as the cathode,porous carbon(PC)as the anode showed a high energy density of 44.6 W h kg^(−1) and a remarkable power density of 33.75 kW kg^(−1),along with an exceptional cyclic performance(91.8%capacity retention after 10,000 cycles at 3 A g^(−1)).This study not only develops a novel type of high-performance battery-type cathode material,but also provides a new idea for the industrial application of RP.
