Zeolitic-imidazole frameworks(ZIFs)derivations have widely emerged as an efficient air cathode of zinc-air batteries(ZABs)due to excellent bifunctional oxygen electrocatalysis performance.However,they are not stable e...Zeolitic-imidazole frameworks(ZIFs)derivations have widely emerged as an efficient air cathode of zinc-air batteries(ZABs)due to excellent bifunctional oxygen electrocatalysis performance.However,they are not stable enough for long-term operation of rechargeable ZABs because of weak association with current collector,especially under bending conditions for flexible ZAB devices.Here,we show that by purposely designing coordinatively unsaturated ZIFs via a facile morphology regulation,which can be chemically linked on acid-treated carbon cloth,a stable Co-N-C air cathode is therefore derived where Co nanoparticles(NPs)are uniformly confined within the Co-N-C matrix on carbon cloth(Co/Co-N-C/CC).Specifically,when without being stabilized from carbon cloth,the pyrolysis of ZIFs with different unsaturated coordination levels has a negligible impact on the bifunctional oxygen-catalyzed performance.The optimal Co/Co-N-C/CC catalyst assembled ZAB possesses a large open circuit voltage of 1.415 V and a high peak power density of 163 mW·cm^(−2) as well as excellent cycling durability upon 630 discharge–charge cycles with 61%voltage efficiency remained,largely exceeding those of a benchmark Pt/C-IrO_(2) catalyst assembled ZAB.The synergy between Co NPs and active Co-N-C sites via electronic interaction induces the outstanding bifunctional oxygen-catalyzed activity and cathode performance.The present work highlights the importance of unsaturated coordination structures in ZIFs precursors for the performance of derived nanostructures in integrated electrodes.展开更多
将三聚氰胺和Co的硝酸盐均质化混合后在N2氛围下热处理,使用H_(2)O_(2)对材料刻蚀后制得一种钴掺杂氮碳材料。经过扫描电镜、X射线衍射分析、X射线光电子能谱分析等测试显示材料为一种碳纳米管结构。电化学性能测试显示催化剂氧还原反...将三聚氰胺和Co的硝酸盐均质化混合后在N2氛围下热处理,使用H_(2)O_(2)对材料刻蚀后制得一种钴掺杂氮碳材料。经过扫描电镜、X射线衍射分析、X射线光电子能谱分析等测试显示材料为一种碳纳米管结构。电化学性能测试显示催化剂氧还原反应主要依靠四电子反应。线性扫描伏安测试显示半坡电位为832 mV,但是其功率密度为6.0 m A·cm^(-2),显示出该催化剂的氧还原能力,其抗甲醇能力和稳定性也优于商业化的Pt/C催化剂。展开更多
Lithium-ion batteries(LIBs) are considered new generation of large-scale energy-storage devices.However,LIBs suffer from a lack of desirable anode materials with excellent specific capacity and cycling stability.In th...Lithium-ion batteries(LIBs) are considered new generation of large-scale energy-storage devices.However,LIBs suffer from a lack of desirable anode materials with excellent specific capacity and cycling stability.In this work,we design a novel hierarchical structure constructed by encapsulating cobalt sulfide nanowires within nitrogen-doped porous branched carbon nanotubes(NBNTs)for LIBs.The unique hierarchical Co9S8@NBNT electrode displayed a reversible specific capacity of 1310 mAhg-1 at a current density of 0.1 Ag-1,and was able to maintain a stable reversible discharge capacity of 1109 mAhg-1 at a current density of 0.5 Ag-1 with coulombic efficiency reaching almost 100% for 200 cycles.The excellent rate and cycling capabilities can be ascribed to the hierarchical porosity of the one-dimensional Co9S8@NBNT internetworks,the incorporation of nitrogen doping,and the carbon nanotube confinement of the active cobalt sulfide nanowires offering a proximate electron pathway for the isolated nanoparticles and shielding of the cobalt sulfide nanowires from pulverization over long cycling periods.展开更多
Conversion-type anode materials with a high charge storage capability generally su er from large volume expansion, poor electron conductivity, and sluggish metal ion transport kinetics. The electrode material describe...Conversion-type anode materials with a high charge storage capability generally su er from large volume expansion, poor electron conductivity, and sluggish metal ion transport kinetics. The electrode material described in this paper, namely cobalt sulphide nanoparticles encapsulated in carbon cages(Co9S8@NC), can circumvent these problems. This electrode material exhibited a reversible sodium-ion storage capacity of 705 mAh g^-1 at 100 mA g^-1 with an extraordinary rate capability and good cycling stability. Mechanistic study using the in situ transmission electron microscope technique revealed that the volumetric expansion of the Co9S8 nanoparticles is bu ered by the carbon cages, enabling a stable electrode–electrolyte interface. In addition, the carbon shell with high-content doped nitrogen significantly enhances the electron conductivity of the Co9S8@NC electrode material and provides doping-induced active sites to accommodate sodium ions. By integrating the Co9S8@NC as negative electrode with a cellulose-derived porous hard carbon/graphene oxide composite as positive electrode and 1 M NaPF6 in diglyme as the electrolyte, the sodium-ion capacitor full cell can achieve energy densities of 101.4 and 45.8 Wh kg^-1 at power densities of 200 and 10,000 W kg^-1, respectively.展开更多
Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air...Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets(Co/N-Pg) is fabricated for Zn–air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap(0.81 V at 50 mA cm^-2) and high peak power density(119 mW cm^-2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.展开更多
In this work, nitrogen-doped cobalt nanoparticlesinitrogen-doped plate-like ordered mesoporous carbons (N/Co/OMCs) were used as noble-metal free electrocatalysts with high catalytic efficiency. Compared with OMCs with...In this work, nitrogen-doped cobalt nanoparticlesinitrogen-doped plate-like ordered mesoporous carbons (N/Co/OMCs) were used as noble-metal free electrocatalysts with high catalytic efficiency. Compared with OMCs with long channel length, due to more entrances for catalytic target accessibility and a short pathway for rapid diffusion, the utilization efficiency of cobalt nanoparticles inside the plate-like OMCs with short pore length is well improved, which can take full advantage of porous structure in electrocatalysis and increase the utilization of catalysts. The active sites in N/Co/OMCs for oxygen reduction reaction (ORR) are highly exposed to oxygen molecule, which results in a high activity for ORR. By combination of the catalytic properties of nitrogen dopant, incorporation of Co nanoparticles, and structural properties of OMCs, the N/Co/plate-like OMCs are highly active noble-metal free catalysts for ORR in alkaline solution. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(No.40120631)Natural Science Foundation of Hubei Province(No.20211j0188).
文摘Zeolitic-imidazole frameworks(ZIFs)derivations have widely emerged as an efficient air cathode of zinc-air batteries(ZABs)due to excellent bifunctional oxygen electrocatalysis performance.However,they are not stable enough for long-term operation of rechargeable ZABs because of weak association with current collector,especially under bending conditions for flexible ZAB devices.Here,we show that by purposely designing coordinatively unsaturated ZIFs via a facile morphology regulation,which can be chemically linked on acid-treated carbon cloth,a stable Co-N-C air cathode is therefore derived where Co nanoparticles(NPs)are uniformly confined within the Co-N-C matrix on carbon cloth(Co/Co-N-C/CC).Specifically,when without being stabilized from carbon cloth,the pyrolysis of ZIFs with different unsaturated coordination levels has a negligible impact on the bifunctional oxygen-catalyzed performance.The optimal Co/Co-N-C/CC catalyst assembled ZAB possesses a large open circuit voltage of 1.415 V and a high peak power density of 163 mW·cm^(−2) as well as excellent cycling durability upon 630 discharge–charge cycles with 61%voltage efficiency remained,largely exceeding those of a benchmark Pt/C-IrO_(2) catalyst assembled ZAB.The synergy between Co NPs and active Co-N-C sites via electronic interaction induces the outstanding bifunctional oxygen-catalyzed activity and cathode performance.The present work highlights the importance of unsaturated coordination structures in ZIFs precursors for the performance of derived nanostructures in integrated electrodes.
文摘将三聚氰胺和Co的硝酸盐均质化混合后在N2氛围下热处理,使用H_(2)O_(2)对材料刻蚀后制得一种钴掺杂氮碳材料。经过扫描电镜、X射线衍射分析、X射线光电子能谱分析等测试显示材料为一种碳纳米管结构。电化学性能测试显示催化剂氧还原反应主要依靠四电子反应。线性扫描伏安测试显示半坡电位为832 mV,但是其功率密度为6.0 m A·cm^(-2),显示出该催化剂的氧还原能力,其抗甲醇能力和稳定性也优于商业化的Pt/C催化剂。
基金supported by the National Nature Science Foundation of China(51474255)the Hunan Provincial Science and Technology Plan Project,China(2016TP1007)the Open Research Fund Program of Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,China(Central South University),Ministry of Education,the Fundamental Research Funds for the Central Universities of Central South University,China~~
基金financially supported by the Natural Science Foundation of Anhui Province(KJ2018A0534)the research fund of Anhui Science and Technology University(ZRC2014402)+1 种基金Materials Science and Engineering Key Discipline Foundation(AKZDXK2015A01)the Deanship of Scientific Research at King Saud University for its funding of this research through the Research Group Project No.Prolific Research Group No.1436-011
文摘Lithium-ion batteries(LIBs) are considered new generation of large-scale energy-storage devices.However,LIBs suffer from a lack of desirable anode materials with excellent specific capacity and cycling stability.In this work,we design a novel hierarchical structure constructed by encapsulating cobalt sulfide nanowires within nitrogen-doped porous branched carbon nanotubes(NBNTs)for LIBs.The unique hierarchical Co9S8@NBNT electrode displayed a reversible specific capacity of 1310 mAhg-1 at a current density of 0.1 Ag-1,and was able to maintain a stable reversible discharge capacity of 1109 mAhg-1 at a current density of 0.5 Ag-1 with coulombic efficiency reaching almost 100% for 200 cycles.The excellent rate and cycling capabilities can be ascribed to the hierarchical porosity of the one-dimensional Co9S8@NBNT internetworks,the incorporation of nitrogen doping,and the carbon nanotube confinement of the active cobalt sulfide nanowires offering a proximate electron pathway for the isolated nanoparticles and shielding of the cobalt sulfide nanowires from pulverization over long cycling periods.
基金supported by The Australian Research Council(ARC)under project FL170100101The University of Queensland for o ering UQI Scholarship
文摘Conversion-type anode materials with a high charge storage capability generally su er from large volume expansion, poor electron conductivity, and sluggish metal ion transport kinetics. The electrode material described in this paper, namely cobalt sulphide nanoparticles encapsulated in carbon cages(Co9S8@NC), can circumvent these problems. This electrode material exhibited a reversible sodium-ion storage capacity of 705 mAh g^-1 at 100 mA g^-1 with an extraordinary rate capability and good cycling stability. Mechanistic study using the in situ transmission electron microscope technique revealed that the volumetric expansion of the Co9S8 nanoparticles is bu ered by the carbon cages, enabling a stable electrode–electrolyte interface. In addition, the carbon shell with high-content doped nitrogen significantly enhances the electron conductivity of the Co9S8@NC electrode material and provides doping-induced active sites to accommodate sodium ions. By integrating the Co9S8@NC as negative electrode with a cellulose-derived porous hard carbon/graphene oxide composite as positive electrode and 1 M NaPF6 in diglyme as the electrolyte, the sodium-ion capacitor full cell can achieve energy densities of 101.4 and 45.8 Wh kg^-1 at power densities of 200 and 10,000 W kg^-1, respectively.
基金financially supported by the National Natural Science Foundation of China (Nos. 21506081, 21705058, 21676126)the Provincial Natural Science Foundation of Jiangsu (Nos. BK20170524, BK20160492)+2 种基金China Postdoctoral Science Foundation (No. 2018T110450)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsThe financial support from an ARC Discovery Project (No. DP180102003)
文摘Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets(Co/N-Pg) is fabricated for Zn–air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap(0.81 V at 50 mA cm^-2) and high peak power density(119 mW cm^-2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.
基金financial support from the National Natural Science Foundation of China(21405011)the Science and Technology Development Planning of Jilin Province(20150520014JH)
文摘In this work, nitrogen-doped cobalt nanoparticlesinitrogen-doped plate-like ordered mesoporous carbons (N/Co/OMCs) were used as noble-metal free electrocatalysts with high catalytic efficiency. Compared with OMCs with long channel length, due to more entrances for catalytic target accessibility and a short pathway for rapid diffusion, the utilization efficiency of cobalt nanoparticles inside the plate-like OMCs with short pore length is well improved, which can take full advantage of porous structure in electrocatalysis and increase the utilization of catalysts. The active sites in N/Co/OMCs for oxygen reduction reaction (ORR) are highly exposed to oxygen molecule, which results in a high activity for ORR. By combination of the catalytic properties of nitrogen dopant, incorporation of Co nanoparticles, and structural properties of OMCs, the N/Co/plate-like OMCs are highly active noble-metal free catalysts for ORR in alkaline solution. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
