Lithium sulfur(Li-S)batteries with high specific capacity and energy density can bring enormous opportunities for the nextgeneration energy storage systems.However,the severe dissolution and shuttle effect of lithium ...Lithium sulfur(Li-S)batteries with high specific capacity and energy density can bring enormous opportunities for the nextgeneration energy storage systems.However,the severe dissolution and shuttle effect of lithium polysulfides(LiPSs)is still the key issue that seriously impedes the development of practical Li-S batteries.Here,polar Co9S8 inlaid carbon nanoboxes(Co9S8@C NBs)have been investigated as cathode host for high-performance Li-S batteries.In this integrated structure,Co9S8 nanocrystals not only provide strong chemisorptive capability for polar LiPSs,but also act as a catalyst to accelerate polysulfide redox reactions;while carbon nanobox with large inner space can offer enough space to relieve the volume expansion and physically confine LiPSs’dissolution.As a result,the S/Co9S8@C NBs cathode exhibits high specific capacity at 1C and the capacity retention was^83%after 400 cycles,corresponding to an average decay rate of only^0.043%per cycle.展开更多
Formaldehyde(FA),as an important chemical raw material,has been widely used in many fields.However,the discharge of a large amount of FA-containing wastewater poses a serious threat to the environment and human health...Formaldehyde(FA),as an important chemical raw material,has been widely used in many fields.However,the discharge of a large amount of FA-containing wastewater poses a serious threat to the environment and human health.Recently,the in-situ hydrogen energy release technology of hydrogen-containing stable liquid has been extensively explored due to its safe storage.Exploring a robust method to achieve FA removal and synchronous in-situ hydrogen release from FA containing wastewater is of great significant for environmental protection and energy crisis alleviation.Here,we have innovatively introduced peroxymonosulfate(PMS)activation technology into FA removal and hydrogen production simultaneously.The composite of nitrogen doped carbon coating Co_(9)S_(8)nanotubes(Co_(9)S_(8)@N-C)is employed as a proof of concept for FA decomposition and simultaneously hydrogen production based on PMS activation system.As expected,the Co_(9)S_(8)@N-C/PMS system presents much superior hydrogen production efficiency and satisfactory FA removal rate towards FA wastewater than those of common catalysis,photocatalysis and Fenton reaction in the basic condition in a wide range of FA concentration.The hydrogen yield reaches a value as high as 471μmol within 60 min,corresponding to a FA degradation rate of 30%with an initial FA concentration of 0.722 mol L^(-1).Characterizations and density functional theory(DFT)calculations suggest that the free radical process dominated by superoxide radical(O_(2)·^(-))and nonradical process dominated by singlet oxygen(^(1)O_(2)),which are induced by Co_(9)S_(8)@N-C/PMS system,are responsible for highly efficient hydrogen production via FA degradation.These generated O_(2)·^(-)and ^(1)O_(2)can extract·H from FA to form·OOH intermediate,which can further combine with the·H from water to produce hydrogen.This study provides an applicable technique for environmental purification and new energy development based on FA containing wastewater.展开更多
低成本、高性能的钠离子电池有望成为代替锂离子电池的下一代核心器件.但是开发出高比容量、高倍率的钠离子电池负极材料依然是瓶颈.本文通过水热/溶剂热法制备了Co基前驱体,然后将其一步硫/磷热处理制得具有空心多孔结构的h-Co_(9)S_(8...低成本、高性能的钠离子电池有望成为代替锂离子电池的下一代核心器件.但是开发出高比容量、高倍率的钠离子电池负极材料依然是瓶颈.本文通过水热/溶剂热法制备了Co基前驱体,然后将其一步硫/磷热处理制得具有空心多孔结构的h-Co_(9)S_(8)/CoP/C纳米复合材料.通过X-射线粉末衍射(XRD)、拉曼光谱(Raman)、扫描电镜(SEM)、透射电镜(TEM)和X-射线光电子能谱(XPS)等表征以确定纳米复合物的物相以及形貌特征.当h-Co_(9)S_(8)/CoP/C作为钠离子电池负极材料时,该电极材料展示了高的比容量(561 mAh g^(-1)@0.1 Ag^(-1))、较好的循环性能(可逆比容量200 mAh g^(-1)@2 Ag^(-1))和倍率性能.h-Co_(9)S_(8)/CoP/C之所以显示出良好的储钠性能,主要得益于其空心多孔结构不仅提供更多的空间缓解钠在反复嵌入和脱出过程造成的体积膨胀效应,而且可以缩短离子/电荷扩散途径以加快反应动力学,此外,Co_(9)S_(8)、CoP和C独特的电子结构优势得以共同发挥.展开更多
基金The authors acknowledge the financial support from the National Postdoctoral Program for Innovation Talents(No.BX201700103)China Postdoctoral Science Foundation funded project(No.2018M633664).
文摘Lithium sulfur(Li-S)batteries with high specific capacity and energy density can bring enormous opportunities for the nextgeneration energy storage systems.However,the severe dissolution and shuttle effect of lithium polysulfides(LiPSs)is still the key issue that seriously impedes the development of practical Li-S batteries.Here,polar Co9S8 inlaid carbon nanoboxes(Co9S8@C NBs)have been investigated as cathode host for high-performance Li-S batteries.In this integrated structure,Co9S8 nanocrystals not only provide strong chemisorptive capability for polar LiPSs,but also act as a catalyst to accelerate polysulfide redox reactions;while carbon nanobox with large inner space can offer enough space to relieve the volume expansion and physically confine LiPSs’dissolution.As a result,the S/Co9S8@C NBs cathode exhibits high specific capacity at 1C and the capacity retention was^83%after 400 cycles,corresponding to an average decay rate of only^0.043%per cycle.
基金the National Natural Science Foundation of China(Nos.21975193 and 51602237)the Fundamental Research Funds for the Central Universities,China(WUT:2021Ⅲ034JC)。
文摘Formaldehyde(FA),as an important chemical raw material,has been widely used in many fields.However,the discharge of a large amount of FA-containing wastewater poses a serious threat to the environment and human health.Recently,the in-situ hydrogen energy release technology of hydrogen-containing stable liquid has been extensively explored due to its safe storage.Exploring a robust method to achieve FA removal and synchronous in-situ hydrogen release from FA containing wastewater is of great significant for environmental protection and energy crisis alleviation.Here,we have innovatively introduced peroxymonosulfate(PMS)activation technology into FA removal and hydrogen production simultaneously.The composite of nitrogen doped carbon coating Co_(9)S_(8)nanotubes(Co_(9)S_(8)@N-C)is employed as a proof of concept for FA decomposition and simultaneously hydrogen production based on PMS activation system.As expected,the Co_(9)S_(8)@N-C/PMS system presents much superior hydrogen production efficiency and satisfactory FA removal rate towards FA wastewater than those of common catalysis,photocatalysis and Fenton reaction in the basic condition in a wide range of FA concentration.The hydrogen yield reaches a value as high as 471μmol within 60 min,corresponding to a FA degradation rate of 30%with an initial FA concentration of 0.722 mol L^(-1).Characterizations and density functional theory(DFT)calculations suggest that the free radical process dominated by superoxide radical(O_(2)·^(-))and nonradical process dominated by singlet oxygen(^(1)O_(2)),which are induced by Co_(9)S_(8)@N-C/PMS system,are responsible for highly efficient hydrogen production via FA degradation.These generated O_(2)·^(-)and ^(1)O_(2)can extract·H from FA to form·OOH intermediate,which can further combine with the·H from water to produce hydrogen.This study provides an applicable technique for environmental purification and new energy development based on FA containing wastewater.
文摘低成本、高性能的钠离子电池有望成为代替锂离子电池的下一代核心器件.但是开发出高比容量、高倍率的钠离子电池负极材料依然是瓶颈.本文通过水热/溶剂热法制备了Co基前驱体,然后将其一步硫/磷热处理制得具有空心多孔结构的h-Co_(9)S_(8)/CoP/C纳米复合材料.通过X-射线粉末衍射(XRD)、拉曼光谱(Raman)、扫描电镜(SEM)、透射电镜(TEM)和X-射线光电子能谱(XPS)等表征以确定纳米复合物的物相以及形貌特征.当h-Co_(9)S_(8)/CoP/C作为钠离子电池负极材料时,该电极材料展示了高的比容量(561 mAh g^(-1)@0.1 Ag^(-1))、较好的循环性能(可逆比容量200 mAh g^(-1)@2 Ag^(-1))和倍率性能.h-Co_(9)S_(8)/CoP/C之所以显示出良好的储钠性能,主要得益于其空心多孔结构不仅提供更多的空间缓解钠在反复嵌入和脱出过程造成的体积膨胀效应,而且可以缩短离子/电荷扩散途径以加快反应动力学,此外,Co_(9)S_(8)、CoP和C独特的电子结构优势得以共同发挥.
