Aqueous Zn batteries are promising candidates for grid-scale renewable energy storage.Foil electrodes have been widely investigated and applied as anode materials for aqueous Zn batteries,however,they suffer from limi...Aqueous Zn batteries are promising candidates for grid-scale renewable energy storage.Foil electrodes have been widely investigated and applied as anode materials for aqueous Zn batteries,however,they suffer from limited surface area and severe interfacial issues including metallic dendrites and corrosion side reactions,limiting the depth of discharge(DOD)of the foil electrode materials.Herein,a low-temperature replacement reaction is utilized to in-situ construct a three-dimensional(3D)corrosion-resistant interface for deeply rechargeable Zn foil electrodes.Specifically,the deliberate low-temperature environment controlled the replacement rate between polycrystalline Zn metal and oxalic acid,producing a Zn foil electrode with distinct 3D corrosion-resistant interface(3DCI-Zn),which differed from conventional two-dimensional(2D)protective structure and showed an order of magnitude higher surface area.Consequently,the 3DCI-Zn electrode exhibited dendrite-free and anticorrosion properties,and achieved stable plating/stripping performance for 1000 h at 10 mA cm^(-2)and 10 mAh cm^(-2)with a remarkable DOD of 79%.After pairing with a MnO2cathode with a high areal capacity of 4.2 mAh cm^(-2),the pouch cells delivered 168 Wh L^(-1)and a capacity retention of 89.7%after 100 cycles with a low negative/positive(N/P)ratio of 3:1.展开更多
With high energy density and improved safety,rechargeable battery chemistries with a zinc(Zn)metal anode offer promising and sustainable alternatives to those based on lithium metal or lithium-ion intercalation/alloyi...With high energy density and improved safety,rechargeable battery chemistries with a zinc(Zn)metal anode offer promising and sustainable alternatives to those based on lithium metal or lithium-ion intercalation/alloying anode materials;however,the poor electrochemical reversibility of Zn plating/stripping,induced by parasitic reactions with both aqueous and non-aqueous electrolytes,presently limits the practical appeal of these systems.Although recent efforts in rechargeable Zn metal batteries(RZMBs)have achieved certain advancements in Zn metal reversibility,as quantified by the Coulombic efficiency(CE),a standard protocol for CE has not been established,and results across chemistries and systems are often conflicting.More importantly,there is still an insufficient understanding regarding the critical factors dictating Zn reversibility.In this work,a rigorous,established protocol for determining CE of lithium metal anodes is transplanted to the Zn chemistry and is used for systematically examining how a series of factors including current collector chemistry,current density,temperature,and the upper voltage limit during stripping affect the measured reversibility of different Zn electrolytes.With support from density functional theory calculations,this standardized Zn CE protocol is then leveraged to identify an important correlation between electrolyte solvation strength toward Zn2+and the measured Zn CE in the corresponding electrolyte,providing new guidance for future development and evaluation of Zn electrolytes.展开更多
The tip vortices and aerodynamics of a NACA0012 wing in the vicinity of the ground were studied in a wind tunnel.The wing tip vortex structures and lift/drag forces were measured by a seven-hole probe and a force bala...The tip vortices and aerodynamics of a NACA0012 wing in the vicinity of the ground were studied in a wind tunnel.The wing tip vortex structures and lift/drag forces were measured by a seven-hole probe and a force balance,respectively.The evolution of the flow structures and aerodynamics with a ground height were analyzed.The vorticity of tip vortices was found to reduce with the decreasing of the ground height,and the position of vortex-core moved gradually to the outboard of the wing tip.Therefore,the down-wash flow induced by the tip vortices was weakened. However,vortex breakdown occurred as the wing lowered to the ground.From the experimental results of aerodynamics,the maximum lift-to-drag ratio was observed when the angle of attack was 2.5°and the ground clearance was 0.2.展开更多
基金financially supported by the National Natural Science Foundation of China (No.22205068,22109144)the“CUG Scholar”Scientific Research Funds at China University of Geosciences (Wuhan) (Project No.2022118)the Fundamental Research Funds for the Central Universities,China University of Geosciences (Wuhan) (No.162301202673)。
文摘Aqueous Zn batteries are promising candidates for grid-scale renewable energy storage.Foil electrodes have been widely investigated and applied as anode materials for aqueous Zn batteries,however,they suffer from limited surface area and severe interfacial issues including metallic dendrites and corrosion side reactions,limiting the depth of discharge(DOD)of the foil electrode materials.Herein,a low-temperature replacement reaction is utilized to in-situ construct a three-dimensional(3D)corrosion-resistant interface for deeply rechargeable Zn foil electrodes.Specifically,the deliberate low-temperature environment controlled the replacement rate between polycrystalline Zn metal and oxalic acid,producing a Zn foil electrode with distinct 3D corrosion-resistant interface(3DCI-Zn),which differed from conventional two-dimensional(2D)protective structure and showed an order of magnitude higher surface area.Consequently,the 3DCI-Zn electrode exhibited dendrite-free and anticorrosion properties,and achieved stable plating/stripping performance for 1000 h at 10 mA cm^(-2)and 10 mAh cm^(-2)with a remarkable DOD of 79%.After pairing with a MnO2cathode with a high areal capacity of 4.2 mAh cm^(-2),the pouch cells delivered 168 Wh L^(-1)and a capacity retention of 89.7%after 100 cycles with a low negative/positive(N/P)ratio of 3:1.
基金supported by the Joint Center for Energy Storage Research(JCESR),a Department of Energy,Energy Innovation Hub,under an Interagency Agreement No.IAA SN2020957Forch Distinguished Postdoctoral Fellowship administered by the National Research Councilsupport from Oak Ridge Associated Universities(ORAU)
文摘With high energy density and improved safety,rechargeable battery chemistries with a zinc(Zn)metal anode offer promising and sustainable alternatives to those based on lithium metal or lithium-ion intercalation/alloying anode materials;however,the poor electrochemical reversibility of Zn plating/stripping,induced by parasitic reactions with both aqueous and non-aqueous electrolytes,presently limits the practical appeal of these systems.Although recent efforts in rechargeable Zn metal batteries(RZMBs)have achieved certain advancements in Zn metal reversibility,as quantified by the Coulombic efficiency(CE),a standard protocol for CE has not been established,and results across chemistries and systems are often conflicting.More importantly,there is still an insufficient understanding regarding the critical factors dictating Zn reversibility.In this work,a rigorous,established protocol for determining CE of lithium metal anodes is transplanted to the Zn chemistry and is used for systematically examining how a series of factors including current collector chemistry,current density,temperature,and the upper voltage limit during stripping affect the measured reversibility of different Zn electrolytes.With support from density functional theory calculations,this standardized Zn CE protocol is then leveraged to identify an important correlation between electrolyte solvation strength toward Zn2+and the measured Zn CE in the corresponding electrolyte,providing new guidance for future development and evaluation of Zn electrolytes.
基金supported by the National Natural Science Foundation of China(11072142)Shanghai Program for Innovative Research Team in Universities
文摘The tip vortices and aerodynamics of a NACA0012 wing in the vicinity of the ground were studied in a wind tunnel.The wing tip vortex structures and lift/drag forces were measured by a seven-hole probe and a force balance,respectively.The evolution of the flow structures and aerodynamics with a ground height were analyzed.The vorticity of tip vortices was found to reduce with the decreasing of the ground height,and the position of vortex-core moved gradually to the outboard of the wing tip.Therefore,the down-wash flow induced by the tip vortices was weakened. However,vortex breakdown occurred as the wing lowered to the ground.From the experimental results of aerodynamics,the maximum lift-to-drag ratio was observed when the angle of attack was 2.5°and the ground clearance was 0.2.
基金financially supported by the National Natural Science Foundation of China(22205068 and 22109144)the"CUG Scholar"Scientific Research Funds at China University of Geosciences(Wuhan)(2022118)the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(162301202673)。
文摘寻找具有高本征活性的水氧化催化剂材料对许多清洁能源技术的发展至关重要.氢氧化物半导体对析氧反应具有一定的电催化活性.然而,该材料导电性较差,限制着其电催化本征活性的提升.本文提出一种兼具高导电性和高催化活性的半金属氢氧化物析氧电催化材料.通过阳离子掺杂和阴离子空位协同作用,镍铁水滑石半导体可转化为半金属材料,其电阻率降低了两个数量级.相应半金属氢氧化物阵列电极的电催化活性显著提升,在10 mA cm^(-2)电流密度下其析氧过电势仅为195 mV,Tafel斜率仅为40.9 mV dec^(-1),显著优于商用RuO_(2)催化剂(316 mV,99.6 mV dec^(-1)).原位拉曼光谱和理论计算结果表明,半金属氢氧化物可在较低过电位下转化为羟基氧化物中间体,有助于高价态金属活性位点的形成与稳定,从而提升材料的析氧本征活性.本研究表明,兼具优异导电性和催化活性的半金属氢氧化物可作为先进的电极材料.
