硬炭凭借较高的储钠容量、低电压平台以及优异的循环稳定性成为了钠离子电池(SIBs)最具应用潜力的负极材料。硬炭材料的微观孔隙结构是影响其储钠性能的关键因素之一,合理调控硬炭材料的孔隙结构大小及分布对提升钠离子电池性能至关重...硬炭凭借较高的储钠容量、低电压平台以及优异的循环稳定性成为了钠离子电池(SIBs)最具应用潜力的负极材料。硬炭材料的微观孔隙结构是影响其储钠性能的关键因素之一,合理调控硬炭材料的孔隙结构大小及分布对提升钠离子电池性能至关重要。本文以β-环糊精为碳源,采用NaCl辅助水热法制备了一系列具有不同微观孔隙结构的硬炭材料,考察了NaCl浓度对硬炭微观孔隙结构的影响,研究了硬炭材料的储纳性能。采用非原位X射线衍射仪、拉曼光谱仪及高倍率透射电镜等进行表征,结果表明,调控NaCl浓度能够优化硬炭材料的孔隙结构,提升硬炭材料闭孔体积。当NaCl浓度为2mol L^(-1)时,制备的硬炭材料(CD-2)的无序程度与石墨微晶尺寸最大,具有最大的闭孔体积与梯度孔隙结构。电化学测试表明,在0.02Ag^(-1)的电流密度下,CD-2硬炭材料具有360 mA hg^(-1)的高储钠比容量及90.2%的首次库伦效率。提出的NaCl辅助水热炭化调控硬炭闭孔结构的策略,为硬炭材料孔隙结构的合理设计提供了有效的技术方法,指导了高性能SIBs硬炭负极材料的开发。展开更多
针对回填石和海淡水复杂介质环境中铝合金牺牲阳极对沉管隧道钢壳的长期保护效果,建立了1∶80物理缩比模型,采用加速电解方法模拟不同服役周期下的保护性能,并测试和分析了钢壳保护电位分布、介质电阻率变化及阳极溶解形貌。结果表明:...针对回填石和海淡水复杂介质环境中铝合金牺牲阳极对沉管隧道钢壳的长期保护效果,建立了1∶80物理缩比模型,采用加速电解方法模拟不同服役周期下的保护性能,并测试和分析了钢壳保护电位分布、介质电阻率变化及阳极溶解形貌。结果表明:初期钢壳保护电位在-1.0 V(vs.Ag/Ag Cl/海水电极,下同)以下,并随服役时间延长逐渐正移,末期平均保护电位为-0.91 V,但全周期(100 a)内始终满足电位低于-800 m V的阴极保护准则;随服役时间的延长,介质环境电阻率显著升高,由初期的66Ω·cm增至末期的146Ω·cm,牺牲阳极表现出稳定的电化学性能,末期电位仍保持负于-1.05 V,溶解形貌基本均匀,但因阳极尺寸缩减和介质电阻率升高,发生电流由40 m A降至11 m A。展开更多
In the process of protecting ferrous materials,aluminum coating usually forms a dense oxide film on the surface of the iron-based alloy.However,the capacity of the sacrificial anode is rather insufficient.In order to ...In the process of protecting ferrous materials,aluminum coating usually forms a dense oxide film on the surface of the iron-based alloy.However,the capacity of the sacrificial anode is rather insufficient.In order to solve this problem,the microstructure and electrochemical corrosion properties of Al-8Si-3Fe-xIn alloy under low chlorine conditions were studied.The results show that indium(In)dissolves to form In^(3+)and In^(+)reverse plating on the surface of the bare substrate to form a passivation film defect.When the In content is high,the segregated In forms an activation point in the form of a cathode phase.In activatesτ_(6)phase to form a micro-couple,which improves the non-uniform corrosion.The In-containing corrosion products at the phase boundary hinder the diffusion of Cl−.With an increase of In content,the self-corrosion potential(Ecorr)of the alloy shifts negatively,and the self-corrosion current density(Jcorr)decreases from 6.477μA/cm^(2)to 1.352μA/cm^(2),and then increases gradually.However,when the In content is 0.1%,the Ecorr of the alloy changes from−0.824 V to−0.932 V,and the Jcorr decreases from 6.477μA/cm^(2)to 4.699μA/cm^(2),suggesting that the use of sacrificial anode will give the best effect.展开更多
TiO2-B was synthesized by solid-state reaction. The structures, surface morphologies and electrochemical performances of TiO2-B were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） ...TiO2-B was synthesized by solid-state reaction. The structures, surface morphologies and electrochemical performances of TiO2-B were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electrochemical measurement, respectively. The effects of calcining temperature, molar ratio of K2O to TiO2 and calcining time on the characteristics of TiO2-B were investigated. The results show that the calcining time exerts a significant influence on the electrochemical performances of TiO2-B. The TiO2-B is obtained with good crystal structure and suitable size by using K2Ti4O9, which is prepared at 950 ℃for 24 h under the condition of x（K2O）/x（TiO2）=1：3.5. The TiO2-B delivers all initial discharge capacity of 231.6 mA.h/g. And the rate caoacitv is 73.2 mA-h/g at 1 675 mA/g, which suggests that TiO2-B is a promising anode material for the lithium ion batteries.展开更多
文摘硬炭凭借较高的储钠容量、低电压平台以及优异的循环稳定性成为了钠离子电池(SIBs)最具应用潜力的负极材料。硬炭材料的微观孔隙结构是影响其储钠性能的关键因素之一,合理调控硬炭材料的孔隙结构大小及分布对提升钠离子电池性能至关重要。本文以β-环糊精为碳源,采用NaCl辅助水热法制备了一系列具有不同微观孔隙结构的硬炭材料,考察了NaCl浓度对硬炭微观孔隙结构的影响,研究了硬炭材料的储纳性能。采用非原位X射线衍射仪、拉曼光谱仪及高倍率透射电镜等进行表征,结果表明,调控NaCl浓度能够优化硬炭材料的孔隙结构,提升硬炭材料闭孔体积。当NaCl浓度为2mol L^(-1)时,制备的硬炭材料(CD-2)的无序程度与石墨微晶尺寸最大,具有最大的闭孔体积与梯度孔隙结构。电化学测试表明,在0.02Ag^(-1)的电流密度下,CD-2硬炭材料具有360 mA hg^(-1)的高储钠比容量及90.2%的首次库伦效率。提出的NaCl辅助水热炭化调控硬炭闭孔结构的策略,为硬炭材料孔隙结构的合理设计提供了有效的技术方法,指导了高性能SIBs硬炭负极材料的开发。
文摘针对回填石和海淡水复杂介质环境中铝合金牺牲阳极对沉管隧道钢壳的长期保护效果,建立了1∶80物理缩比模型,采用加速电解方法模拟不同服役周期下的保护性能,并测试和分析了钢壳保护电位分布、介质电阻率变化及阳极溶解形貌。结果表明:初期钢壳保护电位在-1.0 V(vs.Ag/Ag Cl/海水电极,下同)以下,并随服役时间延长逐渐正移,末期平均保护电位为-0.91 V,但全周期(100 a)内始终满足电位低于-800 m V的阴极保护准则;随服役时间的延长,介质环境电阻率显著升高,由初期的66Ω·cm增至末期的146Ω·cm,牺牲阳极表现出稳定的电化学性能,末期电位仍保持负于-1.05 V,溶解形貌基本均匀,但因阳极尺寸缩减和介质电阻率升高,发生电流由40 m A降至11 m A。
基金Projects(52171003,52271005)supported by the National Science and Technology Major Project of ChinaProject(KYCX23_3032)supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China。
文摘In the process of protecting ferrous materials,aluminum coating usually forms a dense oxide film on the surface of the iron-based alloy.However,the capacity of the sacrificial anode is rather insufficient.In order to solve this problem,the microstructure and electrochemical corrosion properties of Al-8Si-3Fe-xIn alloy under low chlorine conditions were studied.The results show that indium(In)dissolves to form In^(3+)and In^(+)reverse plating on the surface of the bare substrate to form a passivation film defect.When the In content is high,the segregated In forms an activation point in the form of a cathode phase.In activatesτ_(6)phase to form a micro-couple,which improves the non-uniform corrosion.The In-containing corrosion products at the phase boundary hinder the diffusion of Cl−.With an increase of In content,the self-corrosion potential(Ecorr)of the alloy shifts negatively,and the self-corrosion current density(Jcorr)decreases from 6.477μA/cm^(2)to 1.352μA/cm^(2),and then increases gradually.However,when the In content is 0.1%,the Ecorr of the alloy changes from−0.824 V to−0.932 V,and the Jcorr decreases from 6.477μA/cm^(2)to 4.699μA/cm^(2),suggesting that the use of sacrificial anode will give the best effect.
基金Project(2007BAE12B01) supported by the National Key Technology R&D Program of China
文摘TiO2-B was synthesized by solid-state reaction. The structures, surface morphologies and electrochemical performances of TiO2-B were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electrochemical measurement, respectively. The effects of calcining temperature, molar ratio of K2O to TiO2 and calcining time on the characteristics of TiO2-B were investigated. The results show that the calcining time exerts a significant influence on the electrochemical performances of TiO2-B. The TiO2-B is obtained with good crystal structure and suitable size by using K2Ti4O9, which is prepared at 950 ℃for 24 h under the condition of x（K2O）/x（TiO2）=1：3.5. The TiO2-B delivers all initial discharge capacity of 231.6 mA.h/g. And the rate caoacitv is 73.2 mA-h/g at 1 675 mA/g, which suggests that TiO2-B is a promising anode material for the lithium ion batteries.
