采用水热法制备了具有二维层状结构的钙钒青铜(CaxV2O5·n H2O,CVO)水系锌离子电池钒基正极材料,并通过调控前驱体溶液中碳纳米管的含量,得到3种钙钒青铜/碳纳米管复合材料(CVO@CNTs).利用X射线衍射、热重分析、扫描电子显微镜和透...采用水热法制备了具有二维层状结构的钙钒青铜(CaxV2O5·n H2O,CVO)水系锌离子电池钒基正极材料,并通过调控前驱体溶液中碳纳米管的含量,得到3种钙钒青铜/碳纳米管复合材料(CVO@CNTs).利用X射线衍射、热重分析、扫描电子显微镜和透射电子显微镜等对材料进行了表征.结果表明,所制备的CVO呈纳米带形貌,长约十几微米,宽约几百纳米,选区电子衍射测试表明所得材料为单晶结构.循环伏安测试结果表明,CVO和CVO@CNTs均具有多个氧化还原峰,储锌机制包括赝电容行为和电池行为.在放电倍率1C (1C=300 m A/g)测试条件下,CVO纳米带比容量稳定在210. 1 m A·h/g;与CNTs复合后,CVO@CNTs复合材料的电荷转移阻抗降低,在相同测试条件下表现出更高的比容量和优异的倍率性能.其中,CVO@CNTs-40表现出最高的比容量,在1C倍率测试条件下的比容量可达274. 3 m A·h/g,即使在20C的测试条件下放电比容量仍可达85. 2 m A·h/g,且循环1000次后容量保持率能达到92%.展开更多
由Inorgonic Chiemistry Fronhens(ICF)期刊和南开大学化学学院联合主办的无机化学前沿编委会暨化学及交叉学科前沿国际研讨会于2019年9月23〜25 H在天津召开。无机化学前沿国际研讨会是ICF期刊主办的系列学术会议。该期刊由中国化学会...由Inorgonic Chiemistry Fronhens(ICF)期刊和南开大学化学学院联合主办的无机化学前沿编委会暨化学及交叉学科前沿国际研讨会于2019年9月23〜25 H在天津召开。无机化学前沿国际研讨会是ICF期刊主办的系列学术会议。该期刊由中国化学会、北京大学和英国皇家化学会(Royal Society of Chemistry)合作出版。无机化学前沿国际研讨会致力于探讨当今无机化学前沿及其与其他学科交叉研究领域的热点问题、最新进展和发展趋势。展开更多
利用水热合成的方法,使用新型的表面活性剂十六烷基三甲基对苯磺酸盐作为模板剂合成了高质量的MCM-48介孔分子筛,并用X-射线衍射(XRD)、扫描电镜(SEM)、高分辨透射电镜(HRTEM)以及N2吸附-脱附进行了表征。合成过程的研究表明该合成体系...利用水热合成的方法,使用新型的表面活性剂十六烷基三甲基对苯磺酸盐作为模板剂合成了高质量的MCM-48介孔分子筛,并用X-射线衍射(XRD)、扫描电镜(SEM)、高分辨透射电镜(HRTEM)以及N2吸附-脱附进行了表征。合成过程的研究表明该合成体系经历了三相,起始相为具有六方对称性的MCM-41,随着加热时间的延长,生成了具有立方对称性的MCM-48,进一步延长加热时间则生成了层状相MCM-50。三相转变发生的核心驱动力来自于表面活性剂有效堆积参数g因子的改变,随着反应时间的延长,由于对甲基苯磺酸根离子(Tos-)的流失,表面活性剂极性头所占的有效面积(a0)明显减小,g值变大。另外,XRD、傅立叶变换的红外光谱(FT-IR)以及固体魔角自旋核磁共振(^(29)Si MAS NMR)的表征结果证明:随着晶化时间的延长,相转变的同时伴随着介孔材料的孔壁逐渐由原子无序的非晶态向原子有序的晶态结构转变。最终形成的原子有序层状介孔分子筛可以作为扩孔型微孔分子筛合成的有效前驱体。展开更多
Rechargeable lithium-oxygen(Li-O_(2))batteries have attracted wide attention due to their high energy density.However,the sluggish cathode kinetics results in high overvoltage and poor cycling performance.Ruthenium(Ru...Rechargeable lithium-oxygen(Li-O_(2))batteries have attracted wide attention due to their high energy density.However,the sluggish cathode kinetics results in high overvoltage and poor cycling performance.Ruthenium(Ru)-based electrocatalysts have been demonstrated to be promising cathode catalysts to promote oxygen evolution reaction(OER).It facilitates decomposition of lithium peroxide(Li_(2)O_(2))by adjusting Li_(2)O_(2) morphologies,which is due to the strong interaction between Ru-based catalyst and superoxide anion(O_(2))intermediate.In this review,the design strategies of Ru-based electrocatalysts are introduced to enhance their OER catalytic kinetics in Li-O_(2) batteries.Different configurations of Ru-based catalysts,including metal particles(Ru metal and alloys),single-atom catalysts,and Ru-loaded compounds with various substrates(carbon materials,metal oxides/sulfides),have been summarized to regulate the electronic structure and the matrix architecture of the Ru-based electrocatalysts.The structure-property relationship of Ru-based catalysts is discussed for a better understanding of the Li_(2)O_(2) decomposition mechanism at the cathode interface.Finally,the challenges of Ru-based electrocatalysts are proposed for the future development of Li-O_(2) batteries.展开更多
文摘采用水热法制备了具有二维层状结构的钙钒青铜(CaxV2O5·n H2O,CVO)水系锌离子电池钒基正极材料,并通过调控前驱体溶液中碳纳米管的含量,得到3种钙钒青铜/碳纳米管复合材料(CVO@CNTs).利用X射线衍射、热重分析、扫描电子显微镜和透射电子显微镜等对材料进行了表征.结果表明,所制备的CVO呈纳米带形貌,长约十几微米,宽约几百纳米,选区电子衍射测试表明所得材料为单晶结构.循环伏安测试结果表明,CVO和CVO@CNTs均具有多个氧化还原峰,储锌机制包括赝电容行为和电池行为.在放电倍率1C (1C=300 m A/g)测试条件下,CVO纳米带比容量稳定在210. 1 m A·h/g;与CNTs复合后,CVO@CNTs复合材料的电荷转移阻抗降低,在相同测试条件下表现出更高的比容量和优异的倍率性能.其中,CVO@CNTs-40表现出最高的比容量,在1C倍率测试条件下的比容量可达274. 3 m A·h/g,即使在20C的测试条件下放电比容量仍可达85. 2 m A·h/g,且循环1000次后容量保持率能达到92%.
文摘由Inorgonic Chiemistry Fronhens(ICF)期刊和南开大学化学学院联合主办的无机化学前沿编委会暨化学及交叉学科前沿国际研讨会于2019年9月23〜25 H在天津召开。无机化学前沿国际研讨会是ICF期刊主办的系列学术会议。该期刊由中国化学会、北京大学和英国皇家化学会(Royal Society of Chemistry)合作出版。无机化学前沿国际研讨会致力于探讨当今无机化学前沿及其与其他学科交叉研究领域的热点问题、最新进展和发展趋势。
文摘利用水热合成的方法,使用新型的表面活性剂十六烷基三甲基对苯磺酸盐作为模板剂合成了高质量的MCM-48介孔分子筛,并用X-射线衍射(XRD)、扫描电镜(SEM)、高分辨透射电镜(HRTEM)以及N2吸附-脱附进行了表征。合成过程的研究表明该合成体系经历了三相,起始相为具有六方对称性的MCM-41,随着加热时间的延长,生成了具有立方对称性的MCM-48,进一步延长加热时间则生成了层状相MCM-50。三相转变发生的核心驱动力来自于表面活性剂有效堆积参数g因子的改变,随着反应时间的延长,由于对甲基苯磺酸根离子(Tos-)的流失,表面活性剂极性头所占的有效面积(a0)明显减小,g值变大。另外,XRD、傅立叶变换的红外光谱(FT-IR)以及固体魔角自旋核磁共振(^(29)Si MAS NMR)的表征结果证明:随着晶化时间的延长,相转变的同时伴随着介孔材料的孔壁逐渐由原子无序的非晶态向原子有序的晶态结构转变。最终形成的原子有序层状介孔分子筛可以作为扩孔型微孔分子筛合成的有效前驱体。
基金the National Natural Science Foundation of China(22325902 and 51671107)Haihe Laboratory of Sustainable Chemical Transformations.
文摘Rechargeable lithium-oxygen(Li-O_(2))batteries have attracted wide attention due to their high energy density.However,the sluggish cathode kinetics results in high overvoltage and poor cycling performance.Ruthenium(Ru)-based electrocatalysts have been demonstrated to be promising cathode catalysts to promote oxygen evolution reaction(OER).It facilitates decomposition of lithium peroxide(Li_(2)O_(2))by adjusting Li_(2)O_(2) morphologies,which is due to the strong interaction between Ru-based catalyst and superoxide anion(O_(2))intermediate.In this review,the design strategies of Ru-based electrocatalysts are introduced to enhance their OER catalytic kinetics in Li-O_(2) batteries.Different configurations of Ru-based catalysts,including metal particles(Ru metal and alloys),single-atom catalysts,and Ru-loaded compounds with various substrates(carbon materials,metal oxides/sulfides),have been summarized to regulate the electronic structure and the matrix architecture of the Ru-based electrocatalysts.The structure-property relationship of Ru-based catalysts is discussed for a better understanding of the Li_(2)O_(2) decomposition mechanism at the cathode interface.Finally,the challenges of Ru-based electrocatalysts are proposed for the future development of Li-O_(2) batteries.
