以间苯二酚、甲醛为前驱体,通过溶胶凝胶法,采用CO2超临界干燥、冷冻干燥、常压干燥制备碳气凝胶.采用N2低温吸脱附法、四探针法、扫描电镜对碳气凝胶的电导率、孔结构等进行考察,研究碳气凝胶作为导电剂材料对锂-二氧化锰电池大电流放...以间苯二酚、甲醛为前驱体,通过溶胶凝胶法,采用CO2超临界干燥、冷冻干燥、常压干燥制备碳气凝胶.采用N2低温吸脱附法、四探针法、扫描电镜对碳气凝胶的电导率、孔结构等进行考察,研究碳气凝胶作为导电剂材料对锂-二氧化锰电池大电流放电性能的影响.结果表明:不同干燥方法制备的碳气凝胶电阻率相近,比表面积差异较大,CO2超临界干燥制备的碳气凝胶比表面积最大(1 017.85 m2/g);以CO2超临界干燥制备的碳气凝胶为导电剂的电池放电比容量最大,100 m A恒流放电比容量达到101 m Ah/g,其放电平台比常压干燥的碳气凝胶高80 m V左右,1 m A恒流放电比容量则差异较小.结果显示碳气凝胶导电剂比商业乙炔黑导电剂性能更优.展开更多
Through in situ redox deposition and growth of MnO2 nanostructures on hierarchically porous carbon （HPC）, a MnOR/HPC hybrid has been synthesized and employed as cathode catalyst for non-aqueous Li-O2 batteries. Owin...Through in situ redox deposition and growth of MnO2 nanostructures on hierarchically porous carbon （HPC）, a MnOR/HPC hybrid has been synthesized and employed as cathode catalyst for non-aqueous Li-O2 batteries. Owing to the mild synthetic conditions, MnO2 was uniformly distributed on the surface of the carbon support, without destroying the hierarchical porous nanostructure. As a result, the as-prepared MnO2/HPC nanocomposite exhibits excellent Li-O2 battery performance, including low charge overpotential, good rate capacity and long cycle stability up to 300 cycles with controlling capacity of 1,000 mAh·g^-1. A combination of the multi-scale porous network of the shell-connected carbon support and the highly dispersed MnO2 nanostructure benefits the transportation of ions, oxygen and electrons and contributes to the excellent electrode performance.展开更多
Tubular nanocomposite with interconnected MnO2 nanoflakes coated on MWCNTs(MWCNTs@MnO2)was fabricated by an aqueous solution method at 80°C.Scanning electron microscopy,X-ray diffraction and galvanostatic charge-...Tubular nanocomposite with interconnected MnO2 nanoflakes coated on MWCNTs(MWCNTs@MnO2)was fabricated by an aqueous solution method at 80°C.Scanning electron microscopy,X-ray diffraction and galvanostatic charge-discharge tests were used to characterize the structures and electrochemical performances of the as-prepared nanocomposite.The capacity reaches 1233.6 mA h g-1 at a current density of 100 mA g-1 for the first discharge,and it can still maintain a capacity of 633.1mA h g-1 after 100 charge-discharge cycles.The results show that MWCNTs with good electrical conductivity as anchors of MnO2 can provide fast electron transport channels for MnO2 in the electrochemical reactions,and the as-prepared MWCNTs@MnO2 nanocomposite is a potential anode material for lithium ion batteries.展开更多
文摘以间苯二酚、甲醛为前驱体,通过溶胶凝胶法,采用CO2超临界干燥、冷冻干燥、常压干燥制备碳气凝胶.采用N2低温吸脱附法、四探针法、扫描电镜对碳气凝胶的电导率、孔结构等进行考察,研究碳气凝胶作为导电剂材料对锂-二氧化锰电池大电流放电性能的影响.结果表明:不同干燥方法制备的碳气凝胶电阻率相近,比表面积差异较大,CO2超临界干燥制备的碳气凝胶比表面积最大(1 017.85 m2/g);以CO2超临界干燥制备的碳气凝胶为导电剂的电池放电比容量最大,100 m A恒流放电比容量达到101 m Ah/g,其放电平台比常压干燥的碳气凝胶高80 m V左右,1 m A恒流放电比容量则差异较小.结果显示碳气凝胶导电剂比商业乙炔黑导电剂性能更优.
文摘Through in situ redox deposition and growth of MnO2 nanostructures on hierarchically porous carbon （HPC）, a MnOR/HPC hybrid has been synthesized and employed as cathode catalyst for non-aqueous Li-O2 batteries. Owing to the mild synthetic conditions, MnO2 was uniformly distributed on the surface of the carbon support, without destroying the hierarchical porous nanostructure. As a result, the as-prepared MnO2/HPC nanocomposite exhibits excellent Li-O2 battery performance, including low charge overpotential, good rate capacity and long cycle stability up to 300 cycles with controlling capacity of 1,000 mAh·g^-1. A combination of the multi-scale porous network of the shell-connected carbon support and the highly dispersed MnO2 nanostructure benefits the transportation of ions, oxygen and electrons and contributes to the excellent electrode performance.
基金supported by the National Natural Science Foundation of China(Grant Nos.11179038 and 10974073)the Specialized Re-search Fund for the Doctoral Program of Higher Education(Grant No.20120211130005)
文摘Tubular nanocomposite with interconnected MnO2 nanoflakes coated on MWCNTs(MWCNTs@MnO2)was fabricated by an aqueous solution method at 80°C.Scanning electron microscopy,X-ray diffraction and galvanostatic charge-discharge tests were used to characterize the structures and electrochemical performances of the as-prepared nanocomposite.The capacity reaches 1233.6 mA h g-1 at a current density of 100 mA g-1 for the first discharge,and it can still maintain a capacity of 633.1mA h g-1 after 100 charge-discharge cycles.The results show that MWCNTs with good electrical conductivity as anchors of MnO2 can provide fast electron transport channels for MnO2 in the electrochemical reactions,and the as-prepared MWCNTs@MnO2 nanocomposite is a potential anode material for lithium ion batteries.
