An asymmetrical supercapacitor （ASC）, comprising reduced graphene oxide （rGO）-encapsulated nickel phosphite hollow microspheres （NPOH-0.5@rGO） as positive electrode, and porous nitrogen/sulfur co-doped rGO aerog...An asymmetrical supercapacitor （ASC）, comprising reduced graphene oxide （rGO）-encapsulated nickel phosphite hollow microspheres （NPOH-0.5@rGO） as positive electrode, and porous nitrogen/sulfur co-doped rGO aerogel （NS-3D rGO） as negative electrode has been prepared. The NPOH-0.5@rGO electrode combines the advantages of the NPOH hollow microspheres and the conductive rGO layers giving rise to a large specific capacitance, high cycling reversibility, and excellent rate performance. The NS-3D rGO electrode with abundant porosity and active sites promotes electrolyte infiltration and broadens the working voltage range. The ASC （NPOH-0.5@rGO//NS-3D rGO） shows a maximum voltage of up to 1.4 V, outstanding cycling ability （capacitance retention of 95.5% after 10,000 cycles）, and excellent rate capability （capacitance retention of 77% as the current density is increased ten times）. The ASC can light up an light-emitting diodes （LED） for more than 20 min after charging for 20 s. The fabrication technique and device architecture can be extended to other active oxide and carbon-based materials for next-generation high-performance electrochemical storage devices.展开更多
本文通过调节烧结温度设计构筑了一种纳米多面体颗粒堆积的中空球状Li Ni0.5Mn1.5O4材料,并进一步通过碳纳米管(CNT)的改性来提高材料的循环性能和高倍率性能.纳米中空结构不仅减少了锂离子的扩散路径,也保证了电解液和正极材料的充分接...本文通过调节烧结温度设计构筑了一种纳米多面体颗粒堆积的中空球状Li Ni0.5Mn1.5O4材料,并进一步通过碳纳米管(CNT)的改性来提高材料的循环性能和高倍率性能.纳米中空结构不仅减少了锂离子的扩散路径,也保证了电解液和正极材料的充分接触,三维网状CNT的改性提高了材料的电子导电率,从而明显改善了材料的循环和高倍率性能.最终得到的LNMO-850/CNT材料在5 C的电流密度下初始容量为127 m A h g-1,500次循环后容量保持在104 m A h g-1.而在20 C的高电流密度下容量仍达到121 m A h g-1,体现了材料优异的循环和高倍率性能.展开更多
基金This work was jointly supported by the National Natural Science Foundation of China （No. 51572246）, Fundamental Research Funds for the Central Universi- ties （Nos. 53200859565, 53200859500 and 2652015425）, as well as City University of Hong Kong Applied Research Grant （ARG） （No. 9667122） and Strategic Research Grant （SRG） （No. 7004644）.
文摘An asymmetrical supercapacitor （ASC）, comprising reduced graphene oxide （rGO）-encapsulated nickel phosphite hollow microspheres （NPOH-0.5@rGO） as positive electrode, and porous nitrogen/sulfur co-doped rGO aerogel （NS-3D rGO） as negative electrode has been prepared. The NPOH-0.5@rGO electrode combines the advantages of the NPOH hollow microspheres and the conductive rGO layers giving rise to a large specific capacitance, high cycling reversibility, and excellent rate performance. The NS-3D rGO electrode with abundant porosity and active sites promotes electrolyte infiltration and broadens the working voltage range. The ASC （NPOH-0.5@rGO//NS-3D rGO） shows a maximum voltage of up to 1.4 V, outstanding cycling ability （capacitance retention of 95.5% after 10,000 cycles）, and excellent rate capability （capacitance retention of 77% as the current density is increased ten times）. The ASC can light up an light-emitting diodes （LED） for more than 20 min after charging for 20 s. The fabrication technique and device architecture can be extended to other active oxide and carbon-based materials for next-generation high-performance electrochemical storage devices.
基金supported by the National Basic Research Program of China(2013CB934103 and 2012CB933003)the International Science&Technology Cooperation Program of China(2013DFA50840)+4 种基金the National Natural Science Foundation of China(51521001 and 51272197)the National Natural Science Fund for Distinguished Young Scholars(51425204)Hubei Province Natural Science Fund for Distinguished Young Scholars(2014CFA035)the Fundamental Research Funds for the Central Universities(WUT:2015-III-0322015-III-021)
文摘本文通过调节烧结温度设计构筑了一种纳米多面体颗粒堆积的中空球状Li Ni0.5Mn1.5O4材料,并进一步通过碳纳米管(CNT)的改性来提高材料的循环性能和高倍率性能.纳米中空结构不仅减少了锂离子的扩散路径,也保证了电解液和正极材料的充分接触,三维网状CNT的改性提高了材料的电子导电率,从而明显改善了材料的循环和高倍率性能.最终得到的LNMO-850/CNT材料在5 C的电流密度下初始容量为127 m A h g-1,500次循环后容量保持在104 m A h g-1.而在20 C的高电流密度下容量仍达到121 m A h g-1,体现了材料优异的循环和高倍率性能.
