在乙醇胺和水组成的混合溶剂中,Mn(Ac)_2与氧化石墨烯一步反应得到还原石墨烯(RGO)与黑锰矿纳米颗粒(Mn_3O_4)组成的复合材料Mn_3O_4@RGO。以Mn_3O_4@RGO为正极,RGO为负极,组装得到了具有优良储能性能的非对称型超级电容器Mn_3O_4@RGO//...在乙醇胺和水组成的混合溶剂中,Mn(Ac)_2与氧化石墨烯一步反应得到还原石墨烯(RGO)与黑锰矿纳米颗粒(Mn_3O_4)组成的复合材料Mn_3O_4@RGO。以Mn_3O_4@RGO为正极,RGO为负极,组装得到了具有优良储能性能的非对称型超级电容器Mn_3O_4@RGO//RGO。基于活性物质的总质量,电容器的最大能量密度可达21.7 Wh/kg,相应的功率密度为0.5 k W/kg;同时,最大功率密度为8 k W/kg时,对应的能量密度为11.1 Wh/kg。Mn_3O_4@RGO//RGO还表现出良好的循环稳定性,在经历5000次循环后,比电容依然保持88.4%。电容器的良好储能性能可归因于在RGO表面生长的高密度Mn_3O_4纳米颗粒和RGO的良好导电性能。展开更多
The hierarchical ZnMn2O4/Mn3O4 composite sub-microrods were synthesized via a water-in-oil microemulsion method followed by calcination.The ZnMn2O4/Mn3O4 electrode displays an intriguing capacity increasing from 440 t...The hierarchical ZnMn2O4/Mn3O4 composite sub-microrods were synthesized via a water-in-oil microemulsion method followed by calcination.The ZnMn2O4/Mn3O4 electrode displays an intriguing capacity increasing from 440 to 910 mA·h/g at 500 mA/g during 550 consecutive discharge/charge cycles,and delivers an ultrahigh capacity of 1276 mA·h/g at 100 mA/g,which is much greater than the theoretical capacity of either ZnMn2O4 or Mn3O4 electrode.To investigate the underlying mechanism of this phenomenon,cyclic voltammetry and differential capacity analysis were applied,both of which reveal the emergence and the growth of new reversible redox reactions upon charge/discharge cycling.The new reversible conversions are probably the results of an activation process of the electrode material during the cycling process,leading to the climbing charge storage.However,the capacity exceeding the theoretical value indicates that there are still other factors contributing to the increasing capacity.展开更多
文摘在乙醇胺和水组成的混合溶剂中,Mn(Ac)_2与氧化石墨烯一步反应得到还原石墨烯(RGO)与黑锰矿纳米颗粒(Mn_3O_4)组成的复合材料Mn_3O_4@RGO。以Mn_3O_4@RGO为正极,RGO为负极,组装得到了具有优良储能性能的非对称型超级电容器Mn_3O_4@RGO//RGO。基于活性物质的总质量,电容器的最大能量密度可达21.7 Wh/kg,相应的功率密度为0.5 k W/kg;同时,最大功率密度为8 k W/kg时,对应的能量密度为11.1 Wh/kg。Mn_3O_4@RGO//RGO还表现出良好的循环稳定性,在经历5000次循环后,比电容依然保持88.4%。电容器的良好储能性能可归因于在RGO表面生长的高密度Mn_3O_4纳米颗粒和RGO的良好导电性能。
基金Ting-ting FENG acknowledges the financial support from Professor Paul V.BRAUN at Department of Materials Science and Engineering,University of Illinois at Urbana-Champaign,the support from Chinese Scholarship Council during her visit to University of Illinois at Urbana-Champaign,partial financial supports from Department of Science and Technology of Sichuan Province,China(2019YFH0002,2019YFG0222 and 2019YFG0526).The research was partly carried out in the Frederick Seitz Materials Research Laboratory Central Research Facilities,University of Illinois at Urbana-Champaign.
文摘The hierarchical ZnMn2O4/Mn3O4 composite sub-microrods were synthesized via a water-in-oil microemulsion method followed by calcination.The ZnMn2O4/Mn3O4 electrode displays an intriguing capacity increasing from 440 to 910 mA·h/g at 500 mA/g during 550 consecutive discharge/charge cycles,and delivers an ultrahigh capacity of 1276 mA·h/g at 100 mA/g,which is much greater than the theoretical capacity of either ZnMn2O4 or Mn3O4 electrode.To investigate the underlying mechanism of this phenomenon,cyclic voltammetry and differential capacity analysis were applied,both of which reveal the emergence and the growth of new reversible redox reactions upon charge/discharge cycling.The new reversible conversions are probably the results of an activation process of the electrode material during the cycling process,leading to the climbing charge storage.However,the capacity exceeding the theoretical value indicates that there are still other factors contributing to the increasing capacity.
