As an emerging member of the two-dimensional(2D)material family,V_(2)CT_(X)MXene shows great potential in the application of lithium-ion capacitors(LICs)due to its unique structure and excellent electrical conductivit...As an emerging member of the two-dimensional(2D)material family,V_(2)CT_(X)MXene shows great potential in the application of lithium-ion capacitors(LICs)due to its unique structure and excellent electrical conductivity.However,severe nanosheets stacking and intra-layer transport barriers have limited the further development of V_(2)CT_(X)MXene-based materials.Herein,we prepared Kions and–O functional group co-modified V_(2)CT_(X)MXene(VCT-K)and further incorporated it with single-walled carbon nanotube(SWCNT),obtaining freestanding V_(2)CT_(X)composite films(VCT-K@C)with the 3D conductive network.Significantly,K+ions were introduced into V_(2)CT_(X)MXene to stabilize the interlayer structure and prevent the aggregation of nanosheets,the terminal group of–O was controllably modified on the surface of MXene to improve the Li+ions storage reversible capacities and the SWCNT acted as the bridge between MXene nanosheets to opens up the channels for ion/electron transportation in the longitudinal direction.Benefited from the synergistic effect of VCT-K and SWCNT,the VCT-K@C exhibits superior reversible specific capacities of 671.8 mA h g^(-1)at 0.1 A g^(-1)and 318 mA h g^(-1)at 1.0 A g^(-1).Furthermore,the assembled LICs with VCT-K@C anode coupling activated carbon(AC)cathode deliver an outstanding power density of 19.0 kW kg^(-1)at 67.4 Wh kg^(-1),a high energy density of 140.5 Wh kg^(-1)at 94.8 W kg^(-1)and a stable capacitance retention of 86%after 6000 cycles at 10 A g^(-1).Such unique structures and excellent electrochemical properties are expected to pave the way for the large-scale application in LICs of MXene-based materials.展开更多
锂离子电容器(LICs)是一种很有前途的储能装置,因为它们同时具有锂离子电池的高能量密度和超级电容器的高功率密度的特点.然而,由于锂离子电容器中阳极和阴极之间电化学反应动力学的不匹配使得探索具有快速离子扩散和电子转移通道的阳...锂离子电容器(LICs)是一种很有前途的储能装置,因为它们同时具有锂离子电池的高能量密度和超级电容器的高功率密度的特点.然而,由于锂离子电容器中阳极和阴极之间电化学反应动力学的不匹配使得探索具有快速离子扩散和电子转移通道的阳极材料面临挑战.在此,通过静电纺丝策略将具有可控末端基团的二维Ti_(3)C_(2)MXene引入一维碳纳米纤维中,形成三维导电网络.在这种Ti_(3)C_(2)MXene和碳基复合材料(称为KTi-400@CNFs)中,二维纳米片结构赋予了Ti_(3)C_(2)MXene更多Li+存储活性位点,而碳骨架则有利于提高复合材料的导电性.更值得一提的是,在Ti_(3)C_(2)MXene和碳骨架的界面上形成了Ti–O–C键.复合材料中的这种化学键为电子的快速传输和离子在层与层之间纵向的快速扩散建立了桥梁.因此,优化后的KTi-400@CNFs复合材料在电流密度为5 A g-1的情况下,500次循环后仍保持235 mA h g-1的良好容量.由KTi-400@CNFs//AC组成的锂离子电容器实现了高能量密度(114.3 W h kg-1)和高功率密度(12.8 kW kg-1).KTi-400@CNFs的这种独特结构和优异的电化学性能为二维材料制备提供了参考.展开更多
基金funded by the National Natural Science Foundation of China(Grant Nos.22005167 and 21905152)the Shandong Provincial Natural Science Foundation of China(Grant Nos.ZR2020QB125 and ZR2020MB045)+1 种基金the China Postdoctoral Science Foundation(Grant Nos.2021M693256,2021T140687 and 2022M713249)the Qingdao Postdoctoral Applied Research Project and the Youth Innovation Team Project for Talent Introduction and Cultivation in Universities of Shandong Province。
文摘As an emerging member of the two-dimensional(2D)material family,V_(2)CT_(X)MXene shows great potential in the application of lithium-ion capacitors(LICs)due to its unique structure and excellent electrical conductivity.However,severe nanosheets stacking and intra-layer transport barriers have limited the further development of V_(2)CT_(X)MXene-based materials.Herein,we prepared Kions and–O functional group co-modified V_(2)CT_(X)MXene(VCT-K)and further incorporated it with single-walled carbon nanotube(SWCNT),obtaining freestanding V_(2)CT_(X)composite films(VCT-K@C)with the 3D conductive network.Significantly,K+ions were introduced into V_(2)CT_(X)MXene to stabilize the interlayer structure and prevent the aggregation of nanosheets,the terminal group of–O was controllably modified on the surface of MXene to improve the Li+ions storage reversible capacities and the SWCNT acted as the bridge between MXene nanosheets to opens up the channels for ion/electron transportation in the longitudinal direction.Benefited from the synergistic effect of VCT-K and SWCNT,the VCT-K@C exhibits superior reversible specific capacities of 671.8 mA h g^(-1)at 0.1 A g^(-1)and 318 mA h g^(-1)at 1.0 A g^(-1).Furthermore,the assembled LICs with VCT-K@C anode coupling activated carbon(AC)cathode deliver an outstanding power density of 19.0 kW kg^(-1)at 67.4 Wh kg^(-1),a high energy density of 140.5 Wh kg^(-1)at 94.8 W kg^(-1)and a stable capacitance retention of 86%after 6000 cycles at 10 A g^(-1).Such unique structures and excellent electrochemical properties are expected to pave the way for the large-scale application in LICs of MXene-based materials.
基金supported by the National Natural Science Foundation of China (22005167 and 21905152)Shandong Provincial Natural Science Foundation (ZR2020QB125 and ZR2020MB045)+2 种基金China Postdoctoral Science Foundation (2021M693256, 2021T140687 and 2022M713249)Qingdao Postdoctoral Applied Research Project, Taishan Scholar Project of Shandong Province (ts20190937)the Youth Innovation Team Project for Talent Introduction and Cultivation in Universities of Shandong Province。
文摘锂离子电容器(LICs)是一种很有前途的储能装置,因为它们同时具有锂离子电池的高能量密度和超级电容器的高功率密度的特点.然而,由于锂离子电容器中阳极和阴极之间电化学反应动力学的不匹配使得探索具有快速离子扩散和电子转移通道的阳极材料面临挑战.在此,通过静电纺丝策略将具有可控末端基团的二维Ti_(3)C_(2)MXene引入一维碳纳米纤维中,形成三维导电网络.在这种Ti_(3)C_(2)MXene和碳基复合材料(称为KTi-400@CNFs)中,二维纳米片结构赋予了Ti_(3)C_(2)MXene更多Li+存储活性位点,而碳骨架则有利于提高复合材料的导电性.更值得一提的是,在Ti_(3)C_(2)MXene和碳骨架的界面上形成了Ti–O–C键.复合材料中的这种化学键为电子的快速传输和离子在层与层之间纵向的快速扩散建立了桥梁.因此,优化后的KTi-400@CNFs复合材料在电流密度为5 A g-1的情况下,500次循环后仍保持235 mA h g-1的良好容量.由KTi-400@CNFs//AC组成的锂离子电容器实现了高能量密度(114.3 W h kg-1)和高功率密度(12.8 kW kg-1).KTi-400@CNFs的这种独特结构和优异的电化学性能为二维材料制备提供了参考.
