A facile in situ hydrothermal route is adopted for the synthesis of NiFe_(2)O_(4)–reduced graphene oxide(NiFe_(2)O_(4)–rGO)which is verified as a promising high-property anode material for Li-ion batteries.The forma...A facile in situ hydrothermal route is adopted for the synthesis of NiFe_(2)O_(4)–reduced graphene oxide(NiFe_(2)O_(4)–rGO)which is verified as a promising high-property anode material for Li-ion batteries.The formation of NiFe_(2)O_(4) and the reduction of GO occur simultaneously.Ultrafine NiFe_(2)O_(4) nanocrystals(below 10 nm)disperse uniformly and are immobilized by the reduced graphene oxide.The electrochemical tests show that NiFe_(2)O_(4)–rGO exhibits a high specific capacity of 1129 mA h g^(−1) at 0.2 A g^(−1) after~300 discharge–charge cycles.The excellent electrochemical properties are mainly ascribed to the introduction of the graphene matrix which offers two-dimensional conductive networks for fast electron transfer and buffers the stress from volume expansion during charge–discharge cycles.Moreover,the NiFe_(2)O_(4) nanocrystals as the spacers inhibit the aggregation of rGO and form the stacking pore.More importantly,the well-designed heterostructures and the synergistic effects between NiFe_(2)O_(4) and rGO can enhance the transport of Li+and electrons and improve the structural stability of the anode,thereby enhancing the electrochemical properties.Our work not only provides an attractive strategy for the design of a hierarchical composite,but also offers a strategy for a promising anode material.展开更多
In this work,a composite of 3D network nitrogen-doped porous carbon on reduced graphene oxide(denoted as NPC/rGO)was derived from pyrolysis of zeolitic imidazolate framework-8 and graphene oxide.The as-prepared NPC/rG...In this work,a composite of 3D network nitrogen-doped porous carbon on reduced graphene oxide(denoted as NPC/rGO)was derived from pyrolysis of zeolitic imidazolate framework-8 and graphene oxide.The as-prepared NPC/rGO possesses high specific surface area,nitrogen doping and mesopores.When evaluated as the cathode catalyst for Li–O_(2)batteries,NPC/rGO exhibited higher specific capacity,better cyclability,and greater rate capability than either nitrogen doped porous carbon or reduced graphene oxide.The outstanding performances suggest that zeolitic imidazolate framework derived nitrogen doped porous carbon materials are promising for Li–O_(2)batteries.展开更多
基金supported by the National Natural Science Foundation of China(No.11774027 and 51132002).
文摘A facile in situ hydrothermal route is adopted for the synthesis of NiFe_(2)O_(4)–reduced graphene oxide(NiFe_(2)O_(4)–rGO)which is verified as a promising high-property anode material for Li-ion batteries.The formation of NiFe_(2)O_(4) and the reduction of GO occur simultaneously.Ultrafine NiFe_(2)O_(4) nanocrystals(below 10 nm)disperse uniformly and are immobilized by the reduced graphene oxide.The electrochemical tests show that NiFe_(2)O_(4)–rGO exhibits a high specific capacity of 1129 mA h g^(−1) at 0.2 A g^(−1) after~300 discharge–charge cycles.The excellent electrochemical properties are mainly ascribed to the introduction of the graphene matrix which offers two-dimensional conductive networks for fast electron transfer and buffers the stress from volume expansion during charge–discharge cycles.Moreover,the NiFe_(2)O_(4) nanocrystals as the spacers inhibit the aggregation of rGO and form the stacking pore.More importantly,the well-designed heterostructures and the synergistic effects between NiFe_(2)O_(4) and rGO can enhance the transport of Li+and electrons and improve the structural stability of the anode,thereby enhancing the electrochemical properties.Our work not only provides an attractive strategy for the design of a hierarchical composite,but also offers a strategy for a promising anode material.
基金supported by NSFC(21421001)the Tianjin Municipal Science and Technology Commission(16PTSYJC00010 and 17JCQNJC06400)the Open Funding of the State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology,Zhejiang University of Technology(GCTKF2014001)in China.
文摘In this work,a composite of 3D network nitrogen-doped porous carbon on reduced graphene oxide(denoted as NPC/rGO)was derived from pyrolysis of zeolitic imidazolate framework-8 and graphene oxide.The as-prepared NPC/rGO possesses high specific surface area,nitrogen doping and mesopores.When evaluated as the cathode catalyst for Li–O_(2)batteries,NPC/rGO exhibited higher specific capacity,better cyclability,and greater rate capability than either nitrogen doped porous carbon or reduced graphene oxide.The outstanding performances suggest that zeolitic imidazolate framework derived nitrogen doped porous carbon materials are promising for Li–O_(2)batteries.
