Synthesis And Electrochemical Performance Study Of Metal-Organic-Frameworks 1D Derivatives

Electrode materials have animportant influence on the performance of the battery.At present,lithium ion batteries composed of graphite negative electrode and lithium cobaltate positive electrode are difficult to meet the social requirements of high energy/power density,and it is urgent to find new electrode materials.Based on this,a series of electrode materials were prepared by combine metal organic framework with electrospinning method.?1?Cobalt sulfide coupled with carbon materials attracted tremendous interest as promising candidates for high performance energy storage equipment.In this work,hollow Co₃S₄/C nanoparticles?NPs?with a uniform size of 30 nm homogeneously anchored on nitrogen-doped carbon nanofibers?denoted as Co₃S₄/CNF?were prepared by electrospinning method,followed by carbonization and sulfuration process.As a result, the free-standing Co₃S₄/CNF-4 composites demonstrated a high reversible capacity of 742 mA h·g^-1 at 200 mA·g^-1 after 200 cycles and 436 mA h·g^-1 at 1 A·g^-1 after 500 cycles for lithium ion battery and excellent electrochemical performance for sodium ion batteries (initial discharge capacity of 610 mA h·g^-1 and maintained the reversible capacity of 304 mA h·g^-1 at 200 mA·g^-1 after 200 cycles).Such superior electrochemical performance of the Co₃S₄/CNF-4 composites can be ascribed to the interconnected 3D conductive network,hollow structure and synergetic effect of component.?2?Porous carbon nanofiber acted as host of sulfur cathode in lithium-sulfur?Li-S?battery can effectively moderate the shuttling effect of lithium polysulfides,improve electronic conductivity,and accommodates the associated volume expansion of sulfur during cycling. However,the capacity decay caused by polysulfide shuttling still remains a great challenge due to the weak physical interaction between the lithium sulfides and carbon host.In this work,we prepared sulfur and nitrogen dually doped porous carbon nanofiber ?denoted as SN-PCNF?served as host materials for sulfur.The doping of sulfur atom and nitrogen atom greatly enhances the chemisorption of lithium polysulfides.The combination of physical fixation and chemisorption effectively suppresses the shuttle effect of lithium polysulfide.In addition,the high specific surface area of SN-PCNF can well alleviate the volume change of sulfur during charge and discharge.Benefiting from the above advantages,the SN-PCNF@S electrode delivereda high initial discharge capacity of 1133 mA h·g^-1 at 0.1 C,and maintained the reversible capacity of 554 mA h·g^-1 after 150 cycles.And more importantly,the SN-PCNF@S cathode demonstrated a reversible capacity of 330 mA h·g^-1after 500 cycles at 0.5 C.