The Electric Properities Of 2D Conducting MOF Crystalline And Porous Thin Film

Metal organic frameworks（MOFs）as a new fascinating porous solid material self-assembed by organic ligand and metal ions,possess high surface area,fine-tunable size,shape of nanoscale cavities,chemical functionality of internal surface which have drawn considerable attention in recent two decades.MOFs have been widely applied in a myriad of fields,gas storage and separation,catalysis,sensors,electricity,photology,magnetics.With the ever-growing urgent need of energy storage devices for small portable electronics,flexible and wearable electronics,vehicle electrification and large-scale smart grid stationary storage systems,all sorts of storage systems with reliable electrochemical performance have been evolved.In recent years,Supercapacitors and Lithum-Sulfur batteries have attracted widly attentions because of their hign energy density.Considering that MOFs have the fine-tunable size,shape of nanoscale cavities and chemical functionality of internal surface,exploring the electrochemical performances of MOFs materials is a hot topic.In this paper,we develop our works based on a 2D conducting metal-organic framework named Ni₃（HITP）₂,which has a structure similar to graphene.The works in detail as following:In the second chapter,the Ni₃（HITP）₂ film was loaded on carbon paper in situ.Then the carbon paper loaded by Ni₃（HITP）₂ film was acted as the electrode,further to test the electrochemical performance under the water system.From the HRSEM,we can see the Ni₃（HITP）₂ film loaded on the carbon paper with a nanowire structure.The reasults about the electrochemical performance suggest that the supercapacitor with the Ni₃（HITP）₂ film-carbon paper electrode has a typical double layer capacitance.And the capacitance is about 156 F g^-1,what’s more,it shows a good recycle performance,the capacitance retained abou 84.7% after 500 recycles.In the third chapter,the Ni₃（HITP）₂ film was used as the functional layer of the separator for Li-S battery.We first use a “gas-liquid” in situ method to load Ni₃（HITP）₂ on the commerical PP membrane,and get a Ni₃（HITP）₂-separator.This is the first successful attempt to introduce a MOF material as the functional layer of the separator for Li-S battery without any other binder and conductive agent.The HRSEM suggests that the uniform and compaction coating was obtained.Due to the high conducting and the pore size about 1.4 nm of Ni₃（HITP）₂,the Ni₃（HITP）₂-separator not only can provide an effective diffusion path for Li+,but also inhibited the “shuttle-effect”,further to increase the use ratio of active sulfur.Even though the Ni₃（HITP）₂ loading is just about 0.066 mg cm^-2,the thickness is only about 480 nm（which roughly lighter and thinner than other separator reported）,the performance also suggests a high capacitance,an excellent recycle performance and a good rate capability.When the sufur loading is about 3.5 mg cm^-2,the capacity is as high as 1244 mAh g^-1.Besides,the discharge capacity is 716 mAh g^-1 under 1 C,during 500 cycles,the capacity retention rate is 84.1%,the recycle performance was increased and the coulombic efficiency is as high as 98%.In addition,the sulfur loading was increased to 8.0 mg cm^-2,it still shows a good electrchemical performance.