Metal Organic Framework’s Application In Li-S Battery And The Study Of Its Lithium Ion Conductivity

Metal-organic frameworks(MOFs)are a class of porous crystalline materials composed of metal ions(or clusters)linked by organic ligands.Due to their large surface areas,regular and turnable pore sizes,and tailorable chemistry,MOF materials have shown great promise for a variety of applications in adsorption,separation,catalysis,sensor,ion conductivity,energy storage areas.Lithium sulfur(Li-S)battery have attracted more attention as the candidate for next generation energy storage system due to their advantages in high energy density and theoretical capacity,but also possesses low cost,low toxicity and high natural abundance.However,there are still some crucial challenges towards the practical application of lithium-sulfur battery,such as the shuttle effect of highly soluble polysulfide intermediates,the volume expansion of sulfur in charge-discharge process and the poor electrical conductivity of sulfur and Li2S,which leads to the poor cycle and rate performances.In the first chapter,we choose UiO-66,a chemical stability and regular porous structure MOF,coated in commercial PP separator with doctor-blade method to solve the shuttle effect of soluble polysulfide in Li-S battery.Due to its regular pore sizes and strong interaction with soluble polysulfide,UiO-66 can serve as both physical and chemical barrier materials for soluble polysulfides to suppress the shuttle effect in Li-S batteries.Till now,almost study of MOF based ion conductor all focused on polycrystalline films and nanoparticle coated membranes.However,the defects and grain boundaries makes it’s difficult for us to study ion conductivity and mechanism in pristine MOF,In the second chapter,we firstly fabrated a single crystal electrochemical device with sub-cenmeter HKUST-1 crystal.Base on the device,we systematically test the Li+conductivity of pristine HKUST-1 at different temperature and investigate the potential mechanism by XRD,FTIR,ICP and other characterization techniques.This work will also draw the attention toward the development of MOF ion conductor and solid electrolyte...