Fabrication And Electrochemical Application Of The Metal-organic Framework Containing Two Central Ions

As an efficient energy storage device,supercapacitor stores electrical energy by its unique struc-ture which can associate the advantages of traditional capacitor and chemical battery.It's superca-pacitor's excellent cycling stability,high power density and good rate capability that make the de-vice occupying an important position in energy storage field.Supercapacitor is a proper choice when a fast,intense or repeated charging/discharging demand is needed.As a result,supercapacitor may become a key device in new energy field that it helps to adjust electricity especially during peak and trough period of electricity generation and then makes electricity to transport in power grid smoothly in the future.Metal-Organic Framework,or MOF for short,is an advanced material in supercapacitor re-search.Its morphology is controllable and may be identical in size theoretically.MOF has obvious pseudocapacitive phenomenon because regular gaps among its particles are beneficial to make elec-trolyte ions reach to active sites faster.This characteristic increases its capacitive in fact.However,MOF needs a collector to assist electricity collecting when it is put into use on supercapacitor be-cause its poorly conductivity.Reduced graphene oxide is another hot material.Compared with MOF,it is a complementary choice which not only has good conductivity but also can help device forming free-standing structure.Therefore,this thesis has integrated reduced graphene oxide and MOF for construct a useful and powerful supercapacitor.Concisely,its main content is as follows:1.Introduced supercapacitor briefly from its energy storage theory,several categories of its materials,how to evaluate its performance and methods for analyse ingredient in it;2.Fabricated reduced graphene oxide and the MOF which uses Co²⁺and Fe²⁺as its central ions,then integrated these two materials for construct an electrode.The electrode has performed good rate capability and cycling stability in electrochemical test.Its capacitance contained 72.6%at the current density of 10 mA/cm² compared with at 1 mA/cm² while the capacitance reached 106%of1^st cycle's when the device had experienced 10000 charge/discharge procedures.Besides,the best reaction condition of the MOF's fabricating is explored;3.Furthermore,Mn²⁺is chosen to replace Fe²⁺in MOF for increasing device's rate capability,and then a new MOF which uses Mn²⁺and Co²⁺as its central ions is fabricated.Afterwards,the MOF is integrated with reduced graphene oxide for construct a supercapacitor.The supercapacitor has performed good cycling stability in electrochemical test,too.And its rate capability is even higher than previous electrode's.Concretely,its capacitance contained 89.4%at the current density of 10 mA/cm² compared with at 1 mA/cm² while the capacitance reached 104%of 1^st cycle's after10000 charge/discharge procedures.As same as above,the best reaction condition of the MOF's fabricating is probed at the same time;4.Sum up the electrical performance of the two electrodes in this work,and predicted their future based on some up-to-date researches.