Study On Electrochemical Energy Storage Of CPs-derived Carbon-Based Composites

Coordination polymers(CPs)are a class of solid materials formed by self-assembly junctions of metal ions(clusters)and organic ligands,in which organometallic framework compounds(MOFs)are classified as a subclass of CPs with potential voids and permanent porosity.These crystal materials have novel morphology diversity and topology in network geometry,and can achieve precise control of structure and function,so they can be used as precursors.The derived materials not only inherit the advantages of CPs or MOFs with large specific surface area and adjustable pore size,but also have excellent properties in supercapacitors and electrocatalysis.Nevertheless,the types and structures of CPs or MOFs are diverse,so the design of a CPs or MOFs with an ideal topology for the synthesis of derivatives with excellent properties remains a challenge.The main contents of this thesis are as follows:1.In this work,The Mn-CP([Mn₂(SO₄)₂(H₂O)₃(bibp)₂]_?)was prepared by solvent diffusion method using MnSO₄·H₂O and 4,4-diimidazole biphenyls(bibp).A series of MnS@C composites were successfully prepared at different temperatures using Mn-CP as the precursor and in situ vulcanization process,which provided an atomic economic strategy for the synthesis of sulfides and explored the effect of temperature on the properties of derived materials.Interestingly,the?-MnS@C-700 exhibits the best electrochemical capacitive performance with ultra-high BET(66 m²g^-1).The electrode has a capacitance value of up to 856 F g^-1at a current density of 0.5 A g^-1.Moreover,the energy density of asymmetric supercapacitor cells?-MnS@C-700 assembled with activated carbon can reach28.4 wh kg^-1,and the power density is 395 w kg^-1,which shows excellent long-term cycling stability and can be used as electrode materials for supercapacitors.Furthmore,four tandem ASC devices can brightly glow a lamp bulb for 30 seconds,so the?-MnS@C composite shows great applications in supercapacitors.2.In this work,we first synthesized respectively with one dimension chain and two-dimensional layer structure of coordination polymer Cu-CP-1({[Cu^I(bib)]·(NO₃)}_?)and Cu-CP-2({[Cu^II(ipa)(H₂O)]·(H₂O)₂}_?),and then the Cu-CP-1 and Cu-CP-2 were mixed and assembled to obtain a case of coordination polymer Cu-CP-3({[Cu^I(bib)]·[(Cu^II)₂(OH)(ipa)₂]}_?)with three-dimensional structure.In these three coordination polymers,the copper ions exhibit different valence states,which are+1,+2and+1&+2.Then,using them as precursors,Cu-based derivatives(labeled Cu₂O@C?CuO@C and Cu₂O/CuO@C)were prepared by microwave heating method.Through experiments,it is found that the best catalytic activity Cu₂O/CuO@C in these three materials is mainly attributed to the fact that Cu₂O/CuO@C heterostructures provide more interfacial active sites,and the interaction between the two phases promotes effective electron transfer.In addition,carbon materials provide high conductivity.with 21 mV onset potential and 53 mV low overpotential at 10 m A cm^-2current density.Hence,Cu₂O/CuO@C catalysts exhibit excellent electrocatalytic hydrogen evolution activity and stability.