Synthesis Of Indole-based Conjugated Microporous Polymers And Their Performance As Anode Materials

As an important component of lithium-ion batteries,anode is one of the key factors to improve the performance of lithium-ion batteries.Therefore,it is very important to develop a kind of anode material of lithium-ion batteries with high capacity and stable cycle performance at high current density.In recent years,organic polymers with redox activity as anode active materials for lithium ion batteries are becoming a research hotspot in this field.Compared with inorganic metal oxide electrodes,organic electrodes have the advantages of low cost,recyclability,and environmental friendliness.On the other hand,indole has been widely applied in the design and synthesis of photoelectric materials due to its unique redox activity and structural characteristics.In this paper,the synthesis and characterization of indole-based conjugated microporous polymers and their application as lithium-ion battery anodes are mainly discussed,and the lithium storage mechanism of the prepared anode materials was investigated through theoretical calculation.The thesis includes the following three parts:?1?In chapter 3,a phenolic resin indole crosslinked polymer?IPCP?was prepared by sol-gel method.The IPCP can be used as an anode material of lithium ion battery and exhibited high capacity(501 mA h g^-1,50 mA g^-1),stable cycle life?600 cycles?.In this chapter,the application of indole-based porous polymers in lithium-ion battery anode materials was explored for the first time,which provided valuable strategies for the application of indole-based polymers in lithium-ion batteries.?2?Inchapter4,anindole-basedconjugatedmicroporouspolymer,poly-?bisindolylmaleimide??PBIM?,with superior electrochemical performance as an anode material for LIBs was successfully synthesized by FeCl₃-promoted oxidative coupling polymerization.Owing to its inherent microporous structure,typical D-?-A conjugated system and abundant nitrogen-containing structure,it exhibited high capacity(1172 mA h g^-1,50 mA g^-1),outstanding cycle life?1000 cycles?,and remarkable rate performance(214 mA h g^-1,2.5C)as an anode active material for lithium ion batteries.?3?In chapter 5,we designed and synthesized a planar triazatruxene molecule with large?-conjugated structure.The crosslinked poly?triazatruxene??PTAT?was successfully prepared by oxidative coupling polymerization.A wider range of intermolecular channel was caused by cation-?interaction inducing lithium ion insert into polymer network,thereby effectively prevented the detrimental effect from?-?stacking interaction.On the other hand,the cation-??Li⁺-??interaction could enable a number of lithium ions to concentrate around the polymer chain,giving rise to shorten the diffusion pathway of lithium ions,which made the prepared electrode material had high capacity(892 mAh g^-1,100 mA g^-1),excellent rate performance(200 mAh g^-1,4C),and outstanding cycle life?500 cycles?.This chapter synthesized a new type of organic anode material through molecular structure design,which had potential significance for the practical application of organic lithium ion batteries.