Study On Donor-acceptor Polymers Containing Thiophene Units As Electrode Materials For Lithium-Ion Battery

The development and effective use of energy are inseparable from the development of energy storage technology,and secondary batteries represented by lithium-ion batteries have emerged.The donor-acceptor polymer electrode material can achieve precise control of the structure by adjusting the donor-acceptor unit,which has attracted wide attention from researchers.However,How to effectively solve the problem of low conductivity and solubility of polymer electrodes is still a bottleneck in the development of lithium polymer batteries.Based on the comprehensive consideration of the above problems,this paper successfully prepared a composite material of thienyl donor-acceptor polymer deposited on carbon powder and used as a lithium ion battery electrode with excellent electrochemical performance.Preparation and research of donor-acceptor polymer composite carbon powder electrode materials containing thiophene units.Through the Stille coupling reaction,a thiophene derivative donor unit and an aromatic derivative acceptor unit containing a C=N bond are combined to synthesize a D-A monomer.The monomer and carbon powder are doped and polymerized to make a composite material.The energy band gap of the polymer decreases with the enhancement of the electronic interaction between the donor and acceptor units.The band gaps of PPTQ,PPETQ,PMFTTP,PMFMOTTP,PEBTE and PEBSe E are 1.66 e V,1.55 e V,1.39 e V,1.28 e V,1.25 e V and 0.90 e V,respectively.The polymer and carbon powder composite electrode can maintain a specific capacities of 298.7 m Ah/g,345.4 m Ah/g,369.2 m Ah/g,605.7 m Ah/g 553.3m Ah/g and 683.1 m Ah/g after being cycled for 300 cycles at a current density of 0.1A/g.Preparation and research of composite graphene electrode material based on phenolic resin Containing thiophene units.A low-bandgap phenolic resin was synthesized by a two-step method of prepolymerization and high temperature hydrothermal.The resin has high conductivity and good thermal stability.It can maintain a specific capacity of 270.9m Ah/g after 300 cycles at a current density of 100 m A/g.The prepared phenolic resin was used as a precursor for high-temperature carbonization,and the specific surface area and conductive chemical properties of the resin are significantly improved after carbonization.The resin carbonized at 700 ℃ has the most excellent electrochemical performance,and can maintain a specific capacity of 605.1 m Ah/g after being cycled for 300 cycles at a current density of 100 m A/g.Graphene was used as an additive to prepare a composite material of graphene and phenolic resin-based hard carbon.Graphene provides a good conductive network and protective layer for the resin material.The composite material can maintain a specific capacity of 462.5 m Ah/g after being cycled for 300 cycles at a current density of 100 mA/g.