Synthesis And Properties Of Novel Conductive Conjugated Organic Compounds For Lithium Battery Energy Storage

The sharp increase in the demand for non-renewable energy has had a serious negative impact on the earth’s ecological environment,so it is urgent to study pollution-free and sustainable new energy sources.The development of clean and renewable energy such as wind energy and solar energy can reduce the dependence on traditional fossil fuels,but there are still limitations in time and space,and further research is needed to develop efficient and green energy storage devices.Among many energy storage technologies,lithium-ion batteries are widely used in daily life due to their advantages of large capacity,high operating voltage,long cycle life,high safety and fast charging and discharging speed.However,traditional commercial lithium battery materials exist problems such as high cost,low theoretical capacity and difficulty in recycling.The application of organic redox materials in lithium-ion batteries is in the ascendant,and they have the advantages of low cost,environmental friendliness,and their electrochemical properties can be regulated by molecular structure design.Among many organic electrode materials,quinone compounds/polymers have attracted attention due to their good electrochemical reversibility,multiple electron transfer reaction kinetics,environmental friendliness,and large-scale production.The polymer has low electrochemical specific capacity and cycle stability due to its easy solubility,which needs to be further developed.In this paper,we use the method of preparing organic carbonyl compounds with large conjugated planar structure to reduce the solubility of the compounds and solve the problem of battery stability caused by solubility.Electrochemically active cathode active materials quinone-based polymers/compounds were synthesized,assembled into Li-ion batteries,and their properties were investigated in detail.The main research contents are as follows:（1）A novel conjugated polymer polypyrroleanthraquinone（e-PAQPy）containing redox-active anthraquinone units was prepared by electrochemical polymerization.Its structure and physical properties were characterized.The e-PAQPy was compounded with different proportions of Ketjen Black as a lithium battery cathode material and assembled into a half-cell.The electrochemical properties of e-PAQPy in the half-cell were studied by electrochemical means.The assembled battery has a high specific capacity of 196.2 m Ah g^-1 at 0.1 C,a Coulombic efficiency of100%,and a capacity retention of 79%after 500 cycles.At the same time,the battery exhibits excellent rate performance and long-cycle stability.（2）A novel nitrogen-containing polyquinone material,hexaazatrinaphthoquinone（HATNQ）,was synthesized by chemical polymerization.The structure and physical properties of HATNQ were characterized by nuclear magnetic resonance and scanning electron microscopy（SEM）.The results showed that HATNQ was in loose granular form with more channels and larger pore volume.The theoretical capacity of the designed HATNQ reaches 515 m Ah g^-1,and its actual specific capacity at 0.1 C is 372.3 m Ah g^-1.（3）Electrochemically active 3,3,5,5-tetramethyl-4,4-dihydroxybiphenyl/ketjen black composite（TMDHB/KB）was prepared,which was used as a solid cathode,lithium sheet Assemble the half-cell for the anode.Its electrochemical performance and battery performance were studied by cyclic voltammetry（CV）,battery charge-discharge meter,etc.The results show that the TMDHB/KB cathode exhibits a higher peak potential（2.8 V）and better redox reversibility in the half-cell.The battery has a high specific capacity of 218.71 m Ah g^-1 at 0.1 C,and the capacity retention rate is 60%after 150 cycles.