Preparation And Lithium Storage Performance Of Anthraquinone-based Organic Electrode Materials

Quinone in organic electrode materials is regarded as an ideal electrode material for Lithium-ion batteries,because it has the characteristics of high theoretical capacity,various structural design,low price and environmental friendliness.However,most small quinones are plagued by high solubility in non-aqueous electrolytes,leading to rapid capacity decay and incapacity for further application.In line with these problems,two strategies including anchoring and polymerization based on the anthraquinone small molecule are formulated and implemented.These two methods directly indicate the direct relationship between molecular structure design and electrochemical performance.The research is as follows:（1）Graphene oxide（GO）and 2,6-diaminoanthraquinone（2,6AAQ）were polymerized in a solvothermal process to form an integrated 2,6AAQ/RGO composites.We investgated the electrochemical performance of the composite materials,which were polymerized with 2,6AAQ and RGO in different feeding ratios.The results show that the 2,6AAQ/RGO-3 material with the mass ratio of 2,6AAQ:RGO of 1:1.5 has an initial discharge capacity of 404.5 mA h g^-1.When the current density is maintained at 0.1 C,400 cycles of charge and discharge cycles are carried out,and the capacity retention rate reaches 91.6%.Anchoring the anthraquinone structure to the graphene skeleton can reduce the dissolution of small molecules.Such a structural design can improve the long-cycle stability of electrode materials and obtain excellent electrochemical performance.（2）1,3,5-triformaldehyde phloroglucinol（TFP）and 2,6-diaminoanthraquinone（2,6AAQ）（or 1,4-diaminoanthraquinone（1,4AAQ））was prepared by molecular polymerization to form a two-dimensional COF（2,6AAQ-TFP COF or 1,4AAQ-TFP COF）with pore sizes of about 1.6 nm and 5 nm,respectively.On the one hand,the target product can effectively inhibit the dissolution of small molecules.On the other hand,its porous structure is conducive to the infiltration of the electrolyte and promotes the reaction of lithium ions with active sites,thereby increasing the actual capacity of the active material.By test comparison,2,6AAQ-TFP COF delivers a high specific capacity(140 mA h g^-1),and the excellent long cycle stability,500 mA g^-1 can carry out 2000 cycles of charge and discharge reaction,still has 85.7%capacity retention.