Application Of [N,N’-bis（2-anthraquinone）]-perylene-3,4,9,10-tetracarboxydiimide In Lithium-ion Batteries

Currently,the cathode materials for commercial lithium-ion batteries（LIBs）are mostly inorganic materials,which have reached a bottleneck in energy density and mainly come from ores rather than renewable energy sources.The cost and environmental issues of inorganic cathodes have accelerated the demands for organic cathode materials which are both abundant on earth and conducive to sustainable development.In addition,compared with inorganic cathodes,organic cathode materials can also achieve high energy density and excellent cycling stability by designing specific structures.However,there are still many challenges in the commercialization of organic cathodes.One of the main problems is that the high solubility of small-molecule organic cathode active materials in organic electrolytes will lead to the decline of the comprehensive electrochemical performance of the batteries,especially the cycle stability.Focusing on the above problems,this work introduces the synthesis,purification and characterization of a novel small-molecule organic compound,[N,N’-bis（2-anthraquinone）]-perylene-3,4,9,10-tetracarboxydiimide,which is basically insoluble in most organic electrolytes.And[N,N’-bis（2-anthraquinone）]-perylene-3,4,9,10-tetracarboxydiimide was applied as the cathode active material in LIBs.Meantime,the effects of electrolytes,conductive additives and binders on the performance of[N,N’-bis（2-anthraquinone）]-perylene-3,4,9,10-tetracarboxydiimide Li-ion half cells were investigated.The experimental results showed that the use of ether electrolyte,Ketjen black as conductive carbon additive,and LA133 aqueous solution as binder could make[N,N’-bis（2-anthraquinone）]-perylene-3,4,9,10-tetracarboxydiimide successfully exert its electrochemical activity.And based on the electrolyte system with 1,3-dioxolane/1,2-dimethoxyethane（DOL/DME）as the solvent and lithium bis（trifluoromethanesulfonyl）-imide（Li TFSI）as the electrolyte salt,the effect of electrolyte concentration on the half cells was also studied.It was found that when the concentration of the electrolyte was 3mol/L,the comprehensive performance of the Li-ion half cells was better.In the voltage range of 3.6-1.1 V,the peak specific capacity of[N,N’-bis（2-anthraquinone）]-perylene-3,4,9,10-tetracarboxydiimide was 229 m Ah/g（the carbon blank capacity was about 35m Ah/g）,and the capacity retention rate was still greater than 82%after 3 months of cycling.Based on the performance of[N,N’-bis（2-anthraquinone）]-perylene-3,4,9,10-tetracarboxydiimide in Li-ion half cells,this work further applied the reduced state（Li₄TP）of lithium terephthalate（Li₂TP）to replace the lithium metal sheet as the anodes,and constructed all-organic lithium-ion batteries（OLIBs）with the[N,N’-bis（2-anthraquinone）]-perylene-3,4,9,10-tetracarboxydiimide cathodes.The resulting OLIBs could achieve a long lifetime of over 20,000 cycles and an energy density of 296 Wh/kg _Cathode in the voltage range of 3.2-0.2 V.