Preparation And Electrochemical Performance Study Of Graphene Based Organic Small Molecule Lithium Battery Cathode Materials

The current lithium ion batteries?LIBs?development paths explored have been energized primarily by breakthroughs in the design of new cathodes.Meanwhile,the inorganic intercalation cathode materials such as LiCoO₂,LiMn₂O₄ and LiFePO₄ in commercial LIBs are encountering their performance bottleneck in low theoretical capacities,limited mineral resources and relatively high costs.As one of the promising cathode candidates,Organic cathode materials are highly attractive owing to their high theoretical capacities,great safety,adjustable fabrication in the molecular level,and ideal sustainability.Organic molecules with appropriately designed functional groups are electroactive towards lithium ions as well as some earth-abundant metal ions.The main contents of our work are as follow.Organic cathode materials such asN,N'-bis?2-N,N-dialkylaminoethyl?-3,4,9,10-perylenebis?dicarboximides??PDI?,are highly attractive owing to their high theoretical capacities,great safety,adjustable fabrication in the molecular level,and ideal sustainability.However,problems of short cycle life and low rate capacity owing to dissolution of active materials into the electrolyte have been an inevitable obstacle to practical applications.Carbon materials such as active carbon,carbon nanotubes and graphene,cannot stabilize these organic species in electrolytes well due to their weak interactions.Here,we report a novel organic cathode design to achieve long-cycling lithium ion batteries?LIBs?,which rely on the ionic interactions between positively charged PDI and negatively charged graphene oxide?GO?.In this design,carbon matrices can load high amount of organic molecules,and they are strong enough to hold them in electrolytes for a long time.As a result,this unique design enables the fabrication of organic-LIBs?PDI-LIBs?with a remarkably high reversible capacity exceeding 81mAh/g with excellent cycleability at 25mA/g.Moreover,at a high current rate of 500mAh/g,the revisable capacity still keeps at28.4mAh/g.Further investigations confirmed that our strategy is effective for numerous other organic compounds.