Preparation Of Two-dimensional Materials And Their Application In Lithium-ion Battery

Two-dimensional（2D）materials have shown great application potential in energy conversion and storage,sensors,catalysis and many other fields owing to its unique and remarkable physical and chemical properties,while the lack of effective fabrication methods would limit the further development and practical applications of2D materials.Researchers have reported multiple preparation methods,however,these methods are usually complex,costly and inefficient.Therefore,we provided two facile and effective 2D materials fabrication methods:one for the reduction of graphene oxide（GO）and the other for the preparation of 2D metal oxides.We applied the reduced GO（RGO）and chromic oxide nanosheets in lithium-ion（Li-ion）batteries and investiaged their electrochemical performances.RGO is widely used in Li-ion batteries as the conductive filler or structure support.However,the common reduction methods need hydrazine and dangerous reducing agents or inert gas conditions and high temperature.Accordingly,we provided a novel electrochemical method to reduce GO by using the reducing environment in Li-ion batteries during the lithiation process and applied this reduction method in the fabrication of graphene based composite electrodes.The results proved that the GO based composite electrodes without any extra reducing treatment could also work well.Our electrochemical reducing method is simple and effective,and could simplify graphene based composite electrodes fabrication process.Most of the metal oxides cannot be produced by exfoliation methods due to their nonlayered crystal structure.Chemical synthesis methods are not conducive to industrialization because of their strict reaction conditions and low yield.Herein,we reported a facile method to produce 2D oxides by rapid thermal annealing of hydrous chloride precursors.This is a facile,costly and general strategy to produce metal oxide nanosheets in a large scale.We successfully obtained ultrathin Cr₂O₃,Al₂O₃,ZrO₂ and Y₂O₃ nanosheets.And we evaluated prepared Cr₂O₃ nanosheets in Li-ion batteries.The2D Cr₂O₃ electrodes showed high capacity and stable electrochemical performance,which maintained the high capacity of 986 mAh/g after 297 cycles.This result demonstrated the application potential of 2D materials in energy storage filed.