Preparation And Properties Of Doped-graphene Based Anode Material For Lithium Ion Batteries

Lithium-ion batteries（LIBs）have been widely used in various portable electronic devices because of their superior performance.However,with the development of electric vehicles and energy storage market,the performance of commercial LIBs can not meet the market demand.The synthesis of graphene and metal oxide composites is a viable solution for improving the cell performance.In this paper,we combine thedoped-graphene with metal oxide as the high-performance anode material for LIBs.The results are as follows:（1）N-doped graphene/MnO₂ nanowires composites were successfully prepared by hydrothermal method using N-doped porous graphene as the matrix.This material has a specific capacity of 937.6 mAh/g at a current density of 50 mA/g when used as anode materials for LIBs.It is notable that it has excellent rate performance and cycle stability.At a current density of 1000 mA/g,a specific capacity of 312 mAh/g was retained even after 2400 cycles.（2）Graphene oxide,SnCl₂·2H₂O and TPPScomposite materials were prepared and then carbonized at high temperature.As result,we successfullyprepared the N,S-doped graphene/SnO₂ nano-spheres composite materials.The particle size of SnO₂ is about 10 nm.This material has a high specific capacity of about 860 mAh/g at a current density of 50 mA/g whenusedas anode materials for LIBs.After 100 cycles,a specific capacity of 845 mAh/g was maintained,exhibiting good cycle stability.（3）Graphene oxide was used as the carrier to composite with SnTPPS.After carbonizedunder high temperature,we successfully fabricated N,S-doped graphene/SnO₂ nano-spheres composites.Compared with physical mixing Sn2+,this method is simple,and theparticle sizeofthe obtainedSnO₂ is smaller.This material has a high specific capacity of about 860 mAh/g at a current density of 50 mA/g when tested as anode materials for LIBs.And a specific capacity of 684.6 mAh/g was maintained after 100 cycles,showing good cycle stability.