Research On The Synthesis And Properties Of FeS₂ And MgMnSiO₄ As New Cathode Materials For Rechargeable Magnesium Battery

Rechargeable magnesium batteries（RMBs）which using pure Mg or Mg alloy as anode and some materials allowed Mg²⁺to insert/extract as cathode,they have many good advantages,such as high energy density,environmentally friendly,low cost and safety of handling,so they are very promising to be used as new clean energy sources,portable power sources and heavy load energy devices.However,so far there is no suitable cathode materials for RMBs because of the high charge density,strong polarization effect and very slow insertion/extraction speed of Mg²⁺,so the application and development of RMBs are very slow.Recently,the reports about the cathode materials of RMBs increase significantly.The research and development of cathode materials are a hot topic in RMBs field.In this paper,the transition metal sulfide and polyanionic compounds as the cathode materials for RMBs were studied,and the electrochemical properties of cathode materials were improved by blending and structure regulation.（1）FeS₂/rGO and FeS₂/MWCNTs composites were prepared by in-situ blending of FeS₂ with carbon materials（graphene and multi-walled carbon nanotubes）by simple hydrothermal method.The hydrothermal reaction process can reduce the graphene oxide to the reduced graphene oxide.The composition and microstructures of FeS₂,FeS₂/rGO and FeS₂/MWCNTs were characterized in detail by XRD,TEM,SEM,XPS and Raman.The results show that FeS₂/rGO and FeS₂/MWCNTs composites have been successfully prepared in the experiment.The particles of pure FeS₂ are larger and agglomerate,and the size of FeS₂ particles in the composites is relatively small and uniformly distributed in surface of rGO and MWCNTs.The electrochemical test results show that the FeS₂/rGO and FeS₂/MWCNTs have higher electrochemical performance than FeS₂.Especially,FeS₂/MWCNTs composite exhibits excellent rate capability and cycle stability as cathode material for rechargeable magnesium battery.（2）MgMnSi O₄ with mesoporous structure was prepared by hydrothermal method using mesoporous Si O₂ as template.The composition and structure of material were characterized by XRD,SEM.The results show that the particle size of MgMnSiO₄ was 180 nm²50 nm with mesoporous structure.The electrochemical test results show that its electrochemical performance is inferior as cathode material for rechargeable magnesium battery.But the magnesium ion can be reversibly insertion/deintercalated in this material,and this experiment can provide reference for future research.