Synthesis Of Rare Earth Doped Fluorides And Their Electrochemical Properties

Lithium ion batteries (LIBs) have undergone intensive scientific research and rechargeable lithium-ion batteries with high energy density and potential have been shown successful commercial applications in a variety of portable electronic devices, hybrid electric vehicles, and energy storage for renewable energy sources.Transition metal fluorides have been extensively investigated for a large multielectron redox capacity through reversible electrochemical conversion reactions and can be used as alternative positive electrode materials for LiBs owing to the high operating voltages caused by their ionic character.In this dissertation, NH4FeF4nanoparticles were prepared by electrospinning and fluorination. FeF2/C nanocomposite prepared by high temperature calcination. Besides, different rare earth elements doped FeF2/C nanocomposite were prepared by the same mathod. The samples were characterized by XRD, TG—DSC, SEM, and charge-discharge properties analysis. The results showed that the diameter of NH4FeF4nanoparticles was about200-300nm, at low current density, the initial discharge capacity of about135.7mAh·g-1. The diameter of FeF2/C nanocomposite was about50nm and rare earth elements doped nanocomposite was about100nm.Although, all the nanocomposites have the same monoclinic structure,but the electrochemical performance tests show that Y-doped nanocomposite has lower initial discharge specific capacity and the influence of Ho-doped for performance is not obvious.