Research On The Synthesis And Electrochemical Properties Of Rechargeable Magnesium Battery Cathode Materials

Magnesium batteries may be a candidate of high energy density batteries comparable with lithium batteries due to cheaper raw material costs and less danger of magnesium than lithium. Researches about rechargeable magnesium batteries focus on non-aqueous electrolyte systems, from which magnesium can be reversibly deposited and dissolved, and cathode materials that can reversibly intercalate and de-intercalate magnesium ions.In this work, we have prepared novel cathode materials MgxMySiO(4M=Fe,Ni,x+y=2) for rechargeable magnesium battery by high temperature solid-state reaction and molten salt method. The heating temperature (800℃, 900℃and 1000℃), ratio of molten salt (KCl: MgO= 2:1, 4:1, 6:1 and 8:1) as well as binders (PVDF, PTFE and SBR) on the material structure, morphlogy and electrochemical performance have been studied detailedly. Moreover, Mg0.75Mn0.15Fe1.1SiO4 was prepared by doping Mn into MgFeSiO4 using the molten salt method and electrochemical performance was further studied.Electrochemical performance of the materials was tested via CR2016 coin cells with magnesium ribbon counter electrode, 0.25 mol/L Mg(AlCl2EtBu)2/THF electrolyte. At a rate of C/10, the cathode material prepared under the temperature of 900℃,and at the ratio of molten salt at 4:1 exhibited good electrochemical performance due to fine crystallite structure and small size. Moreover, the electrode using PVDF as binder had good cycling stability due to the wide expansion thickness.