The Synthesis And Electrochemical Properties Of Sulfide&Chevrel Phases As Rechargeable Magnesium Battery Cathode Materials

With the arrival of the era of energy, it is more and more urgentdemand for the development of high energy density rechargeable batteries,which makes finding the urgent need to become environmentally friendlyand resource-rich electrode materials. The production of rechargeablebatteries is a lithium-ion battery-based, but its price and securityrequirements are not met. The principle of rechargeable magnesium issimilar to lithium-ion batteries, its price is lower （about1/24of thelithium）, environment-friendly, and has high melting point （649℃）, easyprocessing, higher security, higher capacity （2205mAh·g-1）. Rechargeablemagnesium batteries don`t have obvious advantages in a small loaddevice, but it has potential advantages for large loads （such as electricvehicles）. Magnesium ion battery is a chemical power of a good prospect.The the domestic rechargeable magnesium battery work is still at anearly stage, mainly focused on its cathode materials. This papersystematically studied the disulfide and Chevrel phase, researched onthier structure and electrochemical properties as cathode materials. Themain contents are as follows:（1） Study the sulfide as rechargeable magnesium battery cathodematerials. Give the report of the structural analysis and electrochemical characterization of sulfide modified by ball milling, organics coated andcationic replace. After milling, the specific discharge capacity is increasedand its cycling performance is better. By DMcT organic coated, the firstdischarge capacity is increased, but the cycling performance is poor. TheLa element replacement Fe in sulfide lattice, the first discharge capacityis higher while the cycling performance is poor.（2） Study the Chevrel phase compounds as cathode material forrechargeable magnesium batteries. Give the report of the structuralanalysis and electrochemical characterization of Chevrel phases whosecations are different. The average discharge specific capacity ofCu₂Mo₆S₈is high （95mAh/g）, cycling stability and reversibility.Fe_1.3Mo₆S₈after100cycles still maintain its capacity （50-55mAh/g） andthe cycle efficiency is maintained over90%. Ni_1.38Mo₆S₈as cathodematerial needs a long time activation, hardly to reach a steady state. Thecharge-discharge efficiency of the material is unstable at the same time.Fe Doping deteriorate the electrochemical properties of Cu₂Mo₆S₈Withthe increase in the amount of Fe element doping. But trace Fe added notonly to improve the capacity of rechargeable magnesium battery, whilethe more excellent cycling performance.