Sodium Ion Storage of Carbon Supported Iron Sulfide Monochalcogenide in Carbonate and Ether Based Electrolytes

Abstract

Focusing on the electrolyte dependent electrochemical performance, sodium ion storage in carbonate and ether based electrolytes is evaluated for iron sulfide monochalcogenide (FeS) anode. Commercial FeS powder was ball milled and carbonized using sucrose solution to yield FeS nanoparticles embedded in a carbon matrix (FeS/C), which served as the electrode against sodium for the present study. The electrochemical performance of the electrode with carbonate and ether based electrolytes, 1 M sodium trifluoromethanesulfonate in a mixed solution of ethylene carbonate and diethyl carbonate and 1 M sodium trifluoromethanesulfonate in diethylene glycol dimethyl ether, was compared, respectively. The ether based electrolyte showed superior cycling stability maintaining 314 mAh g(-1) after 100 cycles at 1 A g(-1) current density whereas the carbonate based electrolyte was found to undergo severe capacity fading with cycling. At a high current density of 3 A g(-1) superior discharge capacity of 371.8 mAh g(-1) was obtained for the ether based electrolyte displaying promising rate capabilities. The comparative studies indicate that the ether based electrolyte is highly compatible with the FeS/C-Na system rather than the carbonate based electrolyte.