Charge Transport and Electrochemical Properties of Colloidal Greigite (Fe3S4) Nanoplatelets

Room-temperature superparamagnetic greigite nanoplatelets were synthesized using 3-methyl catechol as growth moderator and phase-control agent, in the presence of sulfur, thiosulfate, octadecylamine, and Fe2+. Dense films of nanoplatelets showed ohmic behavior in the 10-300 K range. In as-deposited films the resistivity increased with decreasing temperature (as for semiconductors), while in hydrazine-treated films it decreased with decreasing temperature, as for metals. The electrochemical properties of as-prepared greigite nanoplatelets upon lithiation/de-lithiation have been followed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrodes containing greigite nanoplatelets were found to be active in the lithiation/delithiation processes.