Spray pyrolysis of conductor- and binder-free porous FeS2 films for high-performance lithium ion batteries

To improve battery performance a high cathode surface area is needed to maximize the electrode-electrolyte contact area. For this purpose, and for the first time, conductor- and binder-free porous FeS2 films through the entire thickness were deposited by spray pyrolysis. 1M of Fe(NO3)(3).9H(2)O, FeCl3, and NH2CSNH2 were utilized as the precursors. Film deposition was performed at 400 degrees C in open atmosphere. The deposited films were then sulfurized at 500 degrees C for 4h with H2S gas or in sealed quartz ampoules with sulfur flakes. The best crystallized films were obtained using FeCl3 and NH2CSNH2 precursors followed by sulfurization in the sealed ampoules. The films were characterized with X-ray diffraction, scanning electron microscopy, and electrochemical impedance spectroscopy. The films were cycled at C/10 and C/20 and despite having no binder or conductive additives gave comparable capacities compared to the literature finding for FeS2 powders mixed with conductor and binder additions.