Porous Carbon-Based Nanocomposites Containing Fe2P Nanoparticles as Promising Materials for Supercapacitor Electrodes

Pseudocapacitive materials can enhance the energy storage performance of supercapacitors by making use of surface redox reactions. In recent years, different iron compounds have been investigated as pseudocapacitive materials, showing promising features for supercapacitor electrode applications. Carbon nanocomposites containing iron/phosphorus compounds have been prepared from porous carbon, followed by thermal treatment at different temperatures (700°C to 1000°C). The obtained supercapacitor electrodes were evaluated by electrochemical analyses using sulfuric acid electrolyte. The as-prepared nanocomposite contained nanostructured iron oxides or oxyhydroxides, whereas the nanocomposites prepared at 700°C to 900°C were composed of nanostructured iron phosphates. On the other hand, heat treatment at 1000°C caused the formation of nanocrystalline iron phosphides (mostly Fe 2 P nanoparticles). The Fe-containing samples showed enhanced specific capacitance (246 F g −1 to 447 F g −1 at 10 A g −1 ), which can be related to the pseudocapacitive contribution of the iron compounds. The sample heat treated at 1000°C exhibited favorable electrochemical performance, showing high electrical capacitance and good rate capability at 40 A g −1 . These results reveal that porous carbon/iron phosphide nanocomposites are promising materials for use in supercapacitor electrode applications.