A one-pot approach towards FeF2-carbon core-shell composite and its application in lithium ion batteries

Core-shell nanorod with FeF2 as core and graphitized carbon as shell was prepared by a one-pot thermal reaction using a mixture of ferrocene and polyvinylidene fluoride as precursor. The core-shell composite had an average length of about 1 μm and diameter ranging from 100 nm to 1 μm. The shell thickness was about 10-20 nm. Its electrochemical properties were studied in the potential range between 1.3 and 4.2 V at a current density of 30 mA g−1 at room temperature. The core-shell composite exhibited an initial discharge capacity of 345 mA h g−1. A reversible capacity of 217 mA h g−1 was maintained over 50 cycles with coulombic efficiency of 96% per cycle.