Synthesis, Characterization and Electrochemical Analysis of FeNbO4 Phase with -PbO2 Structure

The Nanometer and micrometer sized samples of FeNbO4 were prepared by sol-gel polymeric precursor and solid state reaction methods. Electrochemical lithium insertion was performed into both samples. Structural changes during the lithium insertion were followed by ex-situ XRD. The electrochemical charge discharge curves shows insertion of 0.3 Li is obtained in micrometer sized samples when discharged to 1.0 V and extraction of 0.1 Li is observed during charge. On the other hand, in the nano structured sample, insertion of 3Li/FeNbO4 were observed and during the first discharge, 2.2Li is extracted when charged to 3 V. A reversible capacity of 120 mA h/g is observed after 20 cycles.