Ag4V2O6F2 (SVOF): A high silver density phase and potential new cathode material for implantable cardioverter defibrillators

作者:Sauvage Frederic; Bodenez Vincent; Vezin Herve; Albrecht Thomas A; Tarascon Jean Marie; Poeppelmeier Kenneth R*
来源:Inorganic Chemistry, 2008, 47(19): 8464-8472.
DOI:10.1021/ic800793e

摘要

The electrochemical reactivity of the cathode material Ag4V2O6F2 (SVOF) versus lithium, with a particular emphasis on the lithium insertion mechanism, was studied by means of the complementary techniques in situ X-ray diffraction, electron paramagnetic resonance, and high-resolution transmisssion electron microscopy. This study confirms the initial reports of a high capacity for SVOF of 148 mAh/g above 3 V and that the reduction of silver above 3 V (vs Li+/Li-0) leads to a loss of SVOF crystallinity until it becomes completely amorphous between the third and fourth lithiums inserted. Next, vanadium is reduced between 2.5 and 1.5 V (vs Li+/Li-0) for the fifth and sixth lithiums inserted. In addition, the polarization within the cathode is significantly lower for the vanadium reduction than for the silver reduction. The silver metal morphologies consisted of nanoparticles (similar to 5 nm diameter) and dendrites and were both seen in samples of lithiated SVOF.