Lithium Iron Manganese Oxyfluoride High Energy Density Cathode

Abstract

Ball-milling has also been used to add fluorine atoms into rock-salt structures to take advantage of fluorine’s high electronegativity to raise the working voltage of oxide materials to create high power and energy density cathodes. New composite structures of metal oxides and LiF synthesized using this method have been studied as conversion reactions. In this study, LiF-FeMnO3 composites are synthesized by the solid-state method after mechanochemical-ball milling 3 mol LiF, 1 mol FeO, and 1 mol MnO for 12 h. The synthesized composites are characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques as well as the electrochemical properties. The lithium ion storage property is evaluated by galvanostatic discharge/charge experiments. Initial discharge capacity of 418 mAh/g at 10 mA/g was obtained. The coulombic efficiency almost remains 100%, demonstrating good high-rate performance and good cyclability. The high electrochemical performance is attributed to unique lithium storage mechanism, including conversion and intercalation/de-intercalation mechanism. Small particle size also provides some benefits to lithium ion storage property. This mixture of 3LiF-FeMnO3 composites is a promising cathode material for lithium-ion batteries with high power and energy densities. Figure 1