Synthesis of MnO-LiF composite cathode material using NH₄F as a fluorine source

Non-intercalation cathode materials based on nanocomposites of lithium fluoride and Li-free transition metal compounds have drawn attention as materials for fabricating the cathode of lithium ion batteries owing to their high theoretical specific capacities and high redox voltages. In the present study, a nanocomposite of MnO-LiF was in situ synthesized by a quick annealing at 500 °C for just 5 min using a mixture of ammonium fluoride, manganese acetate, and lithium acetate as precursor. The synthesized composite is investigated by X-ray diffraction, scanning electron microscopy, nitrogen sorption, and charge-discharge measurements. As a lithium-ion battery cathode, it delivers respectively an initial discharge-specific capacity of 170 mAh g⁻¹ and a discharge-specific capacity of 137 mAh g⁻¹ in the 50th cycle at a current rate of C/20, which is equivalent to a moderate capacity retention rate of 80.6%. The novel synthesis approach proposed offers access to electrochemically active composites of lithium fluoride and Li-free transition metal oxides.