Room-temperature liquid-phase synthesis of Na3FeF6 and its lithium/sodium storage properties

A Na3FeF6 electrode material for lithium-ion batteries and sodium-ion batteries is firstly synthesized by a room-temperature liquid-phase co-precipitation method. A scanning electron microscopy observation shows that the material owns pseudocubic morphology in primary particles. The charge-discharge tests indicate that Na3FeF6 for lithium-ion batteries and sodium-ion batteries delivers initial discharge capacities of 472.8 mAhg−1 and 121.1 mAhg−1, respectively, with decent capacity retentions, which is hardly influenced by charging cut-off voltages. The cyclic voltammetry results of Na3FeF6 as the electrode material confirm a two-step reaction mechanism for lithium-ion batteries while a one-step reaction mechanism for sodium-ion batteries.