Synthesis and electrochemical performance of Li2Co1- x M x PO4F (M = Fe, Mn) cathode materials.

In the search for high-energy materials, novel 3D-fluorophosphates, Li2Co1- x Fe x PO4F and Li2Co1- x Mn x PO4F, have been synthesized. X-ray diffraction and scanning electron microscopy have been applied to analyze the structural and morphological features of the prepared materials. Both systems, Li2Co1- x Fe x PO4F and Li2Co1- x Mn x PO4F, exhibited narrow ranges of solid solutions: x ≤ 0.3 and x ≤ 0.1, respectively. The Li2Co0.9Mn0.1PO4F material demonstrated a reversible electrochemical performance with an initial discharge capacity of 75 mA·h·g(-1) (current rate of C/5) upon cycling between 2.5 and 5.5 V in 1 M LiBF4/TMS electrolyte. Galvanostatic measurements along with cyclic voltammetry supported a single-phase de/intercalation mechanism in the Li2Co0.9Mn0.1PO4F material.