LiFe0.5Mn0.5PO4/C prepared using a novel colloidal route as a cathode material for lithium batteries (original) (raw)

A new colloidal route for the preparation of LiFe 0.5 Mn 0.5 PO 4 /C nanocomposite cathode material for lithium batteries is revealed. The method uses lithium dihydrogen phosphate (LiH 2 PO 4), ferrous chloride (FeCl 2) and manganese chloride(MnCl 2) in stoichiometric amounts with Nmethylimidazole (NMI) as the solvent and carbon source.The coating process is performed at 650 o C for 3 h under vacuum. Elemental analysis shows a carbon content of 3.71 wt.%, rendering the material to exhibit excellent electronic conductivity (9.29 x 10-2 S cm-1 at room temperature) and a significant increase in rate capability. Scanning electron and high-resolution transmission electron microscopy (SEM/HRTEM) images exhibited particles of uniform size (around 40-60 nm) that are covered by a 3-6 nm thick carbon layer. At a C/20 discharge rate and between 2.2 and 4.2 V vs. Li + /Li, the cell delivers a high capacity (140 mAh g −1) at the first cycle. The electrode stability was studied at C/10 rate, with only a small decrease (3.9 %) of discharge capacity over 100 cycles, which suggests that the new synthesis method for carbon-coated LiFe 0.5 Mn 0.5 PO 4 /C material is very promising.