homogenization, the mixture was transferred to the furnace and annealed at 800 ……for16hunder nitrogen flow. After this time, the powder was allowed to cool at room temperature. The crystallographic structure has been confirmed by X-ray. Elemental composition of the samples (Li, Fe, P) was determined by flame and graphite atomic absorption spectrometry (Varian 220 FS). To determine the carbon content, a known amount of sample was dissolved in hydrochloride acid (Carlo Erba, Analytic grade), the solution was filtered and the residue was washed with distilled water, dried and weighed.
The morphology of the samples was observed by scanning electron microscopy (SEM).
To prepare the electrodes for the electrochemical characterization, the composite cathode powder was mixed with poly-tetra fluoro ethylene (Aldrich) in the
weight ratio 97:3. The mixture was rolled into a thin sheet of about 100 ….from which 1.0-cm-diameter pellets were cut. AC impedance was employed to characterize the composite cathode, using a frequency response analyzer (FRA Solartron mod. 1260). Battery cells were assembled in a T-shaped hydraulic connector; lithium metal was used as counter electrode. A third LiFePO4
composite electrode was used as reference. Glass fibre disks were used as separators, and stainless-steel cylinders as current-collectors. The cells were filled with a 1 M solution of LiPF6
(Merck, battery grade) in ethylene carbonate/dimethyl carbonate (EC/DMC) 1:1. The cells were assembled in the dry-room (R.H. < 0.1% at 20 องศา).
Charge/discharge tests were performed using a Maccor Battery Cycler (Maccor 4000). The electrochemical tests were conducted at 20 องศา