Sputtered Porous Li-Fe-P-O Film Cathodes Prepared by Radio Frequency Sputtering for Li-ion Microbatteries
Résumé
the increasing demands from micro-power applications call for the development of the electrode
materials for Li-ion microbatteries using thin-film technology. Porous Olivine-type LiFePO4 (Lfp) and
nASicon-type Li3fe2(po4)3 have been successfully fabricated by radio frequency (Rf) sputtering and
post-annealing treatments of LFP thin films. The microstructures of the LFP films were characterized
by X-ray diffraction and scanning electron microscopy. The electrochemical performances of the LFP
films were evaluated by cyclic voltammetry and galvanostatic charge-discharge measurements.
The deposited and annealed thin film electrodes were tested as cathodes for Li-ion microbatteries.
It was found that the electrochemical performance of the deposited films depends strongly on the
annealing temperature. The films annealed at 500 °C showed an operating voltage of the porous LFP
film about 3.45 V vs. Li/Li+ with an areal capacity of 17.9 μAh cm−2 μm−1 at C/5 rate after 100 cycles.
porous nASicon-type Li3fe2(po4)3 obtained after annealing at 700 °C delivers the most stable capacity
of 22.1 μAh cm−2 μm−1 over 100 cycles at C/5 rate, with an operating voltage of 2.8 V vs. Li/Li+. the
post-annealing treatment of sputtered LFP at 700 °C showed a drastic increase in the electrochemical
reactivity of the thin film cathodes vs. Li+, leading to areal capacity ~9 times higher than as-deposited
film (~27 vs. ~3 μAh cm−2 μm−1 ) at C/10 rate.
Domaines
MatériauxOrigine | Fichiers produits par l'(les) auteur(s) |
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